Oil in radiator

Usually once with soap and twice with water

 

Didn't know they changed the formula good to know

 

Had the same problem about a year ago. Turned out to have a pin hole in the cylinder liner. $15000 later new overhaul and everything works great.

Good luck with yours, hope it is not this.

 

Amen!

That use to be a big major problem for Cumming engines if you did not change out the water filter quite often, electrolytes would & can cause pin holes in the cylinder sleeves. And when it happens you get oil in your radiator & there's only one way to fix it, an in-frame.

 

When the engine is hot, you can pull off a head, look down in the cylinder, & see the pin holes.

I've seen it done on a 400 Cummings that I drove that was doing this.

 

Its easier to drop the pan, and pressurize the cooling system. Rules out all doubt, whether its a pinhole, liner oring, head gasket, oil cooler ETC.

 

Sounds like it could it be left over oil in the cooling system or a leak.
Ask yourself, how much oil? Is the oil level low? Are you loosing oil?
Drop the oil pan and put pressure to the cooling system, your mechanic should know how to do this. Also check to see if its fuel.