1996 Buick Roadmaster Oil in Water

1996 BUICK ROADMASTER
85,000 MILES • V8 • 2WD • AUTOMATIC
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BSTILLW
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Hi: I have oil in the radiator overflow tank on this car. Did oil change and checked oil first and was not showing on dipstick. Checked farther and found that overflow tank had lots of thick oil residue in it. The transmisssion fluid level is OK. There is not radiator cap on these cars so can't look directly in radiator but that's where the overflow comes from. Also have 96 Impala which uses the cooler in one side of the radiator for an oil cooler but Bucik does not have an oil cooler. It uses both sides of the radiator in series as transmission cooler. Found one web site that suggested head gasket was issue, but don't think that there is pressurized oil in the head. Seems to leave the engine block itself. Figure it has to be oil under pressure to get past pressure in the cooling system!? Any ideas? Also need to know how to prove diagnosis if there are ideas.

Thanks!
Nov 5, 2008 at 3:33 PM
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DOCFIXIT
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Try removing recovery tank. Clean it then flush engine. Was this stuff brown gook stuck to sides and bottom of tank? if so long over due for coolant flush
Nov 6, 2008 at 9:30 AM
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BSTILLW
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Actually it is black and there is a good bit of it in the recovery tank. I put in Barr's and a tube of the graphite powder about 2 months ago. But black stuff seems to coincide with loss of engine oil!? Probably should pull heads and replace head and manifold gaskets as it was fouling the #8 plug with whitish deposits before the stop leak. I thought it was likely that it was antifreeze getting into the combustion chamber. Haven't had a problem with the fouling since the stopleak but then this showed up.
Nov 6, 2008 at 2:01 PM
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DOCFIXIT
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It is unusal to get oil in water it's usually the other way. But if gasket failed near oil paggage the pressur could push oil into coolant.
Nov 6, 2008 at 2:11 PM
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BSTILLW
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Only thing I can't explain with head gasket is that I did not think there was a pressurized oil passage between the block and heads or between the block and intake manifold. Is there one? If not, head & intake gaskets probably won't solve it.
Nov 6, 2008 at 2:26 PM