Coolant in oil | Ford Explorer Forums - Serious Explorations

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New Member
May 31, 2015
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City, State
Slidell, Louisiana
Year, Model & Trim Level
2004 Explorer
I have 2004 4.0 SOHC. I am getting coolant in the oil. I had the head gaskets changed. Has good compression, did a cylinder leak down test which was good and I am still losing coolant with some milky substance on oil cap.

My question is: Has anyone heard of bad engine oil cooler?

p.s. Had good compression and cylinder leak down test before head gasket change.

The oil filter adapter also has coolant going thru it. If the gasket to block fails, you'll get what you have. Believe it's fairly common on the 4.0. There are threads here about it.

Not sure about the 4.0 having a water to oil cooler but I am getting rid of mine on a 98 5.0 before it fails.

Relocating oil filter and adding a air to oil cooler soon.