Water in oil.
 

Read this carefully because this is no typo. Truck is a 90 F350 Crew cab 4x4 with E4OD trans and 168000 miles. 4" lift with 35's. This is my daily driver/comutter traveling 1100 miles per week. Over the last few months I've noticed I've been losing water. Nothing real bad until last 4 weeks. Also noticed on bottom of radiator cap, foam looking stuff thats grey in color. Checked water last week and was low 2 gal and a ton of grey foam. The foam is oily to touch. looks a lot like water in oil. I pulled drain plug and NO water in oil. I do lose 2 qts of oil every 1500-2000 miles. Today check water and 2 1/2 gal low and the entire top of radiator fins inside covered in oil looking crap and cap is covered in grey oily foam. Could this be a head gasket? maybe cracked oil cooler? Something worst or something better? I have minor oil leak like most diesels, but oil in water? Almost unheard of. Should be other way around. Any help would be useful. Thanks

Have you been keeping sca additive in the coolant? could be the oil cooler too. the oil is at a higher pressure than the coolant and can move into the coolant at the gaskets. you need to do a coolant system pressure check. and have a oil sample tested for coolant. head gasket can put soot and fuel into the coolant but there are no oil pressure in the heads to leak into the coolant. check for this befor you pull the heads. rebuilding the oil cooler is cheeper than pulling the heads. and finding out the hard way. cavitation pin holes in the cylinder are harder to find but dont freek out until you check the easy things first. Good luck :pca1:

Sounds like he O rings on the oil cooler are bad if there is oil in the radiator.

Ok that explains the oil in water. I've got the gaskets and O-rings and I'm going to start this today, but can anyone explain where the water is going? I drove 180 miles and lost about 1 gal of water on thrusday. Friday I drove maybe 50 miles and now missing about 1/2 gal. racer30 asked about "sca coolant additive", what the hell is that, and where do I get it and what is the purpose of it? I've been running a 50/50 mix.

If I am not mistaken..... When the oil gets in the coolant through the oil cooler, coolant also gets into the oil. Since viscosity of coolant is different than oil, the coolant just burns up when it enters the engine.

That just sounds PREFECT!

Thanks. Glad I could help. Check out this post for the oil cooler reseal. https://www.dieselbombers.com/ford-8...er-reseal.html

Ya I saw that. Thats what I'm going by on this repair. Thanks for the help. Will give results when I finish cleaning out the radiator.

dawn dish soap and water. run it 3 or 4 times with the soap in it. will pull the oil out of the cooling system.

Cavitation is the formation of micro bubbles in the coolant, that pop and reform over and over in the coolant against the upper cylinder wall. this action removes verry small amounts of cylinder wall until it drills a hole in the cylinder, then all hell breaks loose and the next thing you know your piston is broken valves are bent and your machinest is looking at you with doller signs in his eyes.