Thermostat stuck

[Goico9]

As I am replacing my cooling system, I got stuck with the thermostat itself. It seems to be sealed stuck with rtv. I’ve tried pulling and prying it a bit but am scared of damaging the engine block. Does anyone have any suggestions?

[UsernaM3]

Mine was also quite stuck after being there for over 20 years. Are you sure it’s sealant and not just old grime and the gasket? Anyway, what I did with mine was put a screwdriver through the opening that sticks out of the block and then rocked it back and forth with one hand on either side of the driver until it came loose. That way there’s no damaging the block and you can get decent leverage.

[jclausen]

Spray lube around the seal and tap it lightly