how do i replace the thermostat

Follow top radiator big hose from radiator,there will be a housing at the end going in to motor,shoudl be two bolt,s there,remove them and thermostat is under it,make sure when you remove it to take note that spring go,s in motor ,downward,clean housing good,and around where it set,s,then place new gasket and thermostat,replace housing and hose,,,hope this helps,Good luck with it.

I'm replacing the thermostat on my 1991 Chevy S10 pickup 2.5 liter my question is do I put gasket sealer when installing