Kenneth Elinburg

I have a problem. I am new at LS1 AND LS2 ENGINES, I have severe crankcase vacuum it pulls air in through the rear main seal and makes it sound like a supercharger. If you put oyur hand over the oil fill tube it will try to pull your hand in. But the intake vacuum is at the right place 5 to 8 in. the engine will not idle while the oil cap is on but if you take it off it idles high.

THANKS KENNETH

sreve

iTrader: (3)

HUH? on what?

NinerSevenTango

Sounds like perhaps a nasty leak at the intake manifold.

--97T--

formulajunky

Yeah what he said. Did you have the intake off? if you did it didn't seal. Try again.

chvycmaroz28

iTrader: (1)

x2......

KILLER-LS1

iTrader: (18)

no, a leaking intake would just cause a lean condition and would have nothing to do with the crankcase except for the pcv. a bad positive crankcase ventilation (pcv) valve would cause PRESSURE in the crankcase. what you are describing is the opposite. unfortunately it is hard to tell you what exactly is wrong without looking at it. my first guess would be a problem with the heads....