Uh, oh! Anti-freeze In the Oil

[dabtl]

I changed the oil today. It appeared some anti freeze is in the oil. The radiator also seems pressurized without it having been started in a couple of weeks. Not a lot of pressure just some.

Head gasket?

 

[bassetdeuce]

Residual pressure in the radiator can hang around for a long time. If you get antifreeze in the oil, but no oil in the antifreeze, I would suspect the oil cooler is bad/leaking. If there is oil in the antifreeze, or if antifreeze is being consumed/rapidly blowing out from overpressure, I would suspect a head gasket.

 

[11ACR-LT]

Can the oil cooler be repaired or does it need to be replaced ? My M35 gets a small amount of coolant in the crankcase also, maybe 2 pints in the high part of the pan, the oil never shows any sign of coolant mixing and the coolant is clean ( radiator and what comes out of the pan both)
Thoughts ?

 

[Nonotagain]

I changed the oil today. It appeared some anti freeze is in the oil. The radiator also seems pressurized without it having been started in a couple of weeks. Not a lot of pressure just some.

Head gasket?

DABTL,

How involved in the repair do you want to get?

You could remove each injector and look for evidence of antifreeze. While the injector is removed, pressurize the cooling system and listen for a hissing sound in the cylinder with the injector removed. If the hiss is detected, the head gasket needs replacement.

The oil cooler can be pressurized and leak checked.

Given the number of head gasket failures reported in the past, chances are good that the head gasket is the source of the leak.

 

[badgmc56]

If it was the oil cooler, oil would be in the anti freeze because oil pressure is greater than cooling system pressure. I would suspect head gasket.

 

[tiger422]

 

[bassetdeuce]

Maybe I got it backwards. Trying to remember what a former Army deuce mechanic told me.

 

[dabtl]

I am starting with the oil cooler. A new one from Memphis is on the way. I will order a gasket set from TNJ Murray if that does not cure the problem.

We had a similar problem last year on a M113 and the oil radiator was cracked. That required removing the engine and a complete dismantle because it was internal. This is at least accessible.

 

[dabtl]

Changed out the oil cooler. Simple task. Drain the antifreeze, no oil in it, move the secondary fuel filters out of the way, three nuts to remove, and disconnect the last three injectors lines at the cylinder head and bend the lines just enough for clearance. Took an hour or so.

There are two o-rings to replace, also. One, they were red, showed a black ring around its circumference which might indicate it had failed.

At any rate, now we just watch and see what happens next.

 

[rosco]

I have had oil coolers fail - always oil in antifreeze, and lots of it. After the replacement of the cooler, I flushed cooling system with dish washer soap, several times to remove the oil. Oil pressure is far greater then cooling system pressure. Gasket type failures usually go the other way. Antifreeze into the oil. When the engine cools, coolant seeps into the oil.

Lee in Alaska

 

[Mackfire68]

I had the oil cooler fail on my Mack Fire Truck, anti-freeze in the oil and oil in the anti-freeze. I presurized the cooling system and disconected the oil lines to the cooler. Anti-freeze poured out of the oil lines. Replaced the cooler and flushed the cooling system and changed the oil. Problem solved.

 

[dabtl]

DABTL,

How involved in the repair do you want to get?

The oil cooler can be pressurized and leak checked.

I had thought about pressure testing the oil cooler. But, how? It probably is quite simple and I am quite dumb.

 

[Nonotagain]

I had thought about pressure testing the oil cooler. But, how? It probably is quite simple and I am quite dumb.

Easiest way is to cap the inlet and outlet and submerse in hot water. The hot water will cause an internal pressure increase which will show bubbles.

This method has used in the aircraft industry for verifying that components are sealed from water intrusion.

 

[dabtl]

See I proved how dumb I am.

 

[RANDYDIRT]

If it was the oil cooler, oil would be in the anti freeze because oil pressure is greater than cooling system pressure. I would suspect head gasket.

Hmmmmmm. What happens when you shut off the engine? The oil pressure drops while the cooling system stays pressurized. Poof... instant antifreeze in the oil.

Dirt

 

[pwrwagonfire]

Had this problem before...was a bad head gasket

 

[dabtl]

I retrieved the old oil cooler from the junk pile and will test it this weekend for a leak. After the removal and replacement, I kind of think the fault probably was in the o-rings. But, I am curious and will try the hot water idea out just for fun.

 

[cjtroutt]

Head gasket or liner oring & maybe Crack in Cly bore passage.
oil cooler went bad it will be oil in radiator & allot of it.

 

[dabtl]

Head gasket or liner oring & maybe Crack in Cly bore passage.
oil cooler went bad it will be oil in radiator & allot of it.

When I drained the antifreeze there was no sign of oil in it. Guess I am lucky?

 

[Maverick1701]

When I drained the antifreeze there was no sign of oil in it. Guess I am lucky?

ihope im as lucky...im going to change mine tomorrow...pics to come