detroit 651 diesel eng overheating!

[delgao]

Hi, I have a problem with 1 of my engines that is overheating.I did checked the heatexchanger ,the manifolds,the raw water pump, the strainer and everything looks nice.Can anybody give and advice on this problem , troubleshoting list that I can follow or a hint,overlooking: something?

 

[Luhrs28]

Re: detroit 651 diesel eng overheating!

You didn't mention thermostat. I would check or better yet replace it.

With fresh water cooling there are 2 cooling "loops". The one circulated through the engine by the engine's water pump, and the loop circulated through the heat exchanger by the raw water pump. Both need to have adequate flow. You can check the raw water flow by looking at the water going out the exhaust.

To check the engine water flow is trickier because that water is very hot and you don't want to get burned. I would probably temporarily install a Tee somewhere with a ball valve so you can open it for a few seconds to check the flow rate. (with the engine warmed up so you know the thermostat should be open). Sometimes weird stuff happens, like the impeller falls off the pump shaft.

Also check for a blown head gasket. There are various ways, but one easy check is feel the hoses and see if they're getting rock hard with the engine running, indicating compression is pressurizing them.

Also check the heat exchanger's efficiency by measuring the temperature of both loops before and after the heat exchanger. Both should go into the exchanger hot and exit cool. Compare the readings to your other engine.