99 malibu this one has me stumped

I attempted to find something on this in the forum already but nothing quite fit the description of what I got going on.

I have a 99 chevy malibu that was running like it had a real bad miss in the engine. It was due for a tune up and oil change so I went to work on that. When I pulled the air intake tube off ( the big one coming from the filter ) I noticed alot of oil in the end closest to the engine. I completely removed this tube and let the oil drain out of it, yes there was that much.

I went back and replaced the plugs which were worn but didnt show any signs of excessive oil burn on them. After reassembly, the problem is even worse. The car will not stay running without keeping a foot on the gas. And now there is smoke pouring out of the exhaust.

I removed the air intake tube again and there is fresh oil in it again. As best as I can tell the oil is coming up from a tube that leads to the block. I believe that this tube equalizes the pressure in the block with the air pressure from the intake. If I am wrong please let me know. I dont have the experience that most do when it comes to the workings of internal combustion.... lol.

I have been told it may be just a clogged block and that this oil is jusst oil that cannot get back to the bottom of the engine so it is getting sucked up into the air intake. I did not even attempt the oil change yet but the dipstick is reading normal on the old oil.

I am really at a loss on this one, any help would be greatly appreciated.

Sounds like a stuck open PCV AC Type CV892C

- check yours- or better yet- replace it...

Engine won't run right or start good with all that excessive (vacuum) leak.

A crankcase ventilation system is used to consume crankcase vapors in the combustion process instead of venting them to atmosphere. Fresh air from the throttle body is supplied to the crankcase, mixed with blow by gases and then passed through a PCV valve into the intake manifold

The primary control is through the positive crankcase ventilation (PCV) valve which meters the flow at a rate depending on inlet vacuum. To maintain idle quality, the PCV valve restricts the flow when inlet vacuum is high. If abnormal operating conditions arise, the system is designed to allow excessive amounts of blow by gases to back flow through the crankcase vent into the throttle body to be consumed by normal combustion

A plugged valve may cause the following conditions:

• Rough idle

• Stalling or slow idle speed

• Oil leaks

• Sludge in engine

A leaking valve would cause:

• Rough idle

• Stalling

• High idle speed


If an engine is idling rough, check for a clogged PCV valve. Replace if required. Use the following procedure:

Remove PCV valve from intake manifold.
Shake valve and listen for the rattle of needle inside the valve.
If valve does not rattle, replace valve.
With this system, any blow-by in excess of the system capacity (from a badly worn engine, sustained heavy load, etc.) is exhausted into the intake manifold and is drawn into the engine.

Proper operation of the crankcase ventilation system is dependent upon a sealed engine. If oil sludging or dilution is noted, and the crankcase ventilation system is functioning properly, check engine for possible cause and correct to ensure that system will function as intended

thats a good idea, I will give that a shot as soon as I get up this afternoon.

I never even thought of that lil thing. must be sleep deprivation.

exactly what I was going to say. Replace the PCV valve asap. They are cheap. I believe the dealer uses an ac delco valve, I would call and check up on that. I would get OEM.

Second, If its all filled up, you might want to check the throttle body as well make sure there is nothing in there or the manifold. I'm sure there is if its as bad as you say.

I guess I could have noted that this car has the 4 cyl engine and this is what I found out about this engine.

2.4L Engine

A Positive Crankcase Ventilation (PCV) valve is not used on this engine. Blow-by gases are passed through a crankcase ventilation oil/air separator into the air cleaner outlet resonator. The oil/air separator is mounted to the engine block and allows any scavenged oil to be returned to the crankcase.
The only flow through the oil/air separator is combustion blow-by, as there is no fresh air inlet to the crankcase. The primary flow of blow-by into the separator is through a hose from the timing chain housing. The oil/air separator causes oil, which may be suspended in the blow-by gases, to be separated and drain back to the crankcase. The blow-by gases are then drawn into the air cleaner outlet resonator by normal engine vacuum and burned in the combustion process.
Periodic maintenance is not required. If the separator becomes clogged, indicated by excessive oil consumption, oil clogging in the air intake, or sudden oil leaks, inspection is suggested. FROM AUTOZONE.COM

Does this mean that the oil/air seperator is full of oil as well? I called my mother (this is actually her car) and she said that last fall she had overfilled the oil when topping it off. Could this be the cause of this issue?

Sounds like this just got alot more expensive...

Yes sir, over filling the engine can cause multiple issues. As I said before, I would clean the pipe out completely, drain the oil out... might as well do an oil change and check the throttle body and intake manifold for oil. If so, remove and clean. Put the new filter and oil on, and then turn her on, take it for a test drive and see how she performs and then check the intake pipe again. Hopefully the oil seperator is straight. So after running it for a bit you may get a little left overs... clean it out and drive it again.

With how old the car is, I would suggest removing the throttle body and cleaning the carbon out anyways. lol Its more of a preventive maitenence procedure. But in this situation, consider it extra precaution.