How much oil should be in the plenum?
I'm disassembling my 4.6 in my '04 Exponential, and the plenum has about 1/4 in. of oil standing in the bottom of it.
I'm getting down to the head gaskets because of suspected failure there, as evidenced by the white smoke. The throttle body was really dirty and sticky,too. Could there be a condition that causes the big vacuum lines to return a lot of oil? PCV stuck open? Or forced open by failed head gasket?

 

None at all, only air and fuel should enter into the plenum.

 

That's what I was afraid of. I'm going to research how oil could have entered the plenum.

Also, in disassembling the plenum I discovered that the gasket for the IMTV is cracked up. Anybody know where I can get it besides the dealer?

 

The intake gasket is the usual suspect.

 

Not sure how big the difference is between the 2v and 3v between '04 and '05, but I recently replaced my intake gaskets while having the intake off for fixing something else, and I had oil in the intake manifold as well. I also found oil in the spark plug well for cyl 7, so I suspect that I have a leaky valve cover gasket. Not sure how it would make its way into the manifold itself, but I'd say it has to come from the PVC in some way as there's not so many other ways it can make it in there. I'm gonna check that when I replace the valve cover gasket.

On mine there's not much oil residue on the thin PVC hose on the neck above the TB, so might suspect the thicker one on the drivers side. Not sure if the '04 has a similar setup with the PVC hoses, as I haven't seen that engine up close yet.

 

I *think* the thicker one your referring to on the driver's side is the fresh (filtered) air intake for the PCV system.

 

Well, after looking a bit more in the workshop service manual, the thinner hose going to the passenger side near the oil filler cap is the PCV "breather" hose, while the thicker one on the drivers side is the one with a PCV valve and all that, as well as a heater in the 3v engine at least. If there's oil in the intake, one suspect is the PCV valve, and I think (but not sure) that if it's stuck open it could lead oil into the intake manifold. Same if there's a vacuum leak (I had a vacuum leak) and other conditions. The PCV valve itself is an integral part of the driver side valve cover, and can't be replaced on its own and you'll have to replace the whole valve cover. If it's just dirty, it might be enough to clean it.

And that's what I'll do with mine, to make sure it works properly. The engine had misfires and lean code on bank 2 before, as well as broken knock sensors, but after fixing the knock sensors, replacing the gaskets and making sure all vacuum connections were good, as well as replacing the PCV hose and spark plugs including all rubber boots, it runs like new again, HUGE difference! And no more codes, apart from P0420, damn cat on bank 1..... lol... That cat probably went bad due to the issues I had before and I wouldn't be surprised if the oil in my intake was a result from that as well. I have to replace a leaky valve cover gasket on drivers side anyway and might as well clean the PCV valve while I'm in there.

 

Skauber,

would you mind taking some pictures of the PCV/Valve cover arrangement when you pull the valve cover?

If you do attempt to clean the valve, can you let us know what you did?

I've done a lot of searching about the PCV system on these 3V engine, and there just isn't that much information out there to be found.

I'm suspecting a PCV problem on my truck as well, but i don't want to go digging around on it without having a visual reference. That is to say, i don't want to pull the valve cover to clean the PCV only to find out that it cannot be cleaned and can only be replaced.

thanks in advance!

 

Sure, I can do that. But this project wont be until mid or late next month. I'm in the Philippines so I have to order in the parts and all before I can do it. Kinda sucks, as I have no way of just heading down to the local parts store and find any parts what so ever to my truck, even the Ford dealer has to order in parts and charges out their asses for it... lol.. Anyway, I'll update the thread when I have done the job and try to snap some pics of the inside of the valve cover and the PCV valve when doing it.

In the mean time, I do have a factory workshop manual with some diagrams in it if you want to have a look at it. It doesn't say much, basically just tells you to replace the items if there's an issue with it and simply says the PCV valve is a "non-serviceable part" and requires replacement of the valve cover if it goes bad..

 

Skauber, I did more research, but not as much as you! Thanks for sharing that.
Mine is the 2v motor, and the pcv valve is on the passenger side. the two lines are hard plastic with short soft rubber segments where they connect at the ends. The connectors twist out of the valve covers, but I haven't checked at my local O'Really?s for a new one yet. If they work fine after cleaning, then I'll try that. it'll be a little bit before I can tell if it works since I am going after the head gaskets first. good thing this is not my only vehicle!
Would it be okay to use rtv to make a new gasket for the IMTV with the plastic plenum? I don't know what problems it might cause.