Cat c15 oil in water help

Oil cooler is the usual culprit.

 

Might be the transmission oil cooler too if you have the liquid cooled transmission. Had that happen to me.

 

that my be it but usually if it's bad you will get coolant in trans because it has more pressure on the coolant side 7-13psi depending on cap probally oil cooler more pressure on oil side say 40-60psi oil pressure

 

That would be my guess. The cheapest place to start as well. ~$5-700. Something you should be able to do yourself. Not to awful bad, assuming you have room in the engine compartment.

 

If it was a trany cooler you will smell it in the radiator. Oil in the water could be from the oil cooler,water pump,liner orings. Are you sure it engine oil? You can remove the oil cooler then plate both ends and pressure up with shop air and drop the oil cooler in a bucket of water.Make sure you go both ways when pressure checking oil cooler reverse the plates.If no leaks then remove oil pan,pressure up cooling system and look from bottom of block this way you can see if its liners,water pump. ,head gasket grommets.

 

i had that prob on a 3406e it started small then it flooded the water system, burst a hose and am sure to hell that it was the cause to the cracked head a few days later, water temp went to 240f, the water system was clogged