Where is thermostat on 2000 Saturn LS2 3.0 engine?

Answer 1

It is on the engine block, but to access it you have to remove the upper manifold & runner, lower manifold, and the spacer to get to it. If you are replacing the thermostat, you will need to get a new housing, because the new thermostats don't fit quite right for the LS2 3.0 liter engine. You will also need to get new bolts for the thermostat housing. The bigger star head bolts found on the spacer and lower intake manifold will fit, but you'll want to use them as a sizing guide. You can get new bolts at most local auto parts stores. You will want to be careful when taking out the metal tube that connects the thermostat to the upper radiator hose, because the flange that bolts it to the engine block is somewhat fragile (i.e. don't use a crowbar as a pry-bar to get it loose).

Where the bottom hose meets the block.