Pontiac Repair: Suction in the crankcase, intake manifold gasket, pontiac grand prix

Question
QUESTION: I have a 2000 Pontiac Grand Prix with the 3.8 NA. I have already replaced the upper and lower intake gaskets and I still have a problem with suction from the crankcase into the intake. Or at least the Oil fill cap is being sucked onto the valve cover, i was wondering what else causes this problem??

I have also replaced the PCV valve.

ANSWER: Hi Alex:

well it's one of 2 things. either when you replaced the lower intake manifold gasket you didn't tight the gasket down properly or when you changed the pcv valve or possablyu replaced the upper manifold that you forgot to put the o-ring in under the pcv valve. take the cover off the pcv va;ve and take out the valve ther should be an o-ring seal between the manifold and the valve. If not that's your issue. Good luck :)


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

QUESTION: So I heard that a small vacuum in the crankcase is normal, but I do not know if that is true, could you help clarify???

Answer
Yes a VERY small amount is normal due to the vacuum clow though the PCV valve. But if it's strong enough that it's suniking in the valve covers then you have to look where I told you in the previous post. I didn't califiy about the bols enough. The front bolts on the manifold uner the upper plenium are the ones that need to me looked at to see if they are tight.