Project Hyper-Miler Part 2: Maintenance


Ensuring you maintain proper timing for the camshaft and injection pump is both a blessing, and a curse on this engine.  Rather than put marks on the belt and pulleys to determine proper positioning of all pulleys, VW designed the crank, camshaft, and injection pump to be locked down with a specific set of tools.  This is a blessing in that as long as the lock tools are installed properly, a blind chimp could change the belt without messing up the timing; and a curse in that you need to use special tools to perform this task.  Once again, the TDI community has come to the rescue, as the tools are available for purchase or rent from a number of sources. 


Thanks to the TDICLUB community we didn’t have to purchase the tools necessary to lock down the cam timing and were able to simply rent them HERE.


Do not, we repeat, DO NOT, trust marks to properly time the engine.  The main problem with this method is as you tighten the tensioner, the pulleys move with the belt, changing the timing.  If you lock the injection pump and camshaft pulleys, the crank will move.  If you lock all three down, you’ll probably break the camshaft.  To counter this, VW’s method is to loosen the injection pump pulley (which has slotted holes) and the cam pulley (which has a tapered seat and no key) to allow for pulley movement when tightening the belt with the lock tools in place.  Since the keys have locked the actual camshaft and injection pump properly, the relative position of the pulleys is inconsequential.  As we said, once locked down, it’s nearly impossible to mess up the timing of the engine.

To finish things up, we enlisted the help of a VCDS HEX-USB+CAN cable and software from Ross-Tech.  The VCDS HEX-USB+CAN is an invaluable tool that can be used on nearly any OBDII VW product to log from a database that includes over 14,000 fault codes and measuring blocks, as well as connect to other modules in the vehicle, such as the stereo, ABS computer, convenience, and anti-theft.  Once we had everything buttoned up, spun the engine by hand two full revolutions, and verified timing was still correct, we warmed the car up and connected the VCDS cable to lock down the timing slightly advanced.

If paying someone to do this job (we don’t blame you), make sure they are going to use the timing belt tools to lock everything down, as well as replace all TTY bolts.  There are countless horror stories out there of ruined engines due to not following proper procedures, even from VW dealers.


Project Hyper-Miler VW Volkswagen MKIV TDI Jetta Maintenance Engine Vacuum hoses
This mess of vacuum hoses can be a nightmare if you decide to yank them all out at once and attempt to follow diagrams.  We chose to replace one line at a time, resulting in zero issues or misrouted lines.


Since the TDI’s elaborate Variable Nozzle Turbine (VNT) and emissions system are controlled entirely by vacuum (through a vacuum pump, since a diesel makes no vacuum on its own), we decided to head over to to order new vacuum hoses.  We went with Vanguard part #s BKVP5054-13-10 (10′ of 4mm ID 50 DURO hose) and BKVP5054-22-10 (10′ of 3mm ID 70 DURO hose).  Simply remove one line at a time, replace with the correct diameter hose cut to the correct length and move on to the next.  Do not attempt to pull apart the spaghetti factory all at once and put it back together, no matter how many diagrams you have unless you’re certain there’s a routing problem.


Project Hyper-Miler VW Volkswagen MKIV TDI Jetta Maintenance Engine Vacuum hoses
Replacement vacuum hoses from McMasterCarr cost only $20 and will prevent headaches in the future from troubleshooting vacuum leaks.


The last step in resetting our maintenance clock was fluids and filters.  We ordered an IDParts filter pack for the A4 chassis VW TDI.  This kit includes a new OEM fuel filter, as well as MANN oil, air and cabin filters.  We topped off the crankcase with Shell Rotella T6 5w-40 synthetic oil, and filled the transmission with Redline MT90.  Filter changes seem to be the one area where VW made things easy for the guys working on it.  The fuel filter sits behind the passenger headlight with everything easy to reach, the oil filter is in a canister front and center, easily accessed from above, and the air filter is easy to change like almost all vehicles.  Since the brake fluid looked extremely sketchy, we bled and replaced the fluid with Motul RBF600.  While performing our timing belt maintenance, we also refilled and bled the coolant with genuine VW G12 coolant.  This is a lifetime coolant that does not play well with other coolants, so do not mix unless you enjoy coolant-flavored jelly. 


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