Okay, I'm adding a picture to this, it might be a bit big, sorry! Oil breather tube that runs from my intake to my valve cover gets oil in it. Where it connects to my CAI there is oil stains on the pipe. Also, there is a t-connecter on the tube that goes to another vacuum line that runs off to the driver side of the car (pcv valve maybe?) Anyways, the pic included is not my engine bay, but this is what I'm looking at essentially. The blue arrows are the oil breather tube and where it connects. The red arrows are where the t-connecter is and the vacuum line and where it runs too.


My question is this: Is oil supposed to be getting in these lines? And, if not, why is there!?

The small vacuum line that heads off to the drivers side is clear where it connects to the oil breather tube and I can see that oil is in there. It's not filled with it, but its enough that the "clear" tube is the amber color of oil.

Any clues!?




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Well that tube is sucking [vacum] when the engine is running, and it is pulling oil vapors from under the valve cover. So there will always be a little bit of oily stuff in the intake.

However if it is a large amount, it can be caused by worn rings allowing excessive blowby.

I guess that your engine mileage is top secret information, but I had a krypto security clearance when I was in the service, so you can tell me.

 

whoops! 198k. She's an oldy but goody. That would make sense then if the rings were worn. A compression test can confirm that correct?

 

A small coating of oil is normal. A lot of oil means that you need a new PCV valve. Easy, cheap fix if necessary.

 

Under heavy throttle, PCV flow reverses and oil vapor is pulled from valve cover into intake rather than air from intake into valve cover (normal). Lots of WOT use would make oil in intake much worse. A poorly functioningor non-existent PCV would make this much worse. Make sure PCV valve is installed, clean and PCV to valve cover hose is open.

good luck

 

Correct me if I'm wrong, but a.) the PCV is a check valve with a ball in it to prevent flow back into the valve cover and b.) oil vapor while not intended, is commonly sent through the breather hose as well, which enters the intake manifold to be burned.

And yes I do agree that driving in the higher RPM range is going to send more oil through the intake.

 

Flow thru the PCV valve is always in the same direction, towards the intake manifold. Exception would be under boost, if you have a turbo- or super-charger.

Its the other vent line, which Benji is talking about; THAT one can reverse its flow directionunder wide-open throttle. Or, when bad rings cause enough blowby that the PCV valve cant suck it all out.

Im confused about that other line over to the left fender. Does that go to the cruise-control? If so, it shouldnt be coming from the crankcase vent.

 

All cars I've had will reverse flow into the intake (not through PCV), but from crankcase blowby pressure build-up combined w/ low manifold pressure under heavy throttle. You have to monitor crankcase pressure (pressure in valve cover) to see this effect. If there never was any reverse flow, you would neversee gunk in the IACV or black carbon buildup all over the inside of the intake manifold. It would be nice and shiny.

Good Luck

 

Well, I'm going to check out a manual to find out what that second vacuum hose is for and see what its there for. I know it runs to a little black plastic bottle type of thing about the size of a medicine container. Which is right next to another vacuum type of container and BOTH are covered by a plastic shield.

 

Well after checking the shop manual. The first one (the big one) that runs to the cai is just labeled as a breather hose. the one that t's off of that is labeled as just a vacuum hose (However, on the stock intake it has a separate barb that it connects to.) The pcv hose is separate from these two. I'll look further to see if I can find out what the vacuum hose goes to.