Originally Posted by strohausii
Make sure the ear'd rad. cap is on the high point above the turbo, the round cap goes on the radiator. The ear'd cap allows the vacuum back to the engine.
Seems strange that the coolant itself fixed the problem, did you find alot of build up w/ the prestone?
I know about caps because I spend a lot of time with this issue. (6 coolant flushes in the last 6 months.)
I could find many black precipitates in the reservoir when Prestone was in. Since I switched to Honda coolant, the coolant level is always within the normal range.