Twin 5.0 mpi's, 1 with low temp?

Marcdohc

So My 05 300 with 5.0 MPI Merc's seams to run fine but the starboard one stays cold and when the port side reads 180* the starboard side reads 75* to 100*. Any ideas whats wrong? Thanks for your imput, Marcdohc

Black_Diamond

Could be a stuck open thermostat..or the gage/sending unit is bad..or bad wiring.

Marcdohc

Thanks for your reply. Is there a way to unstick the thermostat without taking it out?

Black_Diamond

If it is stuck, it needs to be replaced. Cheap fix!

Capt Ron

Same thing happened to me last year....changed the thermostat and everything is fine now. I also noticed the starboard engine takes a little longer to warm up than the port engine. I think this is due to the hot water tank heat exchanger which is connected to the starboard  engine cooling system. If the hot water tank isn't heated, it will take a little longer for the thermostat to open up.

212rowboat

same principle as a heater core in a car, Capt Ron... the added heat exchange surface when you open the circulation (in a car, you've turned on the heat) keeps them cooler, and warming them takes longer.

Marcdohc

K, Thanks

TonyWalker

Just a guess on my part.  If the thermostat is wide open causing the engine to run way too cool, you might also notice the oil pressure is a bit high.  Cold oil, higher pressure.

Tony

Salt Shaker 342