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?

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.


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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.


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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

Re: Oil in Plenum
 

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.