Oily intake manifold...?

[35Remmy]

OK guys...I've posted a long time about my pinging problem...have done EVERYTHING...lower intake manifold gaskets, seafoam, cleaned MAF, etc etc....

Now my 4.0 OHV is starting to ping on premium like everyone said it eventually would because of excess carbon buildup.

I took off my throttle body and the inside of the upper intake is all oily (air filter is clean).

The inside of the upper intake should be relatively dry, right? I did my upper intake manifold gaskets about 5 months ago (Fel-Pro 2 piece that I had a HELL of a time lining up). I'm thinking I did the job wrong. (the Motorcraft 1-piece gasket is MUCH easier and fool-proof) Ingesting oil into the cylinders would ultimately cause PING!!! What do u think?

 

[35Remmy]

Oh, by the way, I ran a paper towel through the manifold and the oil looks and smells like fresh oil, not residual after 95,000 miles (I cleaned out the manifold when I did the gaskets) I could squeeze oil out of the paper towel where it contacted the bottom of the manifold where most of it collected. Oil seemed thinned out.

 

[Four0Sport]

head gasket? some watery oil could be making its way up through the bottom plenum where it bolts to the head. just an idea. the plenum i cleaned and painted came off a motor with a blow lower plenum gasket and a busted head gasket and wasnt as bad as what youre describing but deffinetly had oil in it. took forever to clean out, did you know a toilet brush fits perfect through the hole where the TB is mounted? yeah it works.

 

[Willard]

There's always going to be some oil in your intake due to the PCV system. I couldn't say if you have a problem or not though without seeing it myself.

I guess it's worth mentioning that when I had my intake off the first time, it was pretty gross with all the oil and carbon deposits in it. I cleaned it out good, and when I've taken it off each time afterward it was already starting to build up again.

 

[Four0Sport]

its one thing to have oil residue and carbon in your intake.. but from what hes tellng us, something is leaking and allowing motor oil to gush into the intake.

 

[Willard]

Wait a second....you said you just did the UPPER intake gaskets? If that's the case, then the lower ones might be your problem.

Edit: Nevermind, re-read the first post, looks like you did the lowers too. In that case I'm not sure, I'd think oil would have a hard time going backwards through your intake all the way back up to the TB.

 

[35Remmy]

Yeah, I just did the lower intake manifold gaskets...I can't see how it would be normal for "fresh" oil (enough to soak the paper towel in spots) to make its way into the upper intake manifold like that.

I was also wondering myself if a blown head gasket could do this.

The Fel-Pro 2-piece gaskets are a PITA!!! There's nothing to hold them in place as you set the lower intake manifold on top of them. I scribed the head, the gaskets and the lower manifold as best I could to line them up.

The FORD gasket is one piece and you can't screw it up!!!

 

[Four0Sport]

did you use any silicone or tack and seal to hold the gaskets in place while you torgued the plenum down?

 

[35Remmy]

No, I didn't use anything to hold the seals in place.

Another thing I didn't like about them is there's an "empty", gasketless spot in the back of the block (about 2 1/2") that requires you to use RTV where there is no gasket because of this 2 piece design....I didn't like doing that at all and just viewed it as the 1st spot that would start to leak.

Fel-Pro says they used a 2-piece design because the 1-piece design can hold the lower intake up off of the block causing leaks. I don't buy it. If everything is torqued down correctly there shouldn't be an issue.

 

[Four0Sport]

did you use rtv on the end pieces to seal the gaps where there is no gasket? that is not uncommon for companies to make 2 piece gaskets like that and use rtv.. people do it everyday and it works. i hope you didnt skip over this step bc you thought it would leak with rtv. cause it leaks w/out it.

 

[aldive]

I was also wondering myself if a blown head gasket could do this.

Have you performed a compression test?

 

[35Remmy]

4.0...yes, that is exactly what I had to do...yes, I used RTV on the ends.

Al...yes, compression tests (dry) out good...all around 150.

 

[Four0Sport]

and the pcv system is clear and good?

 

[35Remmy]

4.0...yes, new PCV valve, hoses are good and tight.

 

[Willard]

Is there any way you could show us pictures of what you are talking about? At least that way I could compare it to what mine looked like and go from there.

Edit: Which truck is this in? I ask because if it's the 88 and it also has an auto tranny you could have vacuum modulator problems getting tranny fluid sucked into the motor.

 

[mrboyle]

How many miles on the engine? It is common to see oil in the intake plenumn. Like Jesse mentioned, its from the PVC. The more miles the engine has the more chance of oil entering the intake due to blow by. Even a fresh engine will have a slight amount of oil that is pulled into the intake by the PVC. Without actually being there to diagnose it, I can't tell you exactly what is wrong, but I think you are over reacting to the problem. If you have already run cleaners, replaced gaskets, etc... chasing the problem, with no success, it sounds like you are not actually addressing the actual problem. Detonation/pre ignition (or ping) is more commonly caused by a lean air/fuel ration than it is by carbon buildup (unless your rig has a real bad blow by). I know you are trying to fix the problem yourself, but there comes a time when you have to admit you don't have the proper tools to diagnose the problem. When that time comes you are time and money ahead by taking it to a reputible repair shop and having it diagnosed. You don't have to have them do the actual repair if you really want to save a few bucks, but let them diagnose the problem.

 

[35Remmy]

The motor is the '99 OHV in my Ranger...94,000 miles.

Devil...I'd post a pick but I already ran paper towels through the manifold to clean it, heh.

Boyle...I actually DID bring it to the shop and the mechanic told me he couldn't find anything wrong, heh. I don't use that shop anymore by the way for many reasons.

I was recommended to another shop that is supposedly a bunch of Ford nuts that know a ton about our vehicles, so that's where it looks like I'm headed.

 

[gijoecam]

Oil in the intake is quite common, especially on high-mileage engines. More mileage ==> more blowby ==> more combustion gasses moving through the PCV system ==> more oily mist carried into the intake manifold. It's common and normal. Only a complete engine rebuild *might* stop the oil from entering the intake.

The only other solution is to vent the oily fumes from the PCV system to the atmosphere, but that's considered tampering with emissions components and illegal in all 50 states.

 

[Four0Sport]

is there a way to add a oil seperator or a catch can inline with the pcv system, like between it and the intake? would that help any?

 

[gijoecam]

Several people have added them... I'm not personally a fan myself though... Aldive's got one for sure.