oil in intake

[03_exploder]

Was helping my dad work on his explorer the other night and took off the old airbox and put on a cone filter, and I noticed oil in the intake tube. I noticed its coming in through the vent tube coming off the passenger side valve cover. Also the black box attached to the intake tube is that a filter for this problem? or for something different? I looked all over the motor for the pcv valve and couldnt find anything, im guessing on the back of the driver side valve cover under the intake manilfold where I couldnt see it?

Has anyone else had this problem with there explorer? and is this a normal issue with these motors? This is the first I ever worked on these motors and dont know much about them. I myself have a 98 F150 with the 4.2 and noticed there very similar but I have never had anything like this with mine.

Its a 4.0 V6

Thanks!

 

[1AJeremyD]

Welcome to the forum! This is normally caused by oil blow by. It is normally caused by a amount of the combustion inside the engine escaping past the rings on the pistion and pushing the oil into the PCV valve. Change out the PCV valve and see if that helps and also replace the air filter as soon as you can.

 

[borland]

I think this is normal. The manifold design is such that oil vapors can condense and collect in there without being sucked into the combustion chamber.

I just replaced the right valve cover gasket on my 2002 XLT 4.0L SOHC, the process also requires removing the intake manifold. So, I know what you experienced with the oil.

My truck has 125K miles, original PVC valve, and always used Mobil 1 15W-50 synthetic motor oil. I don't recall what Ford recommends for milage as for replacing the PVC valve, but you could check your owners manual for that.

 

[1AJeremyD]

As long as the oil is not on the air filter it does not pose a problem. All vehicles have oil blow by but once it reaches the point where it is soaking the air filter, then its time to start looking into compression testing your cylinders as long as your PVC valve is not stuck open.

 

[03_exploder]

Its running out of the air filter a tiny bit cause the tube angles down. But that vent tube doesnt have the pcv in it. It has a rubber hose on the valve cover and then has a 90 degree plastic fitting on the n the other end and pugs into the air intake tube. So its the oil from the valve springs and rockers thats coming up that vent. I dont understand why the pcv isnt in that line? So far I have yet to locate the pcv on this motor do you guys know where it is? I looked all over so im assuming its somewhere hard to get to.

And Thanks! Im glad I found the forum Im on one for my F150 and it def is a help when you cant figure something out or get stuck working on something.

 

[Ronin8002]

The PCV is on the driver's side valve cover. After the PCV, that line feeds right into the intake manifold.

Try replacing the PCV and see if it helps...sounds like it's stuck open allowing too much oil vapor to come through the system and allowing it to accumulate in the intake tube.

Either that or the engine is very worn.

 

[03_exploder]

Im hoping thats all it is just a quick fix. And the motor is in real good shape only 100k and runs great. Just wondering tho if the pcv is on the drivers side whats the point of the hose on the passenger side thats going to the air intake where the oil is getting in? can that just be plugged since there is a pcv on the other side for the blow by to escape?

 

[Ronin8002]

No, don't plug the hose going to the intake tube...it's an important part of the overall PCV system.

Think of the PCV system as a loop. Fresh, filtered air comes in through the the tube attached to the intake tube. It goes into the passenger side valve cover, gets circulated through the crankcase where it picks up blow-by gases and oil vapor, then it works its way up to the other valve cover where the PCV valve is. It will go through the PCV valve, through the tube attached to the intake manifold, and then all those gases and vapor get burned in the engine.

So if you plug half of the system, it won't work right.

If your PCV valve is stuck open or stuck closed this can lead to excessive oil vapors and blow by gases ending up either in your intake tube or your intake manifold. Same thing could happen if you plug one side of the PCV system.

Fortunately the part is very cheap so it wouldn't hurt to buy one to see if it clears up the issue.

Here's a diagram that shows how it is supposed to work:

 

[03_exploder]

Ok i figured it be ok since it had the valve on the one side. So the black box on the air intake tube is that supposed to be a filter if oil does get in there? I was wondering what that was for?

 

[Ronin8002]

You mean the box that is attached to the intake tube and sits on the side of it? If that's the black box you are referring to, it isn't a filter...it's a heimholtz resonator.

Basically it cancels out the whistle noises that the intake tube would make if it wasn't on there. For some reason the engineers at ford thought that whistle noise would bother people, so that's why the resonator is there.

 

[03_exploder]

Yea, ok I get what ya mean now. I had no clue what it was I thought maybe it was for the problem were having now. Yea I dont know why that would bother ppl. I took the stock air box off and took the cone filter and shroud I had on my F150 and put it on his explorer and its awesome just the difference it makes in acceleration alone, but thats when I seen the oil in there. Hopefully the pcv will take care of it. If not what else could be the cause? All the years I've worked on cars and going through schooling I never heard of this or ever seen it before so Im just at a loss as to what it could be.

 

[Ronin8002]

Only other cause is a lot of wear on the motor, but sounds unlikely based on the mileage.

When you check the PCV also check to see if the tube going from it to the intake manifold is blocked.

 

[03_exploder]

Ok thank you very much for the help I appreciate it. Hopefully we can go get what we need this weekend and see what happens.

 

[Ronin8002]

no prob. please post up here if it fixes the problem

 

[Ronin8002]

Also, I found this thread that should help you with replacing the PCV:

http://www.explorerforum.com/forums/showthread.php?t=258087&highlight=oil+intake+pcv

 

[03_exploder]

That is an awesome thread! Didnt realize this was an electronic pcv valve. It said if it comes disconnected it will stall the engine and have a vacuum leak. Right now it hesitates when it starts up but is fine once it starts, so im guessing if its clogged or getting clogged it could be causing that hesitation if the vacuum isnt right.

 

[03_exploder]

Well we got the new pcv valve in and when we went to get the old out it was just hanging there not plugged in which would explain the hesitation we had cause it wasnt drawing the right vacuum. After we got it in what a difference in acceleration alone with the right vacuum now and no oil in the intake! (as of tonight). Thank you for the help!

 

[Ronin8002]

glad you were able to get it fixed!

 

[03_exploder]

Me too, now I can do the work I want to on it for him. I have the old flowmaster 40 series off my F150, 9mm plug wires, and e3 plugs for it yet.

 

[Skybrody]

Forum about the pvc valve and going up into the plastic intake was the main cause of my oil leak, pvc valve not working. .... thank you to whom it may concern I'm a new member