Oil in the Intake Plenum
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Oil in the Intake Plenum
I was removing my Super Ram plenum to replace the EGR temperature sensor. When I removed the lid I found oil in the plenum. The engine has been using more more oil than normal. I also found a vacuum leak where the PCV hose connects to the intake manifold. Any possibility the two are related or should I be looking elsewhere?
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
Where is the leak?
In the grommet where the PCV valve goes in or from the hose?
Replace either that is leaking, your PCV should be fine, just shake it and if you hear a rattle, it is good.
Also, I think ac delco parts are overrated.
In the grommet where the PCV valve goes in or from the hose?
Replace either that is leaking, your PCV should be fine, just shake it and if you hear a rattle, it is good.
Also, I think ac delco parts are overrated.
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
I have always had oil in the plenum of my SuperRam. I had some when I used to run a pcv valve and still do even though I no longer run a pcv. These manifolds have a great deal of reversion and seem to suck any oil up the runners into the plenum. My motor does not use oil, but there is always a thin film of oil in the plenum. Your excessive oil use may be related to your pcv valve and leak but some oil I think is normal.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Thanks Surfer. The leak was the hose that connected to a barbed nipple on the manifold. The hose had swelled (wrong heat rating) and was leaking pretty bad. The valve is fine.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
I do have the hose from the throttle body supplying air to the valve cover. The hose is clean and dry, no oil. The oil has to be coming up the runners.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
I have an extra catch can ...for sale 
Melting Slicks
Joined: Dec 2009
Posts: 2,232
Likes: 285
Hey, cumbercr are the heads you running got screw in studs for the rockers? You might want to reseal them, I have had alot of intakes off on 2 piece manifolds, not just GMs, I find alittle oil in most of them. Check your intake bolts too.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
The rocker studs on the intake valves are blind holes. I pulled all the intake studs today just to make sure.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
why would you? if your rings and valves seal, you won't need it.
LS engines need it because the piston skirts are so short that the pistons rock at the top of the bore.
Also, they have no individual boring for individual pistons, the logic is, if you cut all the cylinders the same, and the pistons are all the same, everything should fit.......not
LS engines need it because the piston skirts are so short that the pistons rock at the top of the bore.
Also, they have no individual boring for individual pistons, the logic is, if you cut all the cylinders the same, and the pistons are all the same, everything should fit.......not
Last edited by coupeguy2001; Jan 23, 2010 at 12:31 AM.
