Top of throttle body.

[G Winter]

ok, by right you mean pass. side. Right ?
where does the PVC hose connect ? It should connect somewhere that has manifold vacuum. The vacuum through the PVC pulls air through the crankcase. The air goes into the crankcase on the other side. This is what is hooked to your the area on the throttle body you are concerned about.
If there has been a lot of down shifting done in the past or the PCV has not been working in some way. Such as plugged or even restricted in some way, then you would build up crankcase pressure. This could cause a little oil to be forced into that hose.Extremely hard driving will cause some crankase pressure. Ideally there shouldn't be oil in the area you are talking about.A small amount of oil can appear like a lot. Even a slight mist would condense in the top of the throttle body. I would clean it up, drive it for awhile and check it again.
The way to find out for sure would be to take a compression test. Personally I don't think you have a real problem. That oil may have accumulated over the life of the car.

An afterthought , at some time during the cars life the PCV may not have been working right and the oil could have been forced there at that time. It wouldn't likely go away by itself.

Glenn

 

[Paul Higg]

Hi Glenn, thanks. Yes, I am talking about the passenger's side.

I had replaced the PCV VALVE (on the driver's side under the fuel rail cover) as a matter of course a few months ago because I want to zero time out as much as I can. I have been told by others that they have had the same exact thing. Oil on top on the TB under the rectangular cover.

We need to get this right. Correct me if I am wrong. But I ASSUME the passenger side with the foot long plastic pipe going into the valve cover has air SUCKED out of it? THEN the PCV VALVE itself, the little shiny part with the ball bearing in it would OPEN to allow air to flow out of it? Or is it the other way around? I really have not had the time to look in the FSM for a complete description of how the system works. Anyway, the car runs fine now, no off-idle bog, I can even spin the tires which I do not really want to do.

The other day Corvette Country replaced all four u-joints and a right manifold. It had two HUGE cracks in it. So big you could see daylight. That's where all the racket was coming from. Now it purrs, no racket, and the cruise holds like a rock. Personally I am quite pleased with the work I have done.

Paul

 

[G Winter]

I don't have an Lt but the system should be the same as on an L98. There is vacuum through the PVC to the crankcase, pulling air out. The air comes from under the plate which is open to the air cleaner side of the throttle body.It passes through the crankcase to the PVC,them to the intake to burn the crankcase gases.

Glenn

 

[Paul Higg]

So, was I correct in the route of air travel? Does the air travel INTO the TB from the passenger side then into the plenum?

 

[G Winter]

It travels from the engine to the PVC not from the PVC to the engine.

Glenn

 

[Paul Higg]

Glenn, I am really sorry about this but I still do not understand. The tube on the TB directly next to the throttle position sensor. Does it suck or blow on the PASSENGER side? What does the little PCV VALVE do on the DRIVER'S side? Does it SUCK or BLOW?

I am having difficulty typing and other problems and I saw my doctor yesterday and I may be having pre-Alzheimer's symptoms as it runs in BOTH sides of my family and I am 49.

 

[G Winter]

ok. On my L98 the PVC is in the valve cover on the drivers side, the hose goes to the intake manifold. On the passenger side the hose goes from the valve cover to the fitting on the throttle body just to the rear and slightly above the throttle possistion sensor . The air flows from the throttle body to the valve cover , through the engine out through the PCV and to the intake. The air does NOT flow from the valve cover on the passenger side to the top of the throttle body.
Hope I have made it clear to you. My communication skills leave a lot to be desired.

Glenn

 

[Paul Higg]

Now THAT clears it up Glenn, thanks. SO, if there is oil as I have seen as well as Junk and others, what kind of problem does that indicate? Some sort of blowback from the crankcase? Does this mean I will need an engine overhaul? It has 92,000 on the clock.

Thanks, Paul

You communication skills are fine, it is just that I could not understand how it worked.

 

[gmjunkie]

It's Not broke don't fix it!! You probly have already fixed it!! There are allot of things that can cause a little oil up there, Stuck PCV valve,Dirty Air filter,Mis-firing!! You have it running Good Now with new TPS,PCV valve and all the cracked and unhooked hoses fixed,wipe it out and don't worry about it!! Go Ride that Ride with a SMILE!!!

 

[JimBobC4]

Now THAT clears it up Glenn, thanks. SO, if there is oil as I have seen as well as Junk and others, what kind of problem does that indicate? Some sort of blowback from the crankcase? Does this mean I will need an engine overhaul? It has 92,000 on the clock.

Thanks, Paul

You communication skills are fine, it is just that I could not understand how it worked.

Does your car meet emissions ? If so, forget about it ! Your engine is reasonably healthy. I would just clean out the oil, and drive it till wheels fell off.

That oil could have been in there from years ago or from last week.
If it isn't oil out the PCV inlet, drive it man !

 

[Paul Higg]

Junk!!! Thank you!! How are things? You know what I mean. You can PM me if you'd like. I am fixin' to go for my daily six mile walk and pray, pray , pray. I need to be with the Lord on my walks.

Paul

It's Not broke don't fix it!! You probly have already fixed it!! There are allot of things that can cause a little oil up there, Stuck PCV valve,Dirty Air filter,Mis-firing!! You have it running Good Now with new TPS,PCV valve and all the cracked and unhooked hoses fixed,wipe it out and don't worry about it!! Go Ride that Ride with a SMILE!!!

 

[Paul Higg]

Jim, thanks. You are so right. I appreciate your advice.

Paul

Does your car meet emissions ? If so, forget about it ! Your engine is reasonably healthy. I would just clean out the oil, and drive it till wheels fell off.

That oil could have been in there from years ago or from last week.
If it isn't oil out the PCV inlet, drive it man !

 

[vetteoz]

The air flows from the throttle body to the valve cover , through the engine out through the PCV and to the intake.

What I said back in post #8

 

[Paul Higg]

Thanks.

 

[Hib Halverson]

If you believe there is an oil control problem, it is possible that oil control problem relates to engine condition.

One thing you can do is run a blowby test. I think the procedure is in the FSM. Also you can run a cylinder leakage test. Either can tell much about the condition of the engine.

 

[joshwilson3]

I know this is a little old thread. But you guys with oil in the top of the throttle body. Do you have an air foil installed? I just took my throttle body apart from my 89. The PO put in an airfoil. I too had oil on top. And there was oil on the thing you pull out of the passenger valve cover, so that line has oil in it.

But, when I was taking the airfoil off. I noticed there was this puck piece that goes in from the top so that you can bolt the airfoil up to it. With that puck in place, you are blocking 3/4 of the airflow going to the passenger side valve.

So, I'm wondering if that could be causing a problem? I just don't think it is a good idea to be blocking airflow for the PVC system. So, maybe that could explain why some have an oil problem with the line going to the throttle body and to the passenger valve cover.

Then you also have the airfoil sitting in front of the passages along the middle of the throttle body. So, I'm sure that too is somewhat impeading airflow.

http://content.mamotorworks.com/pdf/609091.pdf

 

[joshwilson3]

Oh, and you may want to clean your IAT. I don't know if it matters, but with an oil coating inside the plenum, I'm sure dried up oil residue on the IAT wouldn't help it. I pulled mine and cleaned it. It had a dried up oil coating on it.