major vacumme leak

[DOLZIE]

1995 bonneville
155,000 miles
engine got hydro locked, and replaced upper manifold, and lower intake gaskets. Engine now has developed a vac problem in crank case, if you remove the oil cap the engine runs poorly and will almost stall out, it has so much suction that it will is hard to remove the cap. I replaced the pcv but no difference, i removed the upper manifold and checked the lower gaskets to see if they moved, all look good, any suggestions?

[Balta]

I also have excessive vacuum in the crankcase. (96 Bonnie - 3.8, no turbo). I pull my dip stick and the air whistles it is rushing in so fast. After the engine gets hot, I get intermittant squeals and chirping sounds under the hood. These go away if I pull the dip stick to reduce the vacuum (however the engine almost stalls, as DOLSIE also mentions).

I haven't been able to find a cause - If anyone has heard of this - please let me (and DOLSIE) know!

[A92Typhoon]

I don't know whether you've found your problem yet, but there was another post on 4-5-05 that have some suggestions. Also, my father just fixed this same problem, but not exactly sure what he did. He changed intake plenum, intake manifold gaskets, EGR, and PCV and the problem went away (now there is check engine and other issues). He feels like the o-ring under the pcv valve was missing from when he changed it years ago, and that is what was causing it. I'm sure a bad pcv could cause this issue too.

[Balta]

Thanks for the tip. I had replaced the PCV last fall, but I still have the vacuum/squeal problem. I'll take another look and check for missing O-rings.