Thermostat replacement

#1

When replacing the thermostat and the subsequent need to replace the housing gasket, should you use HTV gasket maker in addition to the thin gasket? Can you over tighten the holding bolts, if you don’t know the torque specs say as you could on an oil pan gasket?

#2

It’d be a good idea to use some form of gasket sealer on the gasket.

If you over tighten the bolts they will surely break. Thermostat housing fasteners are particulary prone to breaking because they get hot and cold so frequently from their close proximity to the coolant. The frquent hot/cold cycles makes the bolts hard and fragile. Be careful not to overtighten them.

#3

JayWB: Thanks, ggrakerdink.

#4

Just make sure both surfaces are perfectly clean and use a product like Gascacinch or Aviation (made by Permatex) gasket sealer, they primairly keep the gasket in place.

Make sure the bolt threads are clean (better replace the bolts) and make sure the threaded holes are clean from debris and chase the threads with a bottom tap. It is very easy to over torque these bolts and dirty threads and debris in the holes make accurate tightening of these bolts difficult