Surprise found when replaced thermostat

[homepagz]

My '92 300D has ran cold since I bought it about a year ago - and now that the cold temp's are here it was clearly an issue with the thermostat.

Pulled the thermostat yesterday and found the PO had gutted the thermostat. Nothing there but the outside housing with rubber gasket.

Anyway - new thermostat is back in place and the engine is operating at the correct temp now. And the heat works - nice in this weather.

-John

[DieselPaul]

Feels good to fix stuff right, good find!

[pwogaman]

Well at least you have flow through for flushing the system now.

[jay_bob]

I think the PO had the opposite problem - he had wide open flow all the time.

That is a redneck repair for an overheating engine caused by a theromstat that sticks shut.

If the thermostat is stuck open, the engine never gets up to full operating temperature. This is actually a bad thing, since the oil never gets hot enough to boil off the dissolved water (from condensation, blowby, etc) in the oil. Also the engine is not at the proper temperature for efficient combustion. And your wife/girlfriend is unhappy because you don't have enough heat in the cabin.

If the thermostat is stuck shut, then you will get up to temperature and then the temperature will continue to run away, since the coolant does not make it to the radiator.

But as pwogaman said, keep that butchered thermostat, it is great for when you are flushing the system. Just don't forget to put a proper thermostat back in when you are through.

[tangofox007]

Originally Posted by jay_bob

That is a redneck repair...

"Repair" might be a bit optimistic.

[sixto]

No offense intended but you're talking about the engine end of the lower radiator hose, right? There is no thermostat in the conventional engine end of the upper radiator hose.

Sixto
87 300D