In Reply to: Re: A/C 535i and Aux Fan and Temp problems posted by DJDolan on June 29, 1999 at 16:14:30:
If you have build-up it could be due to not using antifreeze free of silicates and phosphates, as in the OEM antifreeze. It seems to have been a common issue on older BMW's.
: Just today my 535i overheated again. Two weeks ago, and one year before, I had towed to machanic. Both times the thermostat was replaced. This time, the mechanic thinks its the radiator -- says that it has become less efficient because of build-up on inner piping. Could this be so?? (The problem has occurred during the summer, and only when I have had the a/c working -- placing extra burden on the system). Could the problem be the two speed auxillary fan not working at both speeds, or, the "clutch" instead?? Sure need to know soon -- the mechanic has ordered a $400+ replacement radiator (which can be returned) -- plus labor charges.
: Can anyone please suggest some 11th hour checks which should be made before replacing the radiator -- and later finding that it wasn't the problem? (Car maintains temp just fine when driven without the a/c on.) Many many thanks for your help asap. DJD/Louisville KY