Starboard temp increase

[BRHEAUME]

On my last trip, I noticed a 10 degree increase on the starboard engine gauge. This engine always heated up faster and ran (according to the gauge) 5-10 degrees warmer than the port. However, the gauge is showing 175, while the neck of the coolant filler, near the sending unit is reading 155, which is the same as the port engine. I replaced the gauge and sending unit - no difference. What else shall I look for?

[bud37]

Curious, How long has it been like this?

If you have this option, is the stbd. or port engine connected to the water heater ?

Check the thermostat itself, perhaps the engines have different thermos in them. there will be an approximate opening temp stamped on it somewhere. Unfortunately you will have to open the housing though, perhaps need a new gasket after.

[BRHEAUME]

It is connected to the water heater, yes. Just noticed this temp increase during my last inbound trip after about 20 minutes at 3200 RPM.

[Viper]

Could be a number of things. We should start with the engine make, model, and serial number.

[BRHEAUME]

Crusader 454xl (1995)
FWC
101999 is the serial
Impellors are 2 years old
New Water Cooler
Heat Exchanger flushed/cleaned last year

[bud37]

I guess the assumption is that you have been trying to find out for some time why one engine runs hotter and it has been like this since you have owned the boat judging by the cleaning / flushing of the heat exchanger etc.

Then on one trip back it climbed up 10 degrees more than before, if this is so then make sure your sea strainers are clear and the lids sealed tight if you have them. Also blow out the intake hose back thru the hull sea cock to make sure the line is clear and you haven't sucked up a bag or something therefore restricting the flow there. That can be done with a shop vac on blow, works real well. Verifying good cooling water flow thru the engines is always good practice and an easy to do first step.

[thatchh]

When were the exhaust elbows last replaced? I suggest you get an infrared temp scanner (they are pretty cheap online) and monitor the temperatures of exhaust elbows, manifolds and hoses while underway at your cruise rpm.