Oil in Plenum - ZR-1 Net Registry Forums

rosseich · 01-07-2024

I have a '95 with 9,500 miles and just pulled the plenum. There was oil residue in the runners and oil also drained from the PCV port in the plenum. All the hoses are original, and the PCV hoses were oil soaked. Any ideas?

Jagdpanzer · 01-07-2024

Some oil in the plenum is not unusual for a normal running LT5 engine with original PCV system. You might check the injector housing gaskets for any seepage. Otherwise provided oil consumption is not a concern wouldn't worry about it.

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HAWAIIZR-1 · 01-07-2024

These cars will always have some oil residue in the PCV system. This car needs to be driven for sure and the worst thing is sitting. Is your PCV hose that houses the valves soft like a noodle and collapsed? They get old and soft so it wouldn?t hurt to replace it and the PCV valves. If trying to NCRS then keep all your old parts. I?m removing the PCV system with a catch can that has an integrated PCV system. I don?t like the design on the LT5.

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tccrab · 01-07-2024

Jerrys Gaskets has all the PVC hoses in stock:
https://www.jerrysgaskets.com/pcv-system-emissions/

A little oil is ok, a lot would be indication that something isn't quite right.

Crabs

AndrewL · 01-15-2024

All of the above, but also check the coalescing filters are still in place in both cam covers. The filters help manage oil vapor from the cam covers that is vented into the throttle body. When I got my car and checked them, one side didn't even have a filter at all.

01-07-2024	#1
rosseich Join Date: Dec 2023 Location: Minneapolis Posts: 14	Oil in Plenum I have a '95 with 9,500 miles and just pulled the plenum. There was oil residue in the runners and oil also drained from the PCV port in the plenum. All the hoses are original, and the PCV hoses were oil soaked. Any ideas?

01-07-2024	#2
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,644	Re: Oil in Plenum Some oil in the plenum is not unusual for a normal running LT5 engine with original PCV system. You might check the injector housing gaskets for any seepage. Otherwise provided oil consumption is not a concern wouldn't worry about it. Sent from my iPhone using ZR-1 Net Registry __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake

01-07-2024	#3
HAWAIIZR-1 Join Date: May 2010 Location: Japan Posts: 3,540	Re: Oil in Plenum These cars will always have some oil residue in the PCV system. This car needs to be driven for sure and the worst thing is sitting. Is your PCV hose that houses the valves soft like a noodle and collapsed? They get old and soft so it wouldn?t hurt to replace it and the PCV valves. If trying to NCRS then keep all your old parts. I?m removing the PCV system with a catch can that has an integrated PCV system. I don?t like the design on the LT5. Sent from my iPhone using ZR-1 Net Registry __________________ Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048

01-07-2024	#4
tccrab Join Date: Oct 2004 Location: Folsom CA Posts: 1,643	Re: Oil in Plenum Jerrys Gaskets has all the PVC hoses in stock: https://www.jerrysgaskets.com/pcv-system-emissions/ A little oil is ok, a lot would be indication that something isn't quite right. Crabs __________________ TomC '90ZR1 #792 Honorary Pirate [B]If it ain't FUN, you're doing something terribly WRONG. [/B]