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1998 GMC 1500 Pickup Question: Oil in the overflow tank?

 

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wrenched, 5.7L V8, Twin Falls, ID, January 09, 2011, 11:55
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 Technician

I bought a 98 pickup and it has been sitting for about 6 mos. I checked all the fluids and it had about a 1/2" of oil floating in the overflow cooland tank. The motor runs great and the radiator water doesn't look bad. Where could this have come from? I cleaned out the tank and hope that it won't do it again. Any other ideas? Thanks-K

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  • Answer #1

    January 09, 2011, 13:30
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     Master

    GM vehicles have had problems with Dexcool coolant eating through their intake manifold gaskets and then leaking oil in to their coolant. If it persists, I would think about replacing the intake manifold gasket and possibly the whole manifold, if it is pitted, ASAP.

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    wrenched, January 09, 2011, 15:06
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     Technician

    This pickup had green coolant in it. Did the 5.7 have this problem too? I thought it was a V6 problem. Thanks-K

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