Here we go:

98 528i thermostat part # 11537511083

I have a thermostat for a 95 M3 which is part # 11537511580

Are these interchangeable? I think the only difference is the M52 thermostat kicks on the fan at 92 degree celsius while mine kicks it on at 88 degree celsius.

Am I right, am I wrong? Can I use the S50 thermostat in the M52?

thanks.

bump

Are they interchangeable? No.

Could you use a lower temp thermostat in the M52? Yes.

I wouldn't do that in a NY car because it will reduce the available cabin heat. And it will slightly decrease engine efficiency, resulting in slightly lower mileage.

I don't believe the thermostat has anything to do with when the fan comes on. That is controlled by a fan temp sensor. I also agree that they are NOT interchangeable.

I don't believe the thermostat has anything to do with when the fan comes on. That is controlled by a fan temp sensor.

This is correct.

thanks everyone.

havent had time to research because of very limited acces to the internet lately.

I appreciate you all answering my question that I obviously never researched.