Pontiac Repair: Oil Leak, silicone sealer, torx bit

Question
QUESTION: Hi, I have a 2001 Grand Prix with the 3800 Series II V6 with 155,000 miles. I noticed oil, about the size of a quarter, on the garage floor and when I changed the oil the pan was wet in places. When I put the oil in I also noticed oil on the intake manifold.. I took it to the garage and asked them to install new  valve cover gaskets.  A week later there was oil on the floor again. I went back to the garage and they said they would them again again at no charge but maybe the plastic valve covers were warped. I suggested maybe I could get one new cover to see if that was it. Just before I ordered it I was looking where the cover, head and intake meet and though, the oil would almost have to squirt from the valve cover to get onto the intake and if the intake gasket leaking there should be oil in the coolant or coolant in the oil but there is not? Is there somewhere else the oil could be coming from, before I do the valve cover again?
Thanks, Robert.

ANSWER: Ho robert:

I have never seen a regular non super charged engine valve cover warp. so I would say it not the cover gaskets. I would venture to say it's where the intake meets the heads there is a gap there and if the intake gasket was done and no silicone sealer was used in the corners that that is by it's leaking there. I have never seen a head gasket on these leak oil. your sure it's laking from up on top and running down not out the rear of the engine by the rear main seal??


---------- FOLLOW-UP ----------

QUESTION: Todd, thanks for your reply. The intake gasket has not been replaced. There are cavities on the intake where the oil is a 1/4 inch deep. The whole intake is damp with oil even in places where the intake is higher than the intake gasket. There is a bracket that goes over to the alternator and the bolt that connects the bracket to the intake has oil inside it where the torx bit goes in, and this bolt faces away from the intake gasket. Is there oil inside the black plastic upper intake cover on top ? That seems to be the only other place the oil could be coming from. Has there been any service bulletin from GM for this upper intake or anything else?
Thanks again, Robert.

Answer
No none. But the Replacment gasket from the factory is now an aluminum gasket as opposed to the plastic gaskets they had on it when it was built. other then that nothing. If this is pushing oil out past the threads on the gasket the engine may have excessive blow by or the wrong PCV valve in the upper intake manifold. When I do these reseals I put white liquid teflon thread sealer on the bolts and it stops the blow by from leaking past the threads. The upper intake manifolds are notorious for warping and leaking oil and coolant out the rear. the upper manifold is made of plastic and well you know what happent to that after thousands of heat cycles.