M70 thermostat inspection and cleanup

When draining the cooling system in the 750i no fluid came out when unscrewing the radiator bolt. I stuck  a small screwdriver in the hole and out came radiator leak stopper. Yuck.

I then opened the thermostat housing to inspect thermostat. First of all it was installed upside down (the correct way is having the bleed nipple upwards) and it too was contaminated by the cement. I sandblasted the thermostat cover and sodablasted the thermostat. I also tested the thermostat in hot water to ensure proper function before re-installing it.