94 Crownline with 5.7 MCM Alpha (engine serial #OF281631) - I am replacing the thermostat, exhaust manifold and elbow gaskets. The manual recommends gasket sealant. The parts guy at my boat shop strongly recommended that I use grease instead of sealant. He said that the sealant will cook, become briddle and not form a tight seal with the two surfaces. Which one do you recommend - grease or sealant? Either way, I'm assuming you coat both sides?