Oil in plenum 3100

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Guest

Oil in plenum 3100

Postby Guest » Sat Mar 01, 2003 3:45 pm

Ok so I had my plenum off about 7 months ago & cleaned everything spotless including intakemanifold. I just got a throttlebody the otherday & ported it alittlle. When I took off the old throttlebody there was quite abit of oil in the plenum??? I was wondering if there is a fix for it or what should I look at to replace things (pvc) ?? any ideas would be great Thanks in advance.   94  3100



Guest

Oil in plenum 3100

Postby Guest » Sat Mar 01, 2003 6:49 pm

pvc? as in the sewer pipes in the basement.






Guest

Oil in plenum 3100

Postby Guest » Sat Mar 01, 2003 6:51 pm

my bad i meant pcv ya know the one in the top of the valvecovers?



Guest

Oil in plenum 3100

Postby Guest » Sat Mar 01, 2003 6:54 pm

Yeah, I know, but just making sure you do:)  Change it, but chances are it won't stop it, sound like blow by the rings. You may want to take Chris's suggestion and get some GM topend cleaner, it might halp loosen up the rings and get a better seal.



Guest

Oil in plenum 3100

Postby Guest » Sat Mar 01, 2003 7:00 pm

Ok maybe I should ask this. If I take the tube that runs from the pcv to the top of the plenum & then to the rear valve cover & block off the plenum hole will it hurt anything?? I'm guessing that the oil is coming in from there. As for oil blow by I don't think that is happening I only have 48685 for mileage YES IT"S THAT LOW. I was wondering if anyone has experienced this before & if so what did they do to correct it?



Guest

Oil in plenum 3100

Postby Guest » Sun Mar 02, 2003 3:27 pm

If oil consumption is normal, & there are no other snags with your car, then do NOTHING. Oil in the plenum is normal. The PCV system puts oil in the plenum and during hard acceleration can put oil in the intake duct downstream of the air filter. During hard acceleration especially there is always going to be some "blowby".



Guest

Oil in plenum 3100

Postby Guest » Sun Mar 02, 2003 8:01 pm

Thanks for the info I wasn't sure if this was normal or not. :D  glad to hear it normal I thought I had big problems.



Guest

Oil in plenum 3100

Postby Guest » Sun Mar 02, 2003 8:03 pm

The mileage means nothing.....All it takes is one overheat to make the piston rings to lose their tensile strength, and become weak. :;):






Guest

Oil in plenum 3100

Postby Guest » Mon Mar 03, 2003 1:41 am

Let's not get carried away here. Keep it "simple". Why the assumption that the original post involved an overheated engine? In earlier posts I have given an explanation of why oil can be (and is) found in the intake/throttle body etc. I didn't dream it up. This info comes from the GM Shop Manual section 6E3-C13 which describes the operation of the PCV system. I also own (from new) a '92 GT 3.1 with 95000 miles on it, which still uses basically zero oil, that from new has always exhibited oil in the intake right from the intake duct through. It seems to have become less obvious after the porting/polishing of the intake plenum/manifold. And I don't buy the loss of piston ring tension. Most of these cars in fact will survive "routine" overheating. Even an "overheated" engine is not going to cause loss of tension of the rings. The difference between the "normal" operating temp of these engines and an "overheated" condition as "seen" or felt by the piston rings doesn't amount to a hill of beans. These are iron/steel low tension rings that are not going to loose their tension (or temper) in this way. The piston and rings are also to a large degree cooled by the oil. The danger is with an engine that was run overheated for an extended time and  where the oil temperature goes up to a point where the oil looses its ability to lubricate and cool, which can cause ring to cylinder contact and therefore scoring/pickup of the cylinder walls and piston rings (now you've got your excessive blowby and oil consumption) and possible bearing damage and worse. And we all know about the warpage issue in relation to overheated engines and aluminum heads.



Guest

Oil in plenum 3100

Postby Guest » Mon Mar 03, 2003 3:26 pm

^^ simple :)



Guest

Oil in plenum 3100

Postby Guest » Mon Mar 03, 2003 3:30 pm

Simple kinda of but well explained. Many Thanks for everyone's opinions & or advice.




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