coolant in oil


Old 06-01-09, 02:23 PM
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coolant in oil

98 GMC pickup with a 5.7 there is coolant in oil, i belive the intake gasket is bad. I have it apart it the plastic type gasket but in ruff shape. Am I correct in assuming this is my problem and not head gaskets? No smoke came out of exhaust.
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Old 06-01-09, 07:09 PM
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Sounds like a blown head gasket. Did you do a compression test before taking it apart? The cylinders should be within 10% of each other. Is your intake water jacketed? Do you have coolant going through it? Oil / coolant is likely the head gasket.
Old 06-01-09, 07:57 PM
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9 times out of 10, it's just the intake gaskets. When they fail, it lets the coolant poor from the passage directly into the lifter valley, into the oil. When the head gasket goes, you will smell it burning in the exhaust, and the engine will run rough at times.
The new intake gaskets will be metal with rubber seals to seal the intake and coolant ports. GM revised them because they were known to fail. I recommend using GM gaskets and sealer.
Old 06-02-09, 02:26 AM
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Square Head cant do compression test already have apart
Old 06-02-09, 06:44 AM
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Originally Posted by Mr. Dummas View Post
, and the engine will run rough at times.
Oddly enough, to go against common wisdom, I periodically start up my now garage-stored 91 Spirit that obviously has a major coolant loss into a cylinder from somewhere to the point it filled the #1 cylinder up with coolant like a fish bowl, and vapors would pour out the radiator and overflow caps -so I drained the coolant out of the radiator and the cylinder, and disconnected the water pump belt so I could run the engine -and oddly it purrs like a kitten!! Even smoother than the '90 I am now driving! Figure THAT one once.

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