This car came in overheating and missing badly. Customer was very concerned that the engine was OK, and wanted to be sure it would run right when we were done before we repaired anything. Mostly the engine was missing because coolant had soaked the wires and coils. We replaced the wires and plugs and dried out the coils and it ran fine.
Overheating was an easy diagnosis since this is what I saw… What your looking at is the coolant manifold on the rear of the head. It has two places that would hold a temp sensor, but the 2nd one is plugged on this model. The middle of the plug is busted out and you can see it full of antifreeze.
When I pulled it off this is what I saw. The hole wasn’t broken, it was melted.
Anyone with some Volkswagen experience knows why these things overheat. See the red dot in this pic? This is where light was passing through the plastic from how thin it had melted.
And of course this is why it was overheating. Plastic impeller broke off. Customer had gotten it HOT! Causing the plastic to melt into globs. These folks were lucky they didn’t end up needing a motor after this. Water pump is driven off the timing belt, and this car was overdue for both.
Complete timing belt job on this car consists of..
Timing belt and tensioner.
Metal impeller water pump.
Cam position sensor[/one_fourth_last]
And when you’re done you end up with a reliable car again, and you don’t have to worry about pistons hitting valves.