M-25 Engine runs a cool 130 degrees

[Jerry Maisonneuve]

I have 1984 Cat 30 with the M-25 diesel. It runs fine but the highest engine temperature is 130 degrees. The temperature guage has been checked and a new 160 degree thermostat has been installed. The owners manual says the operating temperature should be between 165 and 190 deg. F. Any comments would be appreciated.

 

[Jack Bollinger]

Engine Temp.

Hello Jerry,Have you checked the coolant temp. using a thermometer? A quick check with the wife’s digital thermometer may help, if you havent tried it yet. I have a 1983 M-25, It runs great. When I first bought the boat I had the same problem. I went through all kind of ideas and ($). It turned out that the wire from the sending unit to the temp gauge needed replaced. The temp was 165 it just didn't get the complete signal to the gauge. Good Luck,Jack