Performance Engines That Suck- The Porsche M96

Performance Car Engines That Suck- The Porsche M96

by Mike Kojima

A few months ago we did an article on 5 performance car engines that suck. This story was highly popular, and we have had many requests for more engines that suck. So here we go, in more detail, the next performance car engine that sucks, the infamous Porsche M96 engine.

In 1998, Porsche did a major change to their flat engine line up. Mostly due to tightening emissions standards, they boldly diverted their path from the traditional air cooling to water cooling. Thus was born the M96, Porsche’s first flat-6 water-cooled engine.

We didn’t really know too much about the M96 until a friend bought a 996 911 for what he thought would be a relatively cheap and reliable track car. Boy was he wrong! During the car’s first brisk canyon run days after its purchase, it promptly blew up! Thinking we could help him out, we tore into the engine to find that the M96 is a pretty diabolical nightmare of an engine with many faults, especially the early examples.

Let us show you just how diabolical these engines can be!

Check out our last article on the subject!


The evilest part of the M96 engine is the IMS shaft or more, so the IMS shaft bearing system. The IMS shaft is an intermediate shaft that is driven by a sprocket and chain off of the crank at the rear of the engine that passes through the entire engine and drives one the cams at the front of the engine.

The fact that the engine was designed with such a dumb method of driving the cams is dumbfounding to begin with. Why not drive them just by taking the drive from the front of the crank like any other company would?  We think this was done so the same head casting could be used for both cylinder banks. This would save some money but would also add parts and unneeded complexity to the motor, a bad idea.


So we got a sprocket and drive chain for the shaft at the rear of the engine that goes through the entire engine right at the sump level to drive two chains that drive the cams at the front of the engine. WTF!  Why is all of that necessary….

Our personal theory is that Porsche previously used intermediate shafts to drive large cooling fans on the top of their engines and with the switch to water cooling, they had to do something with a shaft. That is a joke, well maybe not…


What makes the IMS shaft really dumb is that Porsche didn’t use a durable bearing with forced lubrication from the engines oiling system for the shaft. They used a sealed bearing, sort of like a regular industrial bearing, or a skateboard.

The bearing proved to be very underrated for the job. In some cases, the bearing would fail outright. In others, engine oil would penetrate the seals and wash away the grease. With no grease, the bearing would fail. Strangely, failures seem to be more common with cars that are garage queens and sit a lot and cars that are driven gingerly. Cars that are track driven and are driven hard seem to have this problem less frequently.

It seems like about 8-10% of the M96 engines fail like this.  In early M96 engines, the failure rate is much higher. These failures have driven down the resale price of old Boxsters and 996 911’s and they can be had for bargain prices.

The early engines had bearings that would fail right away. When the IMS shaft bearings failed, the IMS shaft would whip around, damaging expensive stuff. Bearing debris would get circulated around the engine, wrecking havoc and finally the cam drives would fail to let the valves hit pistons. An IMS shaft failure would normally claim everything south of the intake manifold.



  1. If you’re going to purport to offer some technical analysis on why the engine “sucks” you should have researched some fundamental design aspects. In the first page alone there are several glaring inaccuracies about the arrangement of the M96’s main components–it should go without saying that any analysis predicated on these errors is fallacious.

    1. The intermediate shaft (what you call the “IMS shaft,” which is redundant) driving the valvetrain was in no way particular to the M96 and was in fact part of every modern Porsche flat six since at least the 964 model of the late ’80s. This includes vaunted, competition proven motors like the legendary Mezger engine which formed the basis of the GT1 Cup cars. The design is proven to be quite robust.

    2. The intermediate shaft is driven directly by a sprocket on the crankshaft, not by a chain as erroneously stated in the article.

    3. The chains driving each camshaft are on opposite ends of the motor; one chain is toward the front of motor, nearer to the passenger compartment, the other is toward the rear, nearer to the rear bumper. Even a cursory glance of your own photos shows the intermediate shaft with a chain sprocket on either end of the shaft.

    4. Where are you getting your statistics for the IMS bearing failures affecting 8-10% of cars? I’m not aware of any comprehensive database tracking IMS bearing failures–except maybe at Porsche itself.

    Come to think of it, there is no statistical data supporting any of your claims about the M96. Yes, some have had IMS bearings give out; some have had cylinder liners fail; some have had cracked blocks. That’s part of mass production; there will be the occasional worm in the coke bottle. The proliferation of horror stories on internet fora is not a sound foundation for such sweeping conclusions. The nature of these aberrations tends to skew toward disproportionate reporting. That is to say that an owner who suffers an engine self-destructing due to IMS bearing failure is far more likely to share his experience with a community than one whose car is running hunky-dory.

    Dried out leaky oil seals? Disintegrating plastic water impellers? These are common , age-related afflictions on any modern motor. Not design flaws.

    The M96 is not perfect. But it’s hard to think of many other contemporary production engines that offer the same combination of performance/character/fuel economy/ease of maintenance as the M96.

    1. The unique way that the IMS shaft rides on non-pressure fed bearings is unique to the M96 and one of the reasons why it is failure prone. It is driven by a chain from the crank, you are wrong it is not a gear drive. The IMS shaft does drive the cams on opposite sides of the engine, what is your point, I never said it didn’t. Having dealt with the M96 first hand I know it is a pile, ask any professional Porsche engine builder and they will tell you the same thing. Ask anyone who tried to track an M96 powered car, especially an early one. Look at all of the many aftermarket companies who make IMS bearing replacement kits, how do they survive if this engine was not problematic. The other failures are due to a poor design they fail prematurely. I am pretty sure by your statements you have never worked on one of these engines and have never seen one taken apart. Most off, look at the poor resale values of any Porsche with this engine.

      1. You are wrong. The earliest engines have better IMS because they have a double row bearing and the later ones are single which gave more issues to their owners. Google it, all the articles and 986/96 forum’s will tell you this. Before writting an arricle you have to do a research and not generalize it based on your unfortunate experience.

        1. All of the ball bearings are prone to failure no matter which of the 3 revisions that were done. The last iteration seems to be more reliable. From an engineering standpoint, it is dumb to have a dynamic bearing on one side of a shaft and a ball bearing on the other and the whole engine is a bad design for the reasons stated in this article. Like I said ask any Porsche Motorsports mechanic and maybe actually work on one of these engines. I am pretty sure you have never assembled and disassembled one of these engines and don’t have any experience with other engines to know differences in engine design. You probably own one of these cars and didn’t like what you read. Sorry.

          1. You are wrong! Before you write an article get your facts straight. The only source that may have statistics on how many engines have failed is Porsche and they have not released that information. You’re doing a disservice to people with your misinformation. On that note the dual row bearing are more robust than the single row. I personally replaced a dual row bearing out of a car during a flywheel replacement and guess what the bearing was spinning freely and it was fully intact. I might also add that the vehicle had 112,000 miles. Valve guides are prone to wear just like every other engine component. It is normal. According to cases the engines that are most susceptible to cylinder bore scoring are garage queens and not tracked or daily driven vehicles. By the way, cylinder bore scoring more prevalent on the 3.6l than the 3.4l engines. Further more bore scoring has occurred on the 997 as well.

          2. I am not wrong and have done my research. My Porsche motorsports associations, who I work with are people who deal with this on a daily basis and produce fixes for these issues, some of the most well known people in the Porsche tuning and motorsports industry. Just because you don’t like the answer doesnt mean its not true.

          3. I have to agree. That bearing should have been oil-fed.

            I don’t really agree that the M96 is oh-so-much-way-more horrible.

            The 10% IMS number is from a litigation in California. That was a fixed point in time. At that time that was the number.

            Over time, all the IMS should fail, just like all wheel bearings fail. It’s not oil fed!

            But it’s not that big a deal to yank the trans and put in an IMS Solution. I did it myself and I’m no genius mechanic.

          4. Now that the cars are older the occurrence rate is even higher. Of the people I know that have these cars, about 2/3 have had the bearing fail. Many of the older cars are also suffering from bore scoring. For the M97 you need to split the cases so that’s an even bigger pain.

      2. You are wrong. Period. I have tracked M96 equipped cars since 2000 and have NEVER had an IMS issue. Trailer queens have more of an issue than cars that are driven the way Porsche intended. The failure rate is LESS THAN 2%. What makes it an issue is the cost. As far as resale values, how many 15 year old cars with over 80,000 miles still routinely sell for over 30k?

        1. So your car is an outlier, there is such a thing. These engines do commonly fail catastrophically, any Porsche repair shop is full of said examples. Because yours hasn’t failed doesn’t mean that your engine has a good design. The Porsche’s with this engine have a much lower resale value than other models. A lot of you Porsche owners can’t get over the fact that your favorite company engineered a turd in their first attempt at making lower cost production water cooled motor.

          1. They definitely do not fail catastrophically on a common level. And that is not the reason resale is low. You are making opinionated statements that try to mirror facts. In fact, the IMS is not even the main issue with the engine. The best selling 911 in history will clearly have higher failures because it sold more cars. The failures rates don’t really exist in terms of percentage of cars produced, just number of failures.

          2. If you choose to ignore data and have no knowledge of statistics. So you own one of these cars and are bummed to find out you got a lemon.

          3. Calling Dan’s car an outlier is factually incorrect. Failure rates I’ve seen have ranged anywhere from 2-10%, and you agree with this. But when you call his car an outlier, now you’re claiming that he is in the minority as if the majority of engines fail. In fact, he is in the vast majority of Porsche M96-equipped cars. In fact, your car that failed is the outlier, and you’re trying to project this onto the majority of 986/996 owners who haven’t had this issue despite having the original IMS.

          4. Yeah, that’s really shitty and the nature of the failures is changing as the engines get older and now a great deal of them have the IMS fix. Bore scoring is now the major failure mode. This is a really old article.

    2. Imagine writing a story with numbered points trying to bring down the page.. but being wrong on everything. Best you sit pretty and stop trying to outdo a technical article. You clearly know very little about engines.

  2. The 986 Boxster as well as 987 Boxster and Cayman have been plagued by catastrophic engine failures.[61] Porsche settled a class-action lawsuit regarding the failures in 2013.[62]

    Some Boxster models manufactured between 4 May 2001 and 21 February 2005 have suffered catastrophic engine failure due to a fault with the intermediate shaft (IMS) bearing, which has resulted in a class action lawsuit against Porsche Cars North America (referred to as Eisen v. Porsche Cars North America). A settlement was agreed in March 2013, subject to court approval. Other types of engine failure experienced in the Boxster are not addressed by this suit. Additionally, the issues are not limited to the model years covered in the suit, or to the Boxster; the Cayman and 911 share the same type of engine and are also affected. In fact, all model years of Boxster, Cayman and 911 manufactured between 1997 and 2008 (with the exception of the 996 and 997 turbo models) are subject to the now-notorious IMS bearing failure.

    1. First of all they have not been “plagued by catastrophic engine failures” Less than 2% have been affected. And most of the 2% are trailer queens. . If you were a real engine builder you would know this. I have tracked M96 and M97 equipped cars since 2000 and have never had an IMS issue. My daily driver has never had an IMS issue either. Sound like you are not Porsche fan and probably drive a Scion.

    1. Well, as a pro engine builder that has had to deal with these issues like IMS shaft failure and D chunk failure as well as lubrication failure, I can certainly tell you that these problems are for real even if you cannot acknowledge them.

      1. I stick close to the Porsche community, especially the 996 guys/gals, and people aren’t having issues with the engines. For 15-20 year old cars, they are providing a lot of joy and reliability for people all over the world.

        1. Statistically, about 7-10% of these cars experience this sort of failure. It would be higher but most people and Porshe mechanics know to maintain that IMS shaft. When these cars are track driven the percentage goes up a lot unless the car is prepped. As any Porshe race shop about these engines.

          1. The cumulative failure rate is much higher, enough to support several aftermarket companies.

  3. please…stop it… InterMediateShaft shaft bearing… why the redundance?
    It’s not just the 3.2 boxster s that suffers less from the D chunk failure, the cylinderwalls on the 2.7liter standard boxsters are even thicker. never heard one of those fail.

    1. Instead of arguing about numbers and pointing fingers, it would have been better to survey some PCA or Rennlist members on their satisfaction rates., and reading comments in, not just getting paid to write a a one-sided article based on mechanics who only see the repairs. Kind of like asking an oncologist is cancer is common.. The 996 had faults, so did the 964 and the 2.7 engines of the 1970’s, and as mentioned there are many aftermarket fixes. At 106K miles, the IMS bearing on my ‘00 was replaced with a clutch replacement, it spun without wear. As stated previously, the best cars are those that are driven hot and hard, not sitting in a garage., which ironically are the ones now getting the most money. I drive my car like a Porsche,, 4-6K revs and occasionally hit redline. The bang-to-buck ratio is higher than any other sports cars today. Potential buyers need to remember, it’s a $80K performance car, even if they sell for $20K used. But it’s not a race car, and tracking one requires addressing oil starvation issues.

      1. Instead of being in denial, maybe you should use logic and look at data, engineering principles, and listen to the experiences of people who deal with these engines for a living. Assuming that this is a paid article and thus wrong is a fallacy of logic. This isn’t a paid advertorial at all, it’s a review of facts about this motor. Casualty revving a car to 4-6k and an occasional burst to redline is not sports car use unless your sort of use is driving to cars and coffee and parking. A Prius gets driven like this. A Porsche is meant for hard sporting driving and track use. Track day use is not necessarily racing as it is not safe or legal to drive super fast on the street in this country. So you bought a turd and don’t like facing the truth, don’t blame the messenger.

        1. Watching the denial, anger, and inane defense of this engine is pretty damned funny. I bought a 2000 996 C2 in October of 99. I made 30k on it and the IMS bearing just exploded. When you pay $90k for a stripped sports car and its engine fails catastrophically on the highway at speed, I’m pretty sure that’s bad. I’ve owned dozens of other cars of exotic origins. Never had anything like that. When I called the 800 porsche support line, they sure didn’t act like this was news. Thank you Mike for your piece. It is time we show the emperors balls are dragging on the pavement.

  4. What an awful review. This guy has no idea about technical details of engines. Maybe an LS engine is the most advanced engine in the world for him.

    1. Actually, perhaps you are butthurt because you own one of these engines in your golden chariot Boxter or 996! How dare anyone criticize your perfect machine. It’s pretty obvious that you don’t work on engines internals, particularly this one and have no clue on engine design or engineering or any direct experience with any engine.

  5. Garbage article. A lot of assumptions and one sided representations of a problem that has proven to be no more or less obvious than any other manufacturers’ engine issues does not make for intelligent writing.

    You haven’t broken any ground here or stated anything interesting and worthy of discussion. So, basicallly, this article is a completely useless read (a la National Enquirer).

    I own a 99 C2 with an original unmolested M54. 70k miles and no hint of impending doom. These engines REQUIRE far more frequent oil changes than others and to be run at higher revs during operation. Of course they do, they’re race engines fitted to street cars.

    Lose the doom and gloom crap and realize the application of such a motor and stop rehashing useless knowledge and find some thing insightful to write about. Writing isn’t simply stringing phrases together; it’s about conveyance and the performance of ideas.

    1. Another butt hurt owner of one of these shit engines that has never worked on one, never seen the insides of one and has no engineering knowledge of engines. There are facts, a high warranty rate and tons of aftermarket solutions developed for out of warranty repair. An entire large aftermarket with multiple suppliers has sprung up around fixing these engines issues. If it was not an issue, the economics would not support these businesses!

      As an engine builder, I have been involved with fixing some of these crap piles. From working on, developing for racing and competing with plenty of other engines from Porsche and yes other manufactures you would know that this engine has many bad design features that we covered here. Ask any reputable builder of racing Porsche engines and they will roll their eyes when you talk about potentially racing one of these. I would say you understand very little about engines, don’t work on your car internally and don’t do much with your car beside tool around in it. Or maybe not when you consider that the M54 is a BMW engine.

      1. The M96/01 and M96/03 (Carrera-engines) are no racing engines. They are sports car engines which can take occasional tracking. If you want to race there is the M96/70 engine aka Mezger. Have you ever tracked 928? Do you have any idea of the oil problems of the old air cooled ones?

        I am quite sure that statistically the M64/01 (964) has caused more trouble to owners than M96/01. Almost all M64s needed new sleeves – and exactly all of them drip oil.

        If you still want to race a Carrera-engine you should go for the X51 options with deeper pans and better baffles. And you should always run an M96/01 and 03 close to top oil level. Long corners are the bad ones. On roads you do not find curves that turn well over 90 degs. On race tracks yo you can have over 200 degrees easily. They starve most engines out of oil. Have you ever heard that it is different horses for different courses? There is a 911 called GT3.

        And “ask any reputable Porsche …”. That is like running out of good arguments. I for one really dont have to ask anyone. I did my homework.

        1. The Mezger is an entirely different engine with a way more robust design. The M64 is a different engine. A 928 is an entirely different engine and car. This is an article about the M96 engine. About your comments about oil starvation and the fixes, well no shit I wrote about the exact same thing and how to fix it in the article, maybe you should read it again. The 996 GT3 has a Mezgar engine which is not an M96. You didn’t do your homework, you are vomiting stuff that has nothing to do with the premise of the original story.

          1. The Mezger engine has an M96 part number it’s M96.76 or M96.79 the 996 Turbo is M96.70 but it’s not really related to the M96 in the Carrera as stated above.

            The Mezger are dry sumped, Nikasil sleeved engines with a direct oil fed plain bearing on the IMS shaft, no Variocam etc.. etc.. They’re a far more robust design.

            It’s a race engine after all.

            The M96 is a reasonably good mass produced road car engine, which is designed for spirited driving, I’m pretty sure Porsche released a memo at one point suggesting the M96 isn’t suitable for track use.

            I own an M96 road car, and as a road car it’s alright, if you look after it, change the oil frequently and keep an eye on what’s going on, it can be a fun car, but it’s far from perfect, is this article a little harsh?

            Yes I think so but it’s also a valid opinion, as denying the M96 has failed previously is erroneous, it has failed and pretty spectacularly on occasion.

            I personally prefer the dual row bearing and the engines with KS pistons as I haven’t seen a KS piston engine bore score yet, but I have seen them D-chunk, the porous block issue doesn’t really exist anymore, all those were resolved or failed at low enough mileage to ensure they’re probably not on the road anymore.

            The moral of the story I guess is the M96 can fail, but it doesn’t mean you can’t own one, just have deep pockets if it does..

            But any Porsche engine can fail and at some point has failed, that’s always the risk with an older Porsche.

          2. Just to add a further note, I needed those deep pockets as the IMS bearing failed. Wouldn’t touch an M96 engine again, it’s repaired now and sold on at a hefty cost.

  6. Mike, given your dislike for M96’s, why not do something else for a living and enjoy yourself. By the way, I own a 2004 996 Carrera, 45K miles, have only had to replace the water pump, 10K miles ago.

    Sorry you were mistreated as a youth.

    1. It’s not a matter of having a like or dislike to a mechanical thing. Some things are designed better than others. The M96 is not a very good design. It was Porsche’s first foray into water cooled engines and they didn’t have the experience. If you have one of these Porsches and do brisk but not racing sort of driving and drive it frequently you have a good chance of it lasting longer. If you do track days and really drive your car hard, the chances of issues go up. Think about it, there is a whole lively industry of companies that specialize in fixing these engines issues, not to mention class action lawsuits, etc. Think about it, if this was a solid engine would this be so? Economics would not allow this.

  7. Some of the replies by the author of this article just goes to show how un-professional and ill informed he really is. I was actually laughing out loud the majority of the the way through it bless him

    1. Laughing at what, the accuracy of the issues? Can I ask you what your experience with these engines is? I can probably guess you own a Porsche with one of these engines but you neither compete or work on it yourself.

  8. I have been working on high performance motorcycle and automobike engines for 40 years. BMW to Honda to MB , turbo and normally aspirated. As much as your Porsche owner wants to believe that these cars can be tracked and then used as a daily driver without enhancements to the drivetrain your a hopeless romantic. For the average driver that enjoys the comfort of ac, power seats, cruise and a peppy little engine these cars are great. You start beating on them as if they were purpose built track cars somethings gonna give. I have installed several dozen IMS bearings upgrades along with chain tensioners,wster pumps, deep sump kits and cooling system upgrades on m96 engines with under 35k miles. Of the people I keep in touch with have not had a failure. Some with 200k miles. They are cool cars and a good value. They will break eventully , but to avoid the kaboom fix the ims and reverse the stigma.

  9. I have a 02 c2 cab with 130k worry free miles. Regular oil changes with redline and nothing on the filter element. The m96 issues are very over stated. As reliable as any car I’ve owned and certainly more reliable than an air cooled 911, I’ve owned 4 and still own 1.

        1. Yes, that is an awful failure rate for OEM engines in normal use. It is make the company bankrupt bad. Normally what is considered to be acceptable and an OEM target is a three-sigma failure rate which is 99.7 percent.

      1. Will you at least stick to a percentage? You spit so much bullshit you can’t even keep your own lies straight! First it was 8-10%, then 7-10%, now it’s 15%?

        1. You need to study your own engine. Do some independent research and talk to some mechanics that specialize in Porsche they will tell you. There is a whole thriving aftermarket industry that specializing in fixing the bugs in these engines. Sorry if I told you the truth that your treasured Porsche has a motor that is a turd and you took it personally.

  10. Im guessing this article is based on one if not two things:
    1. Content is sponsored by LNE
    2. A M96 banged your gf (or bf) repeatedly and better than you.
    Either way this is a poor piece.

    1. Reality check, there are a quite a few other people that make parts to fix these engines issues besides LNE. Lots of aftermarket support to fix issues equals engine with problems. Lots of warranty and a class action lawsuit means issues. Sorry to insult your perfect car by presenting some facts about its engine. Even Porsche messes up sometimes.

      1. So by that standard every single car that is worth collecting is shit right? Not saying this is a collector car but your standard seems totally off.
        And yes there are several companies that make aftermarket products for isdues as any robust hobbiest car group has. Where uour tainted review is showing its colours is by stating all these disastrous ills are solvable by buying parts from lne.
        Youre not evenyellow journalism youre total shit and out for a buck. Plain and simple.
        That and the m96 is a better ride than you for your gf/bf

  11. “It seems like about 8-10% of the M96 engines fail like this. In early M96 engines, the failure rate is much higher. ”

    This quite the contrary. There is good reliable data from the Eisen Class Act documents based on over 50 000 US import M96-cars (Boxsters and 996 Carreras) and Porsche warranty statistics.

    [ , Chapter I, paragraph B ]

    The earlier double row IMSB had a failure rate of <<1 % where as the later single row IMSB had 4-8% depending on the Porsche Center. In California there was one anomaly with 10%.

    The load capacity of the later single row is half of the original double row. The later bearing is simply underdimensioned.

    This is not an opinion nor beliefs. This is credible data! A good journalist does his homework!

    1. This is data that is several years old and the cumulative failure rate increases greatly with time as the population is not growing.

      1. That is true but you still did not do the homework. The early double row is not a problem and it is fail-safe in its nature. The trend still goes. The ones that break are mostly the 3.6 liter engines, not the early double rows. The IMS problem of the early ones is the shaft. Not the bearing. But all and all, go ask Jake Raby or Charles Navarro and they will tell you that the early double row is not a problem.

        There are so many mistakes in your article … beliefs rather than actual verified data.

        1. That the OEM double row does not fail is not based on data, that is your belief. In the Porsche racing community, these are known to fail as well. A double row bearing can have more load capacity but it does not change the fact that the IMS shaft has a pressure fed plain bearing at one end and a ball bearing on the other. The floating plain bearing will cause axial stress on the ball bearing which only has one degree of freedom in its movement. It is not a good design. Speaking of errors, you throw out the names of the owners of Flat 6 and LNE as a back up to your supposition that the OEM bearings do not fail but they are talking about their own aftermarket heavy duty double row retrofit kits, not OEM parts. This does not support your arguments at all if anything it just supports what I said.

          1. If you go to the pages of LN and Flat6 you will find a statement that says the double row bearing is not a problem like the single row. And the numbers do back this up. Raby had to do this to remain credible after the Eisen Class Act documents surfaced up. This is not an opinion or a view like you are representing. You are spreading rumors and gossips and repeating forum beliefs.

            The following is Jake Raby’s statement.


            [ ]

            You are doing your homework badly!

            M96 leaking oil. Can happen but consider the aircooled the M96 keeps the garage floor clean.

            AOS ! What kind of a problem is that? It is a device that has a life span just like plugs or water pump. AOS can fail in any car where it is. It does not produce any fatal failure.

            I kinda bet that you have never worked on an M96 and the skin on your hands are soft and clean.

          2. Mike having hands that are soft and clean? You obviously don’t know who Mike is and his history in this industry.

          3. What Jake Raby is saying is referring to stock OEM parts. He still advocates and makes a good living by replacing all OEM IMS shaft bearings with heavy duty ceramic bearings on every engine he builds. Also are you saying the M96 is air cooled? I am pretty sure you dont understand the function of the AOS with this particular engine and what implications that its internal failure can have on this engine.

          4. Ian, you are right I dont know who Mike Kojima is but he certainly does not know his stuff. Did you read what he wrote about the wrist pins. Yeah, the wrist pins require an IQ higher than 84, that is true, but then how was it done in the air cooled ones.

            This Mike something simply does not have the facts right!

          5. Installing the wrist pins and retaining clips through a long hole through the cylinders in sequence with specialized tools and a borescope is not how the wrist pins are installed in the air-cooled motors. In those, the wrist pins are installed conventionally or with the rod on the crank with the cylinders lowered down on them. I don’t think you have worked on either of these motors.

  12. Mike,

    Thanks for publishing this article. Having owned two 1999 996 cars (both of which had replacement crate engines) it’s refreshing to hear somebody speak some truth about the M96 engine. Both of the engines replaced in my cars were from bore scoring on cylinder six. Fortunately, I never had to pony up the money for either of the $20,000 engines. I enjoyed my cars, maintained them and sold them when I wanted something new.

    I think a lot of the readers of this article are missing the point. The M96 engine isn’t perfect and it needs a lot of aftermarket work in order to make them truly bulletproof. I’ve met Jake Raby multiple times and I’ve never seen him drive a car with an M96 engine. Coincidence? Probably not. The fact that he’s made a fortune off of these motors either means that all of these engines need his parts or it is all fear mongering. I think it’s a combination of both.

    I’m sure you all are going to hate me for this but sometimes the truth hurts. Either way, I hope everyone enjoys their cars and maintains them well. The 996 is a great value—but it’s a great value for a reason.

    1. Thank you! At last, someone who gets it, and understands logic! The way people unlogically defend the attributes of their material property in a personal way never ceases to amaze me!

      1. Listen Mike, Ive produced you real facts with references. You have done nothing but promoted forum beliefs. Dont talk about logic, dont think that you represent a scientific view here. You are promoting beliefs and legends rather than reality. I got a 30 your bg in science and engineering both theory and practise.

        Do your homework better!

        1. You are not presenting facts, just expressing your opinion. I actually worked on one of these shitpiles along with many other engines. I am sure that you do not work on this engine other than possibly changing your oil and basic maintenance. I did my homework and carefully state in the article what it takes to build a bulletproof M96. You seem to suffer from selective understanding.

    2. Jake Raby produces excellent parts! No question! Absolutely! And LN Eng is at the top of the cream. Absolutely!

      But Raby is also the worst bad mouther of the 996. Follow the money! Why? Because he is promoting his business. He always says he doesn’t make any money of these producst and patents … but just open your eyes and see what he does for living!

      “If your engine ticks – it is scored! Bring it to us!” BS!

      Yeah, M96 (01 and 03) are not perfect engines. They need love and taking care of and they are is engines for someone with soft skin in his hands. They are also about 15-20 years old! Porsche made learning mistakes with them – but M96/01 is still a lot better engine than , say, 3.8 M97/01.

      And really, RMS, an issue!

      Do you guys realize that you can buy 10-15 996 Carreras with the price of a single new GT3 RS. Now is the 991 GT3 RS 10 times better. It is more powerful, it is faster but not 10 times and in a B-road 996 Carrera is much better option than the rather big and stiff 991 GT3 RS.

      1. Again what you are talking about has nothing to do with the premise of the original story, that the M96 is a poorly designed engine as is the M97.

        1. You obviously do not have any scientific or academic bg cause you can not differentiate facts from opinions, nor references. You have not done your homework.

          The best credible data we have is from the Eisen Class Act. And that is statistically good data. It proves beyond any doubt that the early M96/01 double row IMSB is not a real issue where as the M96/03 single row is. You also have Raby’s statement. Your understanding of the wrist pins, AOS and RMS is amazing and totally mixing kettles with pans.

          You also fail to understand that M96/01 and 03 engines were built around 165 000 or so. Even if you have 100 D-chunks that is like 0.6 per mille and that is like 0.06% which is pretty much normal in this power class engines. This is also something that Raby (deliberately ?) forgets all the time.

          Im telling you M64 has certainly been more problematic if you really look into the statistics. And mind you, evern Mezgers fail at times. I agree that M96 Carrera engines are not perfect and not the best what Porsche has created but also not the worst. They are much better engines than their forum rumor based, rabies amplified reputation is.

          1. You keep saying the same things over and over. So I will repeat myself as well for one last time. Your assumptions are flawed, you are looking at 5-year old data from a population that is shrinking so the current occurrence rate is much higher. You are also pulling some statistics like cylinder cracking out of your ass. In a population of automobiles, 5 years is a long time for a fixed size population. It is clear you have no understanding of the implications of other failures or how to assemble an engine, or how to control tolerances in an engine when machining, rebuilding and blueprinting. This engine is pretty hard, so expert, how do you align bore this particular engine? Also, where is your vetted statistical evidence to your claim that the air-cooled engines are super problematic since you like throwing this out as evidence of you doing your “homework”. The engine issues that Tony Calles one of our locals sees on the M64 are relatively minor, such as valve guide wear, oil leaks and distributor belt failure and none are catastrophic like you see on the M96.

  13. mike you don’t know any real porsche mechanics. maybe some, I’ll tune your car and bolt some shit on mechanics. What PMNA mechanic works with you. Show us your porsche race car and not your purple gt3 with shitty bolt ons you got for free. You should stick with your shitty nissans, Mike kojima is full of shit.

    Ian, whats up with mike soft hands how would you know how his hands are does he stroke you off. Bunch of idiots writing.

    1. I know most of the guys at PEC down the street from us, BBi, Vision Motorsports, Essa Autosport, Bismoto Engineering. I don’t currently own a Porsche race car but I have worked on GT3 RSR, admittedly not for engine stuff but then again that’s not this engine.

      1. uhhhh, PEC is not PMNA, BBi used to build average exhausts systems (don’t know how good or bad of a shop they are, vision motorsports dwaine was a low level wrench monkey at andial, mike essa don’t know if he’s a porsche dude, and really Bisimoto are f/ing kidding me bisi barely started playing with porsches. WOW there are so many hardcore porsche guys in SoCal/LA and those are who you listed off….. what a joke. Sir you really don’t know too much.

  14. I think somehow people need to write without thinking, possibly the article is slightly silly so here goes ,where I live I am surrounded by Porsches many use this engine ,some have problems as said in article however the resale does not reflect that they are perceived as grenade engines .I Germany there are some who are rebuilding the engine case ,and again how many ? So I think acticle is accurate but at the same time drama helps sell and the more drama the better …by the way shows that you sold 4 kits ,so yes there is a demand .

  15. This article is bang on. As the past owner of a 2000 Porsche 911 (now affectionately called ‘boat anchor’), it failed well before 70K and Porsche said “too bad, so sad”. Even though it was bought there brand new and serviced regularly. They then quoted us 30K to fix through them. Lowest quote we’ve gotten locally is 15K. That’s a whole chunk of change! Porsche settled a class action lawsuit against these engines – class action means many people involved. Just because it didn’t happen to you, doesn’t mean it won’t happen.

    1. I wonder if there is a business model to swap 9A1 engines into cheap 996 chassis with blown engines that are plentiful to make good drivers.

  16. I love this!
    When something is repeated enough it becomes gospel.
    This situation allowed me to buy a nice, perfectly running early 996 for short money. I then had ALL the big known issues addressed with a rebuild, IMS Solution, Nickies, etc.. I ended up with a fantastic 911 with a NEW engine for less than I could buy one of the more sought after 911’s for!
    I’ve been driving the wheels off it for years.

    The INTERNET is dangerous place. Anyone can claim to be an expert. Just because a person gets their hands dirty and works on engines doesn’t mean they have risen to any high level of expertise.

  17. Couldn’t agree more. The IMS design on the non-GT is utter garbage.

    The cylinder design the same. Who on earth would just leave as coated cast aluminium bores in a performance engine?

    Absolutely nuts and actually quite typical of German engineering – they do have the propensity to engineer convoluted designs with built-in weaknesses.

    FWIW, I actually enjoyed my time in a 1998 M96.01. Very smooth all the way to 7,300, and sounded great. Didn’t fail on me.

    I still have my M96.76 GT3 which is a completely different animal and does not have any of the same flaws.

    1. … Exactly!
      My 996 C4S is “exactly” what it is, not what anyone could say about it in the internet … much in the same manner as I am what I am, not what the others call me … specially me being from the “pre-internet” generation!…

  18. These engines are absolute pieces of s**t, there’s no two ways about it.
    Sorry but they’re a f**ing disaster and Porsche should hang it’s head in shame.

    Sit there and wax lyrical all you like but when your M96 engine shits a brick and you need to rebuild it, believe me you will be wishing you bought something else.

    There’s a reason these cars are cheap, so unscrupulous dealers can make a profit at your loss.

    Stay clear, don’t even consider buying a 996. They’re just absolute pieces of crap, but a 350Z, S2000, Z3, SLK55 anything.. Just don’t buy one of these absolute sh** boxes.

    Complete joke of a car.

    1. Jim……Your a f—— idiot and you don’t know what the f— your talking about ! PERIOD.
      I’ve had my 1999 996 with the M96 for 101k now and it still runs like new !
      I have three friends that own 996’s also and haven’t had any trouble with them as well, because the dual-row bearing ! We change the oil on time and theres nothing to worry about !
      Your a dum ass !

      1. The cars are great, the engines of this series aren’t. There is a reason they are cheap on the used market. 85% of them don’t have problems. A 15% failure rate is horrible, when the industry target is three sigma or 0.30 % The engine is horrible design if you read about the reasons why. There is a thriving aftermarket with at least 3 companies making countermeasure parts. Dual row bearing cars are just as problematic as the single row. Not performance parts, repair parts. Sorry to pop your bubble, you engine sucks. Don’t take it on the track, reasonably driven and well maintained on the road and it can last. Really, owners of these cars are the worst, they have either experienced problems and understand or are hugely insulted that you stated that their golden chariot isnt the end all of transportation to be envied by all.

  19. I was lusting for an affordable Cayman right up until I started reading. Here is my thing WTF? WHY is it so many other manufacturers manage to build high performing engines that DON’T end up with all the real or imagined fear mongering? And more than that WHY would such a capable company FAIL to completely erase all the fear damage by doing things to truly make it right ? One thing they COULD have done would have been to ASAP move to an entirely new design …. To me it almost seems like Porsche sort of enjoys having this stigma around their lower tier cars especially older ones now that might otherwise more heavily infringe on sales and price points of their pricey more current offerings. And hey WHY did they EVER put weaker IMS to begin with??? WTF?? Obviously they COULD choose to profit less on replacement engines and make owning the suspect model years worth owning if the motors go south…. The huge cloud cast over all these older 996 etc cars that look so much like the brand new ones renders them no threat to New values…….As much as I would loved to to have owned and driven a Porsche Cayman all this CRAP has just TOTALLY turned me OFF … the company itself SUCKS if you ask me…I HATE companies that treat customers like milk cows ….cold hearted greedy gougers ….Luckily Porsche is far from being the only fun car to own and drive so I need not lust anymore after one. What I love to see is Japanese companies creating wonderfully reliable sports cars at a fraction of the price of Euro cars …. I’m hoping Toyota/Subaru or Mazda creates a mid engine Japanese version of Boxter Cayman for $40k ….they could do it too by simply y sharing a common platform between three companies. Already there is to be more powerful 86/BRZ out in 2021 (250 HP 2700llb for maybe $35kish?) and the next gen Miata is rumored to be well over 200hp and only 2300 llbs. I give not one crap what name of manufacturer so long as the car delivers similar experience …ultra fun to drive BUT be Stone reliable with no dark cloud hanging over reputation

    In the meantime just to have something fun to drive while I shop for/wait for a more appealing sports car? I snapped up a nearly brand new MX-5 Club for barely over $20k ….damn is it fun to drive! A Cayman would be more of the practical DD but ….for as a pure toy? I have a hard time believing one could be more fun than this little Miata….Maybe I’ll even toss a CARB legal Edlebrock supercharger in and see what a 250hp MX-5 is like. Entry level Porsche is about to become even more irrelevant for all those that could care less for brand/image

    1. No the 981 has the 9A1 engine which is vastly superior. The 9A1 replaced the M series motors in the 987.2 and later models.

  20. The butthurt by the Porsche guys in here is real. All you have to do is look at the classifieds to see what the real story is. Every other car sports a “IMS upgrade” and the resale prices reflect the issues.

    1. Really, Porsche guys hate when they think you are insulting their golden chariot or extension of their manhood.

  21. I’m so glad these cars have these issues (last I looked, LNE said it was around 2% of these cars that experience this failure over the course of their entire life – not that high!) As a result, I picked up a 986S for $6800 that already had the LNE upgrade. It had 148K on it when I bought it, now it has 182K, and still runs like a top. I love it and there’s no other car on the used market that offers an experience like this for a price like this. Thanks to everyone who repeats the story of how much these engines suck – keep it up! 🙂 I wouldn’t have otherwise been able to own a Porsche. Yeah, I hate the M96 engine too! It’s terrible! Off to drive my terrible car that I definitely don’t love at all…
    I think it’s funny, when these cars are discussed, that nobody ever mentions how incredibly easy they are to work on – I’ve owned over 30 cars in my life – European, Japanese, and American, and this is my favorite car to work on I’ve ever owned. Everything feels like they were thinking about what the experience of fixing it was going to be like… there’s access panels or little cutouts or just good access to the fasteners for everything I’ve had to replace on the car so far (mostly suspension parts, ignition stuff, and evap valves). The suspension is particularly easy to work on – kudos to those Porsche engineers! I mean, it’s mid-engined, and yet it has better access to the front, bottom, and rear of the engine than any other car I’ve ever seen!
    But it’s definitely terrible. Terrible, terrible car. Don’t buy one.

  22. Mike, I admire you for putting up with all the insults from the Porsche fanboys for the last two years regarding this article. You are right, of course. The upside of this, for me, was that I was able to buy a pristine 986 S for a song, recently. Truly a blast to drive. This winter I will be doing the usual stuff to make it a reliable (if possible) long-term weekend car.

    1. Yup, replace the IMS shaft bearings and do routine maintenance before anything happens and it should serve you well. I would rock that on the street, just would not dare to track it.

  23. I’m no mechanical engineer or scientist, but I’ve owned several examples each from 964, 993, & 996 generations, and by far the least problematic mechanically have been 996. None of these examples were Turbo or GT variants.

  24. Mike, thank you for writing an honest piece and putting up with absolute shit from M96 engined car owners in denial. I might give them the benefit of the doubt if your article was the only one with an adverse opinion on this lump. But it isn’t. There are multiple sources, some with excellent credentials, that share your opinion that the M96 is an expensive and unreliable turd of an engine. And the secondhand car market place is an honest arbiter of the the truth. I’ve recently bought a 2009 Boxster. Yes, the one with a 9A1 engine. I paid a bit more for the peace of mind given by the knowledge that it is much less likely to explode than a M97 engined car. And I don’t think I’m the only one doing the same. Keep up the good work. Informed and honest opinion is a rare find on the internet.

  25. Thankyou for the article Mike. I was about to buy one of these in 48hrs for a project car as an intro to working on cars myself, also was looking forward to a bit of track with it too. I remembered you from SCC days, so I thought I’d see if you had any articles up. And, well, I’m not rich enough to buy one of these cheap cars. So, I’ll keep searching around for a 2007+ 350z. Keep well.

    1. Look for a 987.2, those have a way better engine and check out our 987.2 project car. This is a superior car to a Z33. What I hate about the Z33 as a track car is super weak hub bearings and severe brake knockback.

  26. A few comments:

    “The fact that the engine was designed with such a dumb method of driving the cams is dumbfounding to begin with. Why not drive them just by taking the drive from the front of the crank like any other company would? ”

    The idea is to gear down the speed, to increase chain life. As for driving cams on both sides of the engine, it’s for packaging reasons. A 911 engine bay is a TIGHT place.

    As for the next point, cracks/d-chunks and sleeve slipping in the same paragraph? Well, that’s interesting. The cracks/d-chunk failures are catastrophic because the engine doesn’t have sleeves at all, so how can an engine without sleeves slip them (more in the paragraph below). Also, only the larger capacity engines turn oval and crack. The Boxster 2,5 and 2,7 liter engines usually don’t fail. The Boxster 3,2 rarely. Then you have the 3,4 and 3,6 996 engines which fail a lot more.

    As for engines with sleeves? Yes, there were some. Kolbenschmidt (the company which produced the blocks and has the patents for the Lokasil production process) actually dropped the casting machine while moving it and while it was repaired they ran out of blocks. To avoid stopping the production at Porsche, Kolbenschmidt suggested to fix blocks that were earlier rejected in quality control. They usually had a casting defect or porosity problem so by inserting sleeves in failed blocks they would be made functional again. Although some of them slipped. That happened pretty soon after purchase so Porsche has replaced the engines in those cars on warranty. Note that this was in 2,5 liter engines in late 98 and early 99. So NOT 996 engines (which are 3,4/3,6 liters), only 986 Boxsters. This also links to the porous casings problem. So again, few blocks, early on. And unfortunately it’s common with problems early in production runs.

    Same with RMS issues. Problem early on, rarely a problem on used cars. The reason its got so much attention is that you wouldn’t expect your brand new Porsche to leave a puddle of oil in your garage after three weeks. But Porsche fixed it on warranty.

    As for the wrist pins? It’s cumbersome when rebuilding it, but if you were to list every engine with a cumbersome solution you’d be writing a very very long list. Not really a design fault per say.

    Water pump, AOS, well nothing lasts forever, and hydrolock from AOS failure is rare. The biggest issue is the placement which makes it a PITA to replace.

    Finally. M96 isn’t M96, there were many models and while M96.01 / .02 / .03 and .04 were prone to failures, others like the Mezger-designed M96.70 (996 Turbo), M96.76 (996 GT3) and M96.79 (996.2 GT3 / GT3RS) are absolutely glorious engines. As for experience, among many Porsches I’ve owned, there is a 996 Carrera that cracked open a sylinder and a 996 Turbo that was tuned to an absolute beast. Loved them both.

    So while the M96.xx (where xx is any number below 70) absolutely do suck they suck mainly because of IMS failures and cracked sylinders, the rest on the list is mostly non-issues. On the other hand the Mezger M96 engines absolutely rule!

  27. haha maybe i just avoid this piece of shit and drive my bmw z4 e85 without any troubles. Ridiculous “preventative” maintenance procedures for engine/car that dont even accelerate under 5 secs 0-100kph. Anyway all that alusil, lokasil, silitec, lds, twin arc spray coating and what else “save money and run away” -coating is just digging blood out of the nose. It’s gotta be either nikasil or cast iron liners for good start.

    GT and turbo models during VAG era are fine, i wouldnt be that sure about 991 engines though.

      1. the alusil coating in turbos and gt models is treated with more heat to make it last more heat fluctuations and power

  28. LOL, the fanbois sure came out of the woodwork for this feller… Yeeesh.

    Probably the same guys who will flame you for replacing stock wheels with non-Porsche wheels… Hell, anything aftermarket other than maybe some megabuck Ti exhaust ist verboten in that crowd…

  29. Nice article, and entertaining. I’m a Porsche owner and not offended. There were a lot of poor design choices in the 996 era and a lot had to with cost and environmental concerns. Also living up to the Mezger design which lasted from 1964 for over 50 yrs is tough. Even 991.1 Cup cars had mezgers. When Porsche went racing they didn’t use the M96 non-Mezger variants for a reason. Does that mean a M96/7 powered 911 is a turd? Not really, they are good cars and can be enjoyed on the street or track. Wish people wouldn’t take another persons opinion so personally!

  30. Written as a sensationalistic attack on the M96 engine, much of which is deserved but why the commercial for LN Engineering? Every problem mentioned has a solution from many vendors nearly all equal to or better than LN yet all at a better price/value. LN is known for their fear mongering, dominating the forums, denying their own failures and colluding with indies so they will only sell their over priced products requiring much more labor in the process. This article comes across as part of the LN cartel as if the author made a call along the lines of “hey LN, cut me a check and I’ll drop your name a dozen times”. Want proof? So many problems yet were ANY other vendors even mentioned?

    1. Yet another butthurt owner of a Porshe with an M96 engine. This engine is a turd. Ask anyone who actually works on or races Porsches for a living, not just us. If you understand engineering or have a lot of experience with engine building you will understand. M96 owners are angry that their chariot has been called out and definitive facts about how bad the engine is have been presented. For your information, we have no affiliation with LN Engineering nor do they advertise with us or pay us in any way.

  31. While some of the criticisms are warranted, there were a few things I found baffling, particularly with the Intermediate Shaft System comments.
    First, no mention of an actual intermediate shaft failure, which is when the sprocket slips on the shaft. Th is obviously different than the IMSB failure, which is the more common failure of bearing itself.
    The second surprise was the comment on oil leaks. For sure the RMS is a problem leaker, so but badly that the engine runs out of oil? That’s a new one to me? Where else are these huge leaks?
    And finally, I’m confused as to how a failing IMSB could cause an oil leak. Even assuming that the bearing would hold up for a while running with enough wobble to damage its own seals, how would this translate to an oil leak? The bearing and its seals are internal; the aftermarket replacement bearings don’t even have seals! Are you postulating that the failing bearing would have enough wobble and last long enough with that wobble to wiggle the IMS cover loose? That seems very far fetched and certainly not a common issue.

    Full disclosure: I run an M96 3.8 in my 997 that failed at 70k due to stuck rings (poor quality oil, as the PO used it as a daily and thought Jiffy Lube was a good idea). I rebuilt the engine myself, so while I’m not an expert, I suspect I’ve been a bit more intimate that most replying to this article.

  32. You say you’re a Pro Engine builder… what have you won with your engines?

    Your write-up comes across as a butthurt person who can’t afford a Porsche, so you attempt to rip to shreds the Porsche engine.

    The replies demonstrate how little you know of the M96 engine.

    1. We have won a lot of things with the engines we built. I am in fact a Porsche owner. You are commenting across as a butthurt Porsche owner that can’t come to grips with the fact that you bought the wrong Porsche and is butthurt that the value of your car has dropped like a Rock, even when presented with factual evidence.

  33. I just stumbled upon this article. Sweet Cheeses it is full of inaccuracies and misinformation. So many people have tried to correct the author, and he just stumbles and yammers through the same BS as a response. Ugh

    1. Another comment from an insulted indignant Porshe owner that knows nothing about engines that can’t admit he bought Porsches worst engine, even when presented with objective evidence. Opinion beats logic every time.

  34. As a technician of 40 years and a Porsche 996 owner I can say that all issues presented here by the author are absolutely factual. As far as these cars being worth $30 K after 20 years, remember you started out with a $100 K plus vehicle. And yes there are a large number of owners that have driven many thousand miles problem free, however that still doesn’t negate the fact that these engines are prone to numerous issues.
    LN and JR have spent a LOT of money banking on this and I’m sure that they will be repairing these engines fa into the future, not to mention that they have now started buying up dead vehicles to harvest parts from.
    IMO Bore Scoring is by far one of the biggest issues with these vehicles, not to mention cracked heads or snapped head bolts. The reason we see this more in cold climates is that owners store their cars for the winter without regular starts, allowing all the oil to drain away from the piston to wall area which leads to a dry start up condition. Once you tear through the Lokasil coating it’s only a matter of time until a very very expensive rebuild. Don’t believe me, just look at the prices people are asking for engine parts these days, if you can find them. My 996 was pristine with 57 K, the apple of my eye until one day while waiting for my IMS bearing I decided to remove the spark plugs and send a bore scope into the cylinders. Cylinders 5 & 6 were scored and 4 was about to join them. Although scoring starts at the base of the cylinder it almost always visible as deep scratches all the way up the bore. Anyone considering buying one of these vehicles should always have a comprehensive PPI performed which includes scoping the engine and owners should always include this as part of spark plug replacement as it only adds about an hour to the process once plugs are removed.

  35. Great article, and the commewnts are something else !!
    I was abou to buy a 2006 2.7 boxster.
    even though this year & size seems to be ‘safer’ theres no way im touching it now as its been a garage queen & only had normal services. no actual fixes.
    i’ll look for a 9A1 powered one.

  36. I bought a 02 996 (65000) I knew about the IMS .I checked the oil filter all the time I drove it planning to replace the bearing with an oil fed Ims solution and it went about a month before I did it (72000).I’m was so distraught. luckily the engine wasn’t destroyed .I disassembled the engine myself replaced all the important parts. Cleaned out the pile of metal and ball bearings on the bottom. luckily nothing too damaged I knew about the death rattle and turned it off immediately maybe 2 or 3 seconds into it. the sound of it still haunts me to this day .but you’re right it’s a s***** engine. the cylinder walls come up to the head with no support it runs beautifully now but I don’t run it hard. I’m going to sell it and buy the newer .model with no IMS.all the people that are saying it’s a junk engine are correct. I think it’s a real poor design and I’ve built engines my whole life .it’s sad that Porsche would put ball bearings into an engine especially with the seals on it. what a mess I had to deal with. running great now though(110000). Now I’m afraid the cylinders are going to go or something else. I also have a 74 Targa I rebuilt years ago and the engine does have an intermediate shaft but it’s gear driven from the crankshaft ,better design oil fed. For all those naysayers ,
    it’s not if but when.

  37. Well, the World is full of people that write stupid things, simply naming these fake news writers.
    We have one here, he is an “independent”, ..paid by Nissan !
    What can you expect ?

    If he would have written about Ferrari, he would have said that F engines are shit, because in most of the recent models, you have to change the belt (yes, F engines have rubber belt driven cams, ..and even in some models, you have to take the engine out to change that belt !)
    Then what ? I suppose that the same “writer” do not even know what is a F car !
    (If he knows, then can we imagine what he would say about an F engine ???)

    Yes, M96 was the first water cooled P engine, ..and it is not perfect. By the way, humans are not perfect either, (..we have a great proof here that is by far not the case !
    It is true that Einstein was used to say : “I think I know at least two cases were we can talk about Infinity : The Universe, and the human stupidity”, and then, he would add “well, for the Universe, it is true that I still have some doubts !”

    Sure, I did own few cars with M96 engines. When I bought the one that I currently have, I asked if the IMSB has been changed. Answer was no. Then, I reduced the offered price by 2k (my rough estimate of the cost to change the IMSB), made the deal, and then, the very first thing that I did was to install a double row pro (ceramic) and paid the 2k.
    Where is the problem ? If you are not able to assume a maintenance of this amount for this kind of cars, then forget about these,, ..and buy a Nissan, you got a cheaper one, and this should better match you way of thinking.

    If you agree to change a rubber belt on a regular base (much more often than changing an IMSB on a P car !), then, buy a F car, they are great and have beautiful engines ! But do not cry like a little boy that lost a wheel of his dinky toy after forgetting any belt changes and having an engine failure.

    And if you buy such type of cars (M96 based) and do not know that you should think about this particular maintenance, then frankly, I’m sorry.
    You better should buy a new car and count on the warranty, hoping that at least, you will know that you should verify oil level and tire pressure on a regular base !

    Or, two cents about such stupid article written by an immature person that names itself “journalist”.

    1. Your replay is totally based on emotion with no clue about the design and drawbacks of these engines or engines in general. The IMS shaft is just one of the problems that plague this engine. If you have a later version, changing the bearing is more than a $2000 job because you must know that the engine has to be removed and the cases split. If you change the bearing, what about oil starvation, bore scoring, D-Chunk failure and I can go on and on. You are incapable of looking at data, physical evidence, and facts. You also have no clue as to why there is a thriving aftermarket for fixes for these engines. Not modifications for more power but simply fixes to get them running and to do rebuilds that are longer lasting than the original. Ask any Porsche mechanic if they think this is a good engine! Sorry to insult your golden chariot extension of your manhood but the engine is a poor design.

  38. Hi Mike,
    I bought a 2000 Boxster S last fall, with 90700 miles on it, well aware of most of the issues raised in this article, and I have a question for you:

    I have replaced:

    IMS – LN single row pro / RMS / complete clutch
    AOS/water pump and reservoir
    cam chain tensioners and slides (the VarioCams are good) with reset timing
    major servicing
    complete brake and suspension rebuild

    So my question is: is there anything else I should be doing to get this engine in its best shape? Sump pump?


    1. Presuming that you are just street driving, this is a very good start. Be mindful of spotting bore scoring. I think frequent oil changes can help with this.

  39. The M96 is unique to the Porsche world in my opinion because the dip in price allowed a lot of people used to building Mustangs and Chevys to buy into the market.

    Those folks – their eyes pop out when they see the estimate for a service.

    Thus, we get a whole lot of whining about the motor. But if you talk to traditional Porsche owners (i.e. rich guys) I don’t believe they’re so allergic to the expenses involved in hardening the motor. All Porsches benefit from hardening, none are perfect, and I doubt the M96 is all that more expensive at the end of the day.

  40. Laughable on so many levels.

    Statistics derived from people and firms that make a living on rebuilding engines.

    An author who has to defend his poor analysis with increasingly more dramatic numbers and statements.

    Perhaps the M96 has slightly statistically more issues than other engines, but these claims and assertions are just another example of anyone writing anything they want (often with a commercial benefit).

    Reminds me of my daughter trying to convince us that brushing your teeth has no benefit

    1. Why are so many of you Porshe owners with an M96 engine so arrogantly ignorant? It’s beyond me. Something is laughable and poor analysis just because it’s something you don’t want to hear. I have no commercial benefit from this. If you knew anything about Porsches, engines, engineering, or the surprisingly large industry that has sprung up specializing in repairing these engines you could easily make the assumption that these engines suck. Even if you don’t have any mechanical understanding which is obvious, pure capitalism shows that these engines suck. If there were few problems you would not have an industry catering to the repair of these engines because there would be no demand. If these engines didn’t suck, why is the value of these cars so low compared to other Porsches? The free market knows. As these cars age, a majority of them have an IMS shaft repair kit installed and soon many will be repaired for bore scoring. Read this again after you motor shits the bed.

  41. Very interesting article but my comment not relevant:

    I owned 7 or 8 (can’t remember) Porsches from 356 !955 Continental Coupe thru 1973 911 to my last 1978 928. All my records were destroyed in USPS truck fire in Reno, NV.

    Not withstanding some problems I loved my many years with all Porsches except the last 928 which I hated and sold two weeks after buying it. If I could have sat in it at Boston display I would never have bought it.

    Would anyone care to read my experience with Porsches over 23. years ? I have tails to tell that Porsche would never admit too.

    And one, not involving any Porsche defect, the most amazing time when being chased by police in Mass. I spun on the misting road and passed a Comet backwards at must have been 90. or so. But recovered and re-passed the Comet going forwards with the police still way behind and they never caught me.

    Charles M Schott Jr

  42. man, porsche owners are an interesting bunch.

    im almost tempted to go into some of your k20 articles and start arguing that the k20a3 motor is better than the a2 or z3 because it has vtec on the intake side and its reasons!

    (to be fair, the a3 motor is a good engine for what its intended for..a reliable daily driver and i love mine!)

  43. Hi, why is IMS issue so big in this thread? when its the bore score that IS the problem with M96 engines. IMS is easy and cheap to fix compare to bore score.

  44. Mostly because when this was written a few years ago, IMS failure was big but now that the cars are older, bore scoring is coming into play.

  45. I purchased my 2001 Porsche Cabriolet for just south of 6 figures, I did get the Hard Top option with my vehicle, but it is a total Pain to maneuver to a place in my Garage where it doesn’t get Damaged when not in use, which is most of the time.. In the roughly 15 years I drove the vehicle I put 73,600 Miles on the Odometer. I also put over $30,000 in maintenance before II had the IMS failure and what appears to be a large portion of a Cylinder Head show up in my Oil filter Casing. I have read many articles about the IMS Failure and had Porche people that have never had the misfortune of IMS failure tell me I don’t know what I am talking about when I said the Failure rate was around 10%. What a catastrophic event. I wrote a letter to Porsche about my experience and their only response was to remove me from their new product release flyers and such that they used to send to my house. The car was fun to drive though. My experience was always when driving in traffic, If you can see something, you can do it in that car. I started writing a song about my car, to the Tune of Life’s been Good by Joe Walsh – My Porsche Carrera, won’t even do 5, with an IMS failure, so now It won’t Drive.

  46. @Mike Kojima I own a 2004 40th anniversary edition with an X51, #0763. I bought it with 15k miles from a collector. It now has 40k miles. The oil feed is upgraded due to the 40AE mods. IMS was replaced, oil is changed every 3 – 4k miles. I drive it fast and hard and also slow and easy in the city. Top speed is 185MPH. I don’t need to go any faster than 160. The belt was just replaced due to wear, and all ignition coils were just replaced (along with plugs) due to two coils being cracked and a moisture issue. No other problems. The handling is tight, performance is high, it’s very quick, very responsive, and represents a pure 911 design. The upgraded interior hugs me and the analog experience is much better than being overwhelmed with tech.
    I would only trade it for a 2010 Sport Classic.

    @Jerry Prater had a great response to @Mike Kojima. It reads ” Mike, given your dislike for M96’s, why not do something else for a living and enjoy yourself. By the way, I own a 2004 996 Carrera, 45K miles, have only had to replace the water pump, 10K miles ago. Sorry, you were mistreated as a youth.”
    Whether he’s right or wrong, the guy who wrote this piece is an angry, pissed-off dude. His responses to the counterpoints from readers are angry, defensive, and lacking in any kind of grace and self-control. His attitude is what set other readers off and created this shit show. When guys like him call us to meet out for a beer, we let it go to voice mail. So next time this dude publishes an article, let it go to fucking voice mail.

    1. It’s unfortunate that you are blind to facts and choose not to learn about your engine’s shortcomings and not believe them when presented. Some Porsche owners are something else.

      1. Since this article is a few years old and things have evolved (e.g. IMS bearing issues giving way to bore scoring ) has anything else cropped up on these engines as they age that isn’t covered in your article? It is a handy go-to list of ‘stuff to fix / check’ for rebuilding.

        My M96.03 is still running pretty well but I’m aware that at 105k miles it is time for a rebuild so might as well have some fun with plenty of aftermarket parts and a 4.1 conversion while I’m at it!

        1. The main issue on the higher mile cars is bore scoring. I am not sure this is a huge issue or just one of normal wear, just that people are spoiled with how most modern cars now last over 200k miles no problem. I would wait until your oil consumption goes up and or compression and leakdown starts to become and issue. Unless you just want that 4.1 liter power now!

  47. I think those cars have their place in this world and that place is not my garage.

    I can understand both points of view but someone saying the 986 is a blessing to work on is beyond me.

    From my experience dealing with cars from 356 to the latest ones nothing was ever logical or made sense.

    Everything was always a compromise due to stubborn rear engined car and flat engine design.

    To me the 996 felt as a better car vs the older ones so it’s a shame they messed up the water cooled design this much.

    Someone mentioned Ferrari engines being even worse but I don’t recall anybody ever religiously defending the reliability of those in comparison to the Porsche fanbase doing it all the time.

  48. Holy shit what a back lash! 😂
    I worked as a tech for the dealer when the 996 was just released so I had my share of experiences with old and new cars. The air cooled engines constantly needed to be resealed due to the oil leaks from the cam housings at the heads and cylinder orings leaking at the block, or broken head studs or air ducts for heating the car off the exhaust manifolds.

    Crazy thing is, I’ve seen 964’s and older type 911’s sell just as cheaply in the past as any 996 has and it all just seems quite normal that most 911’s, with exception to the 993, seem to drop clear down to the $9k to $11k range if the mileage is anywhere near the 100k mark and the car is 10-15yrs old. Then they gain value again as time moves on. I had multiple occasions where I could’ve purchased 964 cars or 911 cars for less than $14k. Good condition cars. I’m kicking myself over it now but I think the drop in value is just the way these cars go from expensive to cheap and then ironically, back to expensive.

    I currently have a 996.2 (02 model) and I drove the crap outta that thing up until recently. 137,000 miles and still on the original ims. I parked it up because it’s due to be gone through. I already put an alternator and water pump in it, and promptly, I purchased the LNE wet bearing conversion kit with special tools for it, a new clutch, a rear main (even though mine isn’t leaking), an AOS, an oil filler neck (because the oil and heat make them brittle as hell), an expansion tank, (because they are notorious for cracking), and various vacuum lines.

    The last thing I have left to buy are the camshaft lift and timing actuators, as I suspect that the sitting has caused a clog to develop in one of them which caused the most random miss-fire I have ever experienced here recently, after a start up and drive around the block. It wasn’t an issue prior, but you know what they say about cars and sitting. I’ve had decent luck, but I remember the issues you speak of first hand, about 5-6yrs down the line.
    I still love my 996 though.

    These engines are just complex, and while they have plenty that needs to be looked after; they are still decent for the duty they were meant to serve.

    People tend to forget that the 996 changed the direction of the entry level Porsche 911. They were no longer raw little sports cars that you took to track events to run lap times with every weekend. The suspension tuning and alignment settings from the factory will tell you that they were geared more towards GT than actual sports car.

    Everything was softer, more supple and just plain benign in the 996 compared to previous models. You can actually drive a 996 for 8hrs and it wouldn’t abuse you. The earlier cars don’t do this so easily.

    With each evolution the base cars became bit less direct, and a bit more forgiving, and if you wanted to experience the old car’s personality wrapped up in a new model; you had to move to a 996 GT2 or GT3 which brought back more aggressive suspension and engine configurations that were actually meant for track duty.

    I personally think that’s where Porsche made their biggest mistake in the quest to lower the production and development costs associated with the base 911 production in general.

    Why track develop the base model cars, when most people aren’t gonna track it anyway? You want a track focused 911? Buy our GT2/3/RS variants which are specifically engineered to do this repeatedly with less adverse effects. The use of the Metzger platform in the performance variants kinda proves that was their thinking here.

    Bottom line is the base 911 started catering to long distance driver comfort and daily use, where as older base 911’s were always more sport car first, that if you could handle it, would be flexible enough to drive for long distances or daily commutes.

    I also noticed a lot of people saying the M96 was the first water cooled flat six that Porsche produced. That accolade actually belongs to the legendary 959 which had water cooled heads and air cooled block and cylinders. Hybrid cooled if you will, but still the first production run 911 based flat 6 engine with water in it.

    Great article by the way. I know it’s a tough pill to swallow for many, but I believe that it’s because we love our old 996 ‘s despite any shortcomings they have. People just take it personally, but the truth hurts worse when you’re in love. 😭

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