Hi,

I've had this problem for a while now and am wondering what is the main cause. The car regularly runs between 90 and 95 C on the highway; hotter the faster I drive. Yesterday I pushed it up to 100 C going up a hill at 70mph I drove my wife's 300D-T up the mountains a month ago going about 70mph and that car stays around 85 to 90 C no matter what.

I changed the coolant (zerex) and replaced the thermostat 10k ago, but no improvement. Now that I want to increase the power, I really need to fix the problem.

Is it fouling of the radiator with deposits, or could it be an inferior water pump? The P/O replaced the water pump before I bought it and the receipt was from Checker...probably some cheap knockoff part. I also was going to try the true flush method (degrease, citric acid wash, rinse, M-B coolant) but was wondering if it was the water pump. Anybody have ideas??

__________________
Dave

2002 Audi S6 Avant
1983 300D
1984 300D (sold)
1990 560SEL (sold)