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what causes coolant in engine oil?

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Old 02-09-2011, 11:02 AM
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Default what causes coolant in engine oil?

I've noticed a lot of condensation and sludge build up under the oil fill cap even

after changing the oil, there is coolant entering the oil but where exactly is this

occurring? I've checked the search but couldn't come up with anything..is it the

head gasket? also the water pump occasionally leaks, any correlation?
Old 02-09-2011, 12:27 PM
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head gaskets, cracks, or other similarly bad things.
Old 02-09-2011, 12:43 PM
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^ ditto. And the condensation under the cap is normal, but excessive could be from the HG leak which is condensating on the cap.

Last edited by bayer-z28; 02-09-2011 at 06:16 PM.
Old 02-09-2011, 05:14 PM
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Head gasket's, I also agree.
Old 02-09-2011, 06:51 PM
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how much is the coolant low? any on the dipstick? if not....... just plain ol LS1 milkshake on the oil cap
Old 02-10-2011, 10:50 AM
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I also thought it would be the head gaskets, the coolant wasn't too low but the

consistency was slightly different.. There's condensation and the occasional

build up of sludge under the oil cap
Old 02-11-2011, 11:20 AM
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I noticed this on my truck, 6.0l yesterday. Have never seen it before. Kind of a yellowish greasy buildup in the cap. It was really cold last week, -28. Truck runs fine, oil on the dipstick looks fine, normal color, normal level, coolant was a litttle low, but nothing major. It has 118,xxx miles on it right now. I was kinda freeking out a little bit, especially since I have been spending so much $ on my car right now. That's all I need is to have to tear down the truck motor too.
Old 02-11-2011, 11:25 AM
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yes alil condensation on the oil cap is normal. try changing your oil seewhat it looks like. if it is milky then look towards the head/headgaskets
Old 02-13-2011, 02:24 PM
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First i would remove my radiator cap and run the car watch for bubbles in the radiator fill neck. If bubbles are present you have either a cracked block, warped head, or a bad head gasket. I had this same issue on my Z which did not turn out to be anything, when i had i found there were no bubbles in the radiator i took an oil sample to a peterbilt dealership and had it tested for contaminents with nothing abnormal showing.
Old 02-13-2011, 05:03 PM
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The same problem occured when I ran too cold a Thermostat and/or unhooked all or part of the PCV system.
Old 02-13-2011, 06:46 PM
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are you sure it is just not water vapor/oil mix under the cap? There can be quite a buildup that is easily mistakable.

For peace of mind pull the sparkplugs and have someone look at them that should tell you its a headgasket.
Old 02-13-2011, 08:03 PM
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Sounds like normal, does the car see just short drives and never gets to run long and burn the vapors out of the cap?



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