Coolant and oil mixing

Tiny
ANONYMOUS
  • MEMBER
  • 2002 BMW X5
  • 3.0L
  • 6 CYL
  • TURBO
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
I replace the head gasket now when I'm putting coolant back into the expansion tank it's coming out of the oil drain port. Where else could the problem be? The leak is quite great as I can watch the coolant going down and pouring out the oil drain.
Tuesday, March 10th, 2020 AT 4:41 AM

1 Reply

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
More than likely you have a crack in the coolant passage that is allowing coolant into the oil passage or worse yet, into the cylinder. I would pull the plugs and use a borscope to look in the cylinders for coolant. If they are dry then you need to start disassembling the engine looking for cracking in the coolant passage.

The other major cause is the head gasket. The fact that you just changed it, it is either not torqued properly or the head is warped. Did you replace the gasket because the engine overheated? If so, you need to straight edge the head and block.

https://www.2carpros.com/articles/coolantantifreeze-in-the-engine-oil
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Tuesday, March 10th, 2020 AT 8:01 AM

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