Do i need to use gasket sealant when changing the thermostat and thermostat gasket on my car?

It is recommended to use the sealant, but in a pinch you can put it on with just the gasket that came with the thermostat. Now if yours is one of them that has an o-ring then no do not use any sealant, just be careful when putting the thermostat housing back on.|||for best results always use a good gasket sealant and gasket especially on chrome plated goose-necks.|||sometimes you do, but alot of gaskets these days seals themselves. if its got a 0-ring, you dont use nothing.|||just a gasket will do!|||In a word, YES. No other sealant will work as well under heat and pressure.