I've had some oil consumption issues/ plugs fouling. Leakdown tests looked ok, so I just pulled my intake off to have a look around. Things ive noticed:

1. I did not put RTV on the rocker studs - the port work on my heads cut into the stud holes and it looks like oil is getting sucked in past the threads. This is definately one source of oil

2. The intake->head gaskets were in good shape, it looks like very little oil was leaking past them, if any.

3. Light oil coating in all of the head's intake ports

4. The main intake passageway was coated in tarred-up black oil, and also had runny fresh oil all over it.

I'm at a loss as to how that much oil got into the intake, espeically with all of the gaskets in as good shape as they were. I think I would also have to have some serious reversion going on for the rocker-arm stud oil leak to have caused this. To me, that only leaves the PCV system as a suspect.

Main question is: Am i leaving out another possible oil source, or is the oil in my intake probably coming from the PCV system?

 

Its very common for the oil to be entrained in crankcase vapors that vent out of the passenger side valve cover. Take the top plate off the throttle body and look for oil buildup. Check the hose from the valve cover to the TB for oil. Both those would confirm the PCV vent line as a major contributor.

The vent line from the TB to the cover is supposed to flow fresh air into the valve cover, to be pulled through the crankcase by the PCV system vacuum. But with excessive ring blowby, or just spending a lot of time at WOT could cause the flow in the vent line to reverse, and blow the vapor into the TB - that's what it's designed to do. Check for excessive blowby. Check the baffle ni the valve cover under the vent hose connection to make sure its still there - sometimes removed to clear roller rockers.

Some people have put a small Deutch oil filter in place of the plastic elbow that plugs into the valve cover. That might help hold down the oil entrainment, if that's where its coming from.

 

I would think that it's coming from the lifter valley and the PCV. When I changed my intake I used a thin layer of black RTV around the intake ports to help the gaskets seal. Definitely put some RTV on those rocker studs though.

 

I have the filter mentioned above, problem fixed.

 

part # for the filter and where to order from?

 

I'll definately use RTV on the new intake gaskets to prevent oil in the lifter valley from getting sucked in.

As for the PCV system, the engine has about 18k miles on it, and about 2k miles ago I noticed the PCV fresh air feed and the top of the TB had lots of oil in them. I installed one of the Deustche filters Injuneer mentioned and it seems to have eliminated most of the oil getting through the fresh air feed.

But I also thought that oil could be getting in through the PCV valve itself. It seems like all of those oil-impregnated fumes could get sucked through the pcv and into the bottom of the intake (thats the where IAC passageways are right?). That wouldnt be a direct shot to the main intake passageway, but if we are talking about vapors here, maybe its a possibility.

 

Get an inline fuel filter from your local parts house that is the right size for the hose and install it in the valve cover hose, 99% of your oil will disappear.

 

So it seems the general consensus is that the PCV fresh air feed on the passenger valve cover is the main problem. Thanks for all of the suggestions.

But am I totally wrong about suspecting the PCV valve itself? Is is possible for oil to get drawn through the PCV valve and into the lower intake passages?

 

It's possible but ya wouldn't see it at the TB or the front of the intake.
When ya go WOT the air rushing by the hole in the TB(for cover vent) produces a vacuum and sucks oil in the TB from the valve cover.
The filter traps the oil and keeps it from the TB.

 

They have them at Autozone.
I don't have the p/n but its a round black plastic filter about 2 in. across and about 3/4 in tall with a hose spigot coming off it sideways. Costs 2 or 3 dollars.