Bad o-rings in the oil cooler can put some oil in the coolant or, less likely, coolant in the oil.
Over the past year, I had been losing coolant, but I could not find where it was going. I looked everywhere, even with a flashlight. No joy.
Finally, it seemed to me I "might" see a bit of moisture near the oil filter on the engine block, meaning perhaps the oil cooler is leaking from the gasket on the engine there. So, I got a new gasket and o-rings, pulled the cooler, and found my 17-year-old gasket and o-rings looked perfect! I installed the new gasket and o-rings. No improvement, still losing coolant.
Losing patience too, I finally put some Bars in my coolant (a quality stop-leak for radiators), and it scared my water pump into finally fessing up. It began pi$$ing coolant out its weep hole within a week.
A new water pump installed, and my coolant stays where it should.
Last edited by Airstreamer67; 06-10-2013 at 01:21 PM.