At 10:03 AM 1/12/2002 +0100, you wrote: >- My guess would be the problem is a leak in the heat exchanger in the >bottom of the radiator. When warmed up, there is greater pressure in the >radiator than there is in the coolant lines and exchanger so the radiator >solution enters the exchanger but trans fluid does not enter the radiator. >i'll take the radiator to a radiator shop to check it. The theory sounds >good but when the engine is stop, does the trans.fluid couldn't >contaminate the coolant ? And if ther's a leak in the exchanger, the >trans. fluid would be higher than normal. On the car the trans. fluid is a >the correct mark. When you turn off your car, the coolant temperature rises from residual heat, and do does the pressure in the cooling system. In the same time, since the transmission pump is not moving, there is no pressure in the transmission lines, so this would be the time of highest pressure differential and highest leak from radiator to oil. Even when the engine is running and the tranny pump is turning, I doubt there is any restriction in the return of the cooling line, so there is very low pressure in this line (even though there is flow). About the fluid level, you have a good point. It is possible though that the leak is very small and some/most of the water evaporates, but not before it does its damage (remember, the oil does get quite hot, probably hotter than the boiling point of water). D^2