“My Girlfriend's” Miata: Part 5 – Keeping Cool with Koyorad Radiators
I had a dream. In this dream a man would drive a car on the track. He wouldn’t own this car, yet he would have all the joy and happiness as if he actually owned it. His expenses would be low and his debt modest due to his loving girlfriend’s trust and/or gullibility. This was a beautiful dream that would leave me slightly sad when I awoke. Surely I couldn’t become this man. With my awkward personality and face only a mother could love, no girl would date me, let alone be foolish enough to let me drive her car at speed. But this my friends, is America. Dreams still come true and slowly, the dream has started to become a reality. First the girlfriend, then the Miata, then the rollbar, seats and brakes to get it track ready. The last piece of the puzzle was improving the dumpster fire Mazda calls a cooling system in NA Miatas. With the help of Koyorad, my vision, foretold many years ago, is ready to be fulfilled.
So why does God’s greatest gift to humans, the NA Miata, have a terrible cooling system? The story starts long ago when Mazda decided to base the 1.6L B6ZE engine for the Miata on the 323 GTX Turbo’s engine, without the turbo. This sounds all well and good, and honestly it is for the most part. The engine was an improvement over the standard Mazda B family design. With a stronger block and oil squirters to keep the pistons cool, Mazda then went with lighter connecting rods and a lighter flywheel, to give the engine a nice, sporty vibe. Unfortunately for the cooling system, they sort of forgot that the engine was transverse in the 323 when the placed it longitudinal in the Miata.
What had happened was, in the front wheel drive layout of the 323, the coolant ran through the engine front to rear, working just perfectly and cooling the entire engine evenly in the process. In the Miata, apparently front to rear was not an option and the system was routed bottom to top… on just one side of the engine. This leaves the back half of the engine significantly hotter than the front. Mazda later designed a head gasket that forced more coolant through the back of the engine, but only for the 1.8L block models. On top of that, our radiator was seeing better days with cracks starting to appear on the plastic end tanks. These were just waiting to snap at the first sign of stress, not unlike Kanye at an awards ceremony.