Reply To: Coolant fun.

[BernieParticipant]

My immediate thought is that the bubbles are the result of a combustion gas transfer from at least one cylinder to the cooling water labyrinth.  Possibly a gasket failure or a crack somewhere in the hardware.  Either option would not necessarily result in oil/water contamination.

But, if you are not overheating, that seems unlikely.  However, to be sure, a compression test is likely to show any cylinder leak and there are testing kits available that will detect combustion gas traces in the coolant.

If  the problem persists and you are still concerned, I would suggest draining the system, flushing and filling with fresh water to see if bubbles persist.  But I don’t know what else to suggest if they do.

Sorry, I can’t be more helpful.
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