Insane crankcase vacuum

crashcrash
Tue, 16 Nov 2010 20:11:21 +0000
Maintenance/Repairs

HELP! I have a 2001 GMC Express van 3500 series 8.1 litre vortec. We need this van. We have a disabled son and work with youth ministries.

Some time ago (14 months) while the vehicle was running I noticed a slight vacuum when I removed the oil filler cap. I was told at the time this crank case vacuum was part of the engine design for these vehicles. Several days ago my van began to show an engine fault light and was idling high. At that time I once again removed the oil filler cap but this time the vacuum was tremendous! It makes my Hoover central vac look like a play toy! I have no idea if this crank case vacuum increase was slow or instantaneous. I also do not know if it is related to my high idle. My first concern is this crank case vacuum, I can have the faults diagnosed. I have been told by the dealer my engine has no P.C.V. valve. What are your thoughts? What is causing this insane crank case vacuum?

P.S. my van is not a Savana, the drop downs made me choose that

21 posts - 12 participants