Oil in the intake and vacuum lines?

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theophile

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2002 V8. Been noticing the accelerator sticking at the beginning of travel lately. Took off the intake hose to find this:
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Is this normal? Is there a recommended way to clean other than throttle body cleaner and rag?
 
109,000.

FWIW, I'm about about to replace VCG for the second time (last time was at 60,000 about 7 years ago. In addition to noticing the birding burning oil-on-exhaust-manifold smell again, I've got a nice coating of oil on the undercarriage. Starting to wonder if my oil pan gasket needs replacing too. But I assume that wouldn't contribute to oil in the throttle body.
 
Is your driving style "aggressive"? Any exvessive "high RPM" driving?

60k (and 109k) seems awful early to have to change VCG's. There is a proper torque sequence to tightening down the valve covers. If that was not followed during the first gasket swap... then that is most likely the reason for all the oil leakage. Choice of gaskets can affect that too.

However... it also sounds like you may have an issue with excess vacuum. What kind of air filter are you using?

Do you see any smoke out the exhaust when accelerating or at highway speeds? Any high oil consumption (besides the leaks)?

It is normal to see some oil in the plastic tubes of the PCV system (those aren't vacuum lines). Plus it is normal to see oil puddled in the intake manifold when you look past the throttle body.

Does the car idle smoothly or rough? If rough... that points to a potential vacuum leak... which can create a siphon effect on the oil... or something mechanical. If the cam timing jumped a tooth... that will affect engine vacuum.

Are there any codes?
 
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Not an aggressive driver, definitely not any sustained high RPM driving. I did the first VCG replace within a year of buying the vehicle. Followed the writeup on this site to the letter. That was actually when I bought my torque wrenches to make sure I did it all absolutely perfectly, including the sequence. I used Fel-Pro gaskets. Used the opportunity to upgrade to the Accel COPs as well (I did reverse the polarity of the plugs).

Car idles smoothly. No codes. No smoke from the exhaust. The only smoke I see occasionally is some wisps from the hood cowl, which is from the oil burning off the exhaust manifold. My air filter is probably whatever the cheapest accordion-style filter Autozone had at the time. It's been at least 2 years since I changed it but it's not visually dirty. The pleats are still white and there's no solid accumulation.

I don't believe this is related, but in the interest of full disclosure, as discussed in this thread, when I did the VCGs 7 years ago I broke the hard plastic emission tube that is part of the vacuum system. I ended up replacing it with a length of rigid braided 5/16" fuel line pressed onto the plastic connectors. It has been that way ever since and (as far as I know) never posed a problem. The hose itself does not collapse or narrow at all when the engine is running and does not appear to be leaking from around the connections.

Also not sure if it's relevant, but I do have a lot of oil-related grime caked around where the oil fill tube meets the driver-side VCG, and on surrounding surfaces (don't have a picture handy but can take some later). I've always felt that shouldn't be the case but seem to recall reading other threads where it was said that's normal.
 
Most fuel injected cars always have an oily residue build-up from the throttle body to the heads. You just need to clean that with some throttle body cleaner. Luckily we are not direct injection, those engines need regular walnut shell blasting to clear the buildup all the way to the valves!
 
The filler tube to VC o-ring seepage is normal. A number of years back I installed a new o-ring. A bit tedious to do because of the locking tabs on the neck... and not being able to see inside to know where they are at. The o-ring did help... but there is still very mild seepage.

Oil, rubber, and heat do not mix. You may want to pull the braided hose off and inspect the inside to see if the rubber has deteriorated. Maybe it crumbled and the pieces created a clog somewhere???

This is starting to sound like crankcase over pressure... but not sure what is causing it. Usually it's excessive blow by... but with the milage you have on the car... that doesn't make sense.
 
Well after scraping the the goo out the intake ports and gasoline clean the intake while i was in there i had to get control of the blow by. The photo shot is from my 04. Look to the left and the 00-02 hydrualic resevoir is used to drop the mist. Aluminum air quick disconnects make it convenient to pour back in the engine. The orifix for the crankcase is around .03". The hose is rerouted from stock.the only oem vent hose is behind the maf unit. The second photo shows the npt fittings in the valve cover. The last photo is the brake anchor bracket with zerk fittings. I found the lower pins had little to no lub. So the zerks are convenient to recharge.

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theophile said:
Sounds interesting. Can you explain?
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An oil catch can is used to "catch" oil in the PCV system. If you were to pull the throttle body off ... you would see oil puddled in the bottom of the intake manifold.

When a catch can is put inline in the pcv system... (like inline with the long 3/8" i.d. hose that goes in near the rear of the intake manifold) as the oil passes through the catch can... it falls into the can... preventing from going into the manifold.

While it is helps... I don't think this is your issue though.
 
04_Sport_LS said:
This is starting to sound like crankcase over pressure... but not sure what is causing it. Usually it's excessive blow by... but with the milage you have on the car... that doesn't make sense.
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Crankcase overpressure does sound like the likely culprit, and could explain why VCGs are leaking again.

I will check the lines for blockages and see if that turns anything up. I have to admit that I am not entirely sure what the circuit flow is in the vacuum/PCV system, but I will plan to pull off all the lines and inspect. Fortunately, I have one of those remote inspection cameras that should fit in the lines so I can get a good look at the walls.
 
theophile said:
Crankcase overpressure does sound like the likely culprit, and could explain why VCGs are leaking again.
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Click to expand...
I wouldn't expect that. Take the oil fill cap off with the engine idling. Put your hand or a paper towel over the opening. Is it sucking in ever so slightly, or is it puffing out? Sucking in is normal and correct. Puffing out indicates worn out piston rings. Some oil in the intake, for better or worse, is normal.
 
joegr said:
I wouldn't expect that. Take the oil fill cap off with the engine idling. Put your hand or a paper towel over the opening. Is it sucking in ever so slightly, or is it puffing out? Sucking in is normal and correct. Puffing out indicates worn out piston rings. Some oil in the intake, for better or worse, is normal.
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Thanks Joe, that's helpful. I'll check it out. Maybe I'm lucky and everything's fine, it's just been too long since I cleaned things out.
 
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