Oil in the overflow tank?
1998 GMC 1500 Pickup

Oil in the overflow tank?

(1998 GMC C1500)
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
1 answer & 1 comment
Popular Answer
on January 09, 2011
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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on January 09, 2011
This pickup had green coolant in it. Did the 5.7 have this problem too? I thought it was a V6 problem. Thanks-K
Oil Leak Diagnosis
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on January 09, 2011
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.
Sign in to reply
on January 09, 2011
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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