I am replacing the factory radiator with an all aluminum. While in there, I was going to replace the water pump with a Stewart. I figure that I may as well swap the t-stat housing to an aluminum as well as swap the t-stat. I saw different options for high performance use. They had different temperature ratings: 80C, 75C and 71C. Any suggestions?
Pick one according to your usage. The lower temp thermostat will allow the engine to run cooler but as a consequence, your heat may not be as hot in the winter. It's the opposite for the higher temp thermostat; your heat will be hotter in the winter but your engine will run hotter overall. I don't know why the other two are even options; I would go with the 75 (this is what I did with mine; chose the middle option). If you track the car, I wouldn't bother with the 80C thermo because a hot engine on the track = bad!
Thanks, my plan is to track the car. Doing all the replacements myself, is there anything I need to know or any tricks?
BUY THE CORRECT ONE. The lower temp ones are for M20s. The 95 M3 uses an 88C Tstat. THe S52 uses a 92C. The engine is more efficient at higher temps. If you are overheating at the track with all new cooling system components, you have other issues.
And I have found my water temp to be a needle width cooler on the semi-useless water temp gauge running an aluminum radiator. Another reason for using the correct t-stat, on those cold mornings you will want the motor to get to operating temperature. Edit: Also inspect the overflow hose that is under the fan shroud. Mine became loose due to a broken clip and rubbed against the fan. There is not much remove between the fan blade and hose. Now I have a cable tie securing it as a precaution. And since you are tracking the car. I have all my fender linings reinforced with cable ties near the brake ducts.
Thanks for all the insight. I am having to replace the radiator because the factory one is leaking. As far as a cold winter, I am not far from the gulf coast and therefore most of the winter is mild. For that reason, I would like to go to a cooler t-stat, 75C to 80C. I do think the 71C is too cool. The water pump swap is strictly preventative maintenance. I was NASA this weekend and another 95 M3 owner suggested to go ahead and make the change while I was in there. Thanks for the tip on the fender linings.
