M931 Overheating

[Clayshootr]

I have a M931 with the 250 Cummins in it. It has warmed up on me a few times. The coolant level is up and the belts are good and tight. I did not think the fan was kicking on so I installed the two bolts to lock the clutch up so it now runs all the time but still gets hot...

Just wondering what the first steps are to figuring out what is going on??

Should I flush the cooling system and install new thermostats and see what happens? The truck was rebuilt in 2007 and had 5 miles on it when i picked it up last winter so the radiator looks like brand new...

Thanks for any advice!
Tj

 

[colelkhunter]

Before you do anything else. get a laser thermometer and shoot the engine block and radiator. Mine started with the same thing. turned out to be the guage or sending unit reading wrong. Motor was cool as a cucumber, temp gauge was hot.

 

[M35A2-AZ]

Also is the fan coming on?

 

[goldneagle]

Also is the fan coming on?

He said he locked the fan clutch with the 2 provided bolts so it turns all the time.

 

[romanservices]

My M923 was overheating similar to yours. The Fan actuator valve was not working so I replaced that. It was still overheatig and there were hot and cold spots on the radiator. Fearing that I needed to pull the radiator I decided to replace the thermostat first. Now the radiator temps are all even and low, using a laser temp engine is nice and cool however temp gauge reads a little over 200. I think the sender or the gauge is needing to be replaced next. I'm confident that the engine temps are normal no matter what the gauge says.

 

[M35A2-AZ]

He said he locked the fan clutch with the 2 provided bolts so it turns all the time.

Sorry I read that, then forgot it.

 

[Csm Davis]

Before you do anything else. get a laser thermometer and shoot the engine block and radiator. Mine started with the same thing. turned out to be the guage or sending unit reading wrong. Motor was cool as a cucumber, temp gauge was hot.

Okay this needs to be put on a sticky or in the wiki I know of five Steel soldiers that have had this same problem and many trucks at Camp Shelby that have done the same thing it is common enough that I keep a laser thermometer in my toolkit for recoveries.

 

[Bolkbich]

My M923 read high on the temp gauge, laser said 160 deg. I changed the sender then the gauge, still read wrong. I installed a mechanical gauge ...much better.

 

[rrrr]

I had an issue with my temp sender and gauge. I replaced them both. I tested the temp sensor according to the TM. Replaced it and things looked good for a while. After driving the truck I went out the next day to find the temp gauge still reading the shut down temperature from the day prior. I banged on the gauge and it went to 0. After I replaced the gauge no issues for the last two months. You need to make sure you are not truely overheating. A laser thermometer is a great way to make sure. Good luck. Oh, my truck came from Camp Shelby !