I have my plenum and runners out right now and I noticed something weird. There is a thin film of oil covering the inside of the plenum and runners. The hose going from the passenger side valve cover to the TB also has a lil bit of oil in it, so I'm guessing this is where it's being sucked thru. Now as far as I know, this is part of the PCV system and that hose is for routing clean air to the inside of the block. The air then circulates inside collecting the vapors and finally gets sucked out into the intake thru the driver's side hose and PCV valve. If this is how it works, why is this hose mounted to the TB without some kind of valve to prevent oil from being sucked inside? Do I have to buy a breather to prevent this? I mean this is how it came from the factory so maybe this is normal. I can't take a pic of it but I hope I described this well enough. Thanks.

 

There is vacuum inside the plenum and intake, and that works to suck oil vapor from both valve covers. It's perfectly normal.

 

Ok thanks. I just wasn't sure the right side hose was also supposed to suck vapors. I thought it was only to introduce fresh air into the crankcase.

 

Yes, it IS supposed to supply fresh air to the PCV system. The other side of the PCV system is supposed to scavenge oil vapor and combustion byproducts from the crankcase.

If the PCV valve or connecting hose are not intact, clear, and operating correctly, you can build crankcase pressure that with flow back through the crankcase vent tube to the throttle body and coat the plenum/runners with oil. Also, if you have worn rings, damaged pistons, or any other wear causing excessive blowby, the same things can occur regardless of the PCV system. Start by checking the PCV valve (or replacing it with an AC/Delco one ONLY) and make sure the PCV valve hose is clean, in good condition, and connected properly.

 

Yeah there is a very thin film of oil. A lil more in the plenum. Nothing major, but I didn't think it was normal. I will get a new valve tomorrow at the dealer and go ahead and spray some cleaner inside the plenum so in a few days hopefully I'll be able to tell if it worked. As far as internal wear, it's probably not the problem. At least I hope not. The heads were replaced about a year ago and while the motor was apart the dude said the block is still in pretty good shape, although it's not the one that came with the car. At idle it does shake slightly (could be PCV or just normal shake) but other than that, the motor feels strong. I have no leaks anywhere, it doesn't smoke and I also did a vacuum test a while back and it didn't show anything abnormal (I am constantly checking up on this car as you can probably tell ).