Oil coming out of water reservoir overflow

[msitework]

I was driving one of my M925's to town with my daughter to pick up one of her friends when I got a strong smell of oil and coolant. I pulled over and popped the hood and oil was coming out of the water reservoir. I then checked the oil and it was barely showing on the dipstick, I put 6 quarts of oil, which filled it up, and limped home. It never overheated, never lost oil pressure and it ran great. Can someone help me figure out how to fix the old girl, its a 250 cummins. Thanks in advance.

 

[doghead]

I'd bet your oil cooler failed.

It's fairly easy to replace.

 

[jw4x4]

Replacing the oil cooler isn't too difficult of a job. It's flushing the cooling system that's a real pain.

 

[msitework]

That's good news, I had a local mechanic tell me it was either a cracked head or cracked block, which I was really not happy about. Does anyone know what TM covers this, I tried looking but wasn't able to find it? Is this oil cooler in the radiator, anyone know the best place to get one? Thanks again guys.

 

[doghead]

Here is a picture from the parts TM. The actual cooler is part#5.

It is located on the passenger side of the engine, under the thermostat housing.

 

[doghead]

A new replacement cooler should be available through Cummins. The part number is on the next page of the parts TM.

A search of this site for the part number, should find some relevant reading.

JW4x4 posted how he tested his cooler.

 

[1 Patriot-of-many]

Well this is timely. My "new" 923 has oily looking coolant, but check of my oil dipstick looks good. Is it possible a soldier poured oil in the coolant? My truck only has 5400 miles/300+ hours on it. Find it hard to believe the cooler is spent but of course possible. Should I just have the coolant flushed and refilled and see if it reoccurs for starters?

 

[doghead]

Time and chemical reaction is the culprit. It has nothing to do with hours/miles.

 

[flibob]

When you get the new gaskets for the oil cooler the metal gasket has a bevel on it that is very confusing. Make sure they explain how it goes on and you understand. When I picked up my 932 it ran hot and had some oil in the coolant. Changing the oil cooler did the trick. I was told to use dishwasher detergent to flush. Flush till the water is clear. If your truck has the old orange hoses check them on the inside. Mine had wire on the inside that had rusted into junk. I think there are several threads on this subject with good info.

 

[jw4x4]

My oil cooler failed on my m932 with 600 miles on it. And that's not a rebuild, but original miles. The oil cooler housing is held to the engine block with 4 bolts. The first time I installed the housing, the gasket slipped out of place and did not seal. A tip is to take 2 bolts that are at least 1 inch longer than the original bolts. Cut the heads off the longer bolts to make them into studs. Thread the studs into the block and it makes it so much easier to install the housing and keep the gasket in the properly aligned.