I have developed a coolant leak in the return hose where it ties into radiator. I noticed that there was oil in the coolant. At 105k I had coolant flushed and and oil changed. At 110K I had oil changed again. At 110.5k i noticed the coolant leak. There is no water in oil. Oil still looks fresh. The oil in the coolant looks clear, assuming because there was an oil change recently. The oil level is not low either. Could be subjective because I don’t know where exactly 13qts landed on dipstick. It’s not a lot of oil but it’s still present assuming that’s what’s been causing the coolant system leaks in hoses. This will be second leak I fixed. Truck temps are normal. Truck is 2017 4wd 6.7l all stock no mods. I have maintained this truck in terms of fluids and filter and don’t drive it like a raped ape. From what I read it could be oil cooler leak. I have had the nagging oil pan seep that started 50k but has just been an occasional drip with no significant oil loss. Just wondering how can an oil cooler leak oil into coolant without returning coolant into the oil? Forgot to add all temps run normal.

 

After the coolant flush did you go back with the Motorcraft orange, WSS-M97B44-D, or did you go with a green universal? Also was there any chemicals used during the flushing process that might not have been compatible with the Motorcraft orange? I've heard its very sensitive and doesn't play nice with other coolants or flushes.

 

went back with Motorcraft Orange. Only water was used for flush.

 

Blown head gasket or oil cooler

 

Oil cooler my guess

 

Oil pressure is higher than coolant pressure.

 

Until you turn off the engine, then the reverse is true until the coolant reaches ambient engine temperature.