Imperfect Fleetside

Ok so my heater is not getting that warm and at times its just flat out cold so i added coolant and it didnt help so i got a thermostat for it without the gasket so my question is. Can i just use silicone RTV sealant as the gasket itself or must i get the gasket and do it that way? Sorry i pressed teh wrogn button for the F150 in the title.

nauss85

I would get the gasket. If you are in a bind (cant get one, dont want to pay, cant get out to get it) then use the RTV...