Update on starboard engine, one last attempt at diagnosis before pulling engine to save time and labor. Head gasket on 1,3,5 and 7 was bad, had a open area between 3 and 5. Replaced head gasket and engine will start up easily and idle, exhaust manifolds were getting hot 180 range so I shut off engine and allowed to cool for a period of time. Checked coolant at thermostat cap, coolant was not visible so began to fill with 50/50 mixture and it took 1.75 gallons to fill to top. After starting engine again at idle rpm for 5-8 min I noticed the exhaust manifolds were beginning to get hot again. Checked coolant level again and once again its not visible. No evidence of coolant in bilge or in the oil, collected water from exhaust into clear container to see if coolant was escaping through exhaust. Exhaust water was clear after allowing to sit couple min, was kind of white at first. What temp should exhaust manifolds be at idle, using a laser thermal gun to measure. The cooling system is "Full Fresh Water Cooling"