Thermostat

Saturday, November 11th: I had known for a few weeks that the thermostat housing in my E39 was leaking coolant. I could see areas of dried coolant itself on the plastic housing and small spots on the fan blades beneath the thermostat.

I am getting experienced with the front of my engine and the process of removing the fan shroud and fan clutch is becoming second nature. However, this doesn’t mean that it isn’t a pain, and it is. Once the fan shroud and fan clutch were out of the way, I quickly unclipped and unbolted the thermostat and replaced it with a new Behr unit.

I torqued down the bolts holding the new thermostat on and made sure everything was tight. I then put the fan clutch and shroud back into place, after which I bled the system. This was pretty easy, as I also had to do this when I removed my water pump shortly after I bought the car. All in all, a successful job that saved an unnecessary flatbed trip.