Working on a Detroit 60 series in a Kansas City shop taught me to check the oil cooler first

We had this truck come in with coolant in the oil, and my boss said to pull the head right away. I spent a whole day on it, only to find the head gasket was fine. The old head mechanic, Frank, walked over and said, 'Kid, on these, it's almost always the oil cooler.' He was right. I swapped the cooler in an hour and the leak stopped. Now I always start with the simple stuff, even when the symptoms look big. Anyone else have a go-to first check for a 60 series with milky oil?

2 comments

2 Comments

simon_davis1mo ago

Reminds me of a time @brian_murray saved us from chasing a phantom head gasket leak for days.

brian_murray1mo ago

Check the aftercooler core too, they can leak internally.