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leaky valve seals??? and other issues

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leaky valve seals??? and other issues

 
Old 03-09-2019, 06:10 PM
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Default leaky valve seals??? and other issues

about a year ago i did a valve cleaning on my 2007 s8 v10. some valves were worse than other, had to replace the intake. i took it as face value that this was just routine maintenance and everything was "normal." i've driven it occasionally over the last year, 6000 miles or so.

when i did the valve cleaning, i didn't pull the injectors... so it's developed misfire faults, lean fuel condition faults, and injector no 9 faults. so now i'm dealing with it!!

pulled off the intake and looked at the valves. some valves have a dry layer of soot on them, no big deal. but some have a very grimey, sludgy, oily buildup on them. there was a lot of sludge when i cleaned the valves, but i wrote it off as the pcv setup was clogged. when i removed it this time, there was little to no oil from the pcv.

i've got good pressure on the cylinders. i believe it was somewhere around 210 or so on all cylinders.

i think the sludge build up is probably from leaking valve seals. altho i am open to other suggestions.

do i need to pull the engine to replace the seals?? there might be a way to pull the cams while the engine is in the car, but it might be less work to pull the engine??

also my injectors are stuck. going to see if i can get the proper injector puller tomorrow. thanks all
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Old 03-23-2019, 08:01 AM
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short of the post- what is the minimum height to raise the car to get the engine out from underneath it??

long post -

i'm trying to wrap up a few things before i pull my engine. i'd like to do this in my garage or carport, but there isn't much clearance in either. only about 7'. i don't have a car lift, so i'm thinking about doing this the way i've done my old vw's. set the engine on blocks and use an engine hoist to lift the car off the engine. but with such a low overhead clearance, i might be forced to do it in my driveway. unless someone knows the exact amount of clearance for the engine to sneak out under the car?? my best guess is that i can get about 2 1/2' of clearance.
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Old 03-23-2019, 08:19 AM
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1-2 progression of posts from diagnosing oil issue to pulling motor seems sort of extreme...

FWIW, I used to deal with valve stem seals (and guides) on early Audis' a lot. They were a weak point back in the 70's. But I have hardly heard of the issue in last 20 years.

First, use standard diagnostic techniques. What can you report there? Best one I know--and have used--is vacuum pulldown. Descend a long grade, shift down to force engine revs up (usually 3 or 2) and look for smoke out the exhaust/back window with foot off gas. At a minimum a long freeway offramp that slopes downward, but preferably somewhere in hills where you can do it over Ĺ mile or so. If it blows smoke, you are now on the trail of possible issue. No smoke, wrong track. And if smoke, you still need to assess piston rings, which would be via compression check plus looking for smoke out of exhaust in other operating scenarios like heavy acceleration.

You would also expect some oil consumption as well as some oil on plugs if issue is chronic. Do you have either/both?

I actually did stem seals on a 4.2 on one side with motor in. Technique is specialized. My issue turned out to be obscure--damaged block. Don't want to delve into technique too much w/ out confirmation of diagnostics.

On a motor like these FWIW--especially any with a fine oil separator setup--long before I was chasing oil stem seals I would probably replace the oil separator, especially if it (or relevant hoses) are positioned near the valves with more oil on them. I recall another recent post where someone cleaned one on a W12 and it really didn't do anything beyond maybe create issues. Sorry, I can't be specific for V10. I know the W12 set up (with the fine oil separators) or port 4.2 set up better.

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Old 03-23-2019, 09:11 AM
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Running a high vacuum condition and burning oil is much more symptomatic of worn piston rings/bores rather than bad valve stem seals. Quickest way to specifically diagnose leaking valve stem seals over piston rings is blue smoke during the first few seconds after a hot restart, say after a 10 min or so rest.

Hot oil will drip through worn stem seals and pool behind closed valves until you restart. Hey presto, a nice puff of oil smoke out the exhausts which rapidly clears when you start it up. Unless you have this specific symptom, you donít have worn valve stem seals.

I know this well from dealing with (and fully rebuilding) my TVR Speed Six engine. Soft valve stem seals were one of several valvetrain issues affecting this particular engine.
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Old 03-23-2019, 10:20 AM
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So, do both.

From Audi's what I describe applies--both full tear down and head only. Also correct it can just be drip down post shut down, though those will be pretty darn worn, or somehow specifically damaged. On the drip down scenarios BTW, a further twist I found is if the smoke gets worse (or better) on start up with car parked on slope, think about seals on the end of the motor (front vs. back) where the oil would flow both laterally and downward on shutdown. True seal issues I dealt with tended to be generalized across many/most cylinders anyway--as you would expect from overall wear. By contrast the available (limited) info here suggests it is more localized to certain cylinders. You could have a specifically cracked or torn seal, but I think field data would suggest that is really rare. (It was what I chased in my old 4.2 BTW, which likewise ultimately proved false). Also know that ages ago Audi changed seal design to put a tiny little spring around the center where the valve stem passes through. Most all the cases I dealt with were the early design where there was no spring; the spring helps compensate for wear over life of motor.

Again, I would not get too caught up in false paths. I suspect these kind of tests will likely come back negative. No data yet on oil consumption either. The mention of compression being okay maybe dismisses rings, but review the data cylinder by cylinder.

Big picture, all these FSI motors were first generation attempts at running motors with no fuel washing the valves. Add to it the Audi Rube Goldberg intake flap designs are long term often destined for failure in my estimation--largely due to long term exposure to oil and water crud coming in from oil vapor system over many years. Port injection wouldn't/didn't wash that away either. Only now 8-10 years later do we start to have the field data on longer mileage cycles AND cumulative time and hot cold cycles on the early FSI set ups, and some of the yet earlier 4 and 5 valve set ups where flaps came in. Valve stem seals on the other hand are nothing new, and (together with guides and now smaller valve stem diameters with 4/5V) refined over many generations of motors.

Biggest picture regardless, standard diagnostics apply. Run through all of those before anything as radical as pulling a generally functioning motor.

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Old 03-23-2019, 03:49 PM
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i'll try to qualify my conclusions a bit...

i've never seen any evidence of smoke out of the exhaust. even under heavy revs. the engine does run smooth. it does eat oil, altho the oil pan does leak a bit. i did a quick compression test awhile back. all cylinders were at about 200-210psi on the 3rd bump of the needle.

so i did a very thorough valve cleaning. polished everything to near white. replaced the intake with a brand new one. not off a junk car, but brand new old stock audi.

the car runs pretty smoothly, until recently when i was getting a cylinder 9 misfire due to a lean condition. just some clogged injectors. i wanted to service the injectors when i was doing the valve cleaning last year, but life got in the way and i didn't have the time.

i'm going to use cylinders 5&6 as my example. they are the extremes that i'm dealing with, all the other cylinders fall somewhere between these as far as oil residue.

first, cyl 6. this is what i would expect as normal carbon build up. a dry, sooty, even film.



now cyl 5

cyl 5 is nasty, oily, tar, primordial ooze misery.

the same can be seen in the spark plugs, altho not as extreme. cyl 5 spark plug is a bit brown and sooty, while cyl6 is still white and new.

here are a couple pics of the intake. theres a small amount of clean oil in the belly of the intake, as i would expect. there are no traces of heavy amount of oil coming from the oil separator.


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Old 03-23-2019, 04:17 PM
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1. Try pulldown test I mentioned--long downhill w/ some downshifting and no gas; report back.
2. Fix oil leaks if practical to eliminate that issue. Also, as a 2007 you probably have the problematic valve cover(s) that got superseded. Check for leaks there too, especially in lower corners.
3. Look at pol separation system and report back on where it feeds back into motor. From some technical publications, it sounds like near throttle bodies, which then would seem close to your #5 problematic.
4. What viscosity oil are you using?
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Old 03-23-2019, 06:04 PM
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i have done a long downhill with no throttle in a higher gear. it was a pretty long downhill, coming down the mountain by stevens pass. usually these kind of problems get compounded by the extreme downhill at high altitude at high speeds, but the engine felt smooth and there was no indication of smoke, misfire, etc. i never saw the telltale little oil specs on the rear bumper, or soot collecting on the bumper. a bit on the tail pipes, but that's to be expected. i'll work on getting my injectors sorted out and get it running, but it will take me a little while.

i'm sorry. i'm used to working on v8's. cyl 6 is the oily one, cyl 7 is the dry sooty one.

here's a quick estimation of which cylinders are sooty and which are oily -
1 - soot
2 - soot and light oil
3 - soot and light oil
4 - heavy oil
5 - heavy oil
6 - heavy oil
7 - soot
8 - soot and light oil
9 - soot
10 - heavy oil

i replaced the valve cover gaskets last year. they're in good shape and there is no oil collecting near the spark plugs or in the engine valley or running down the sides. the timing chain covers show no leaking. i was really impressed by how clean the cams and everything else was under the valve covers.i had sealed up the oil sensor in the oil pan, but it turns out that the oil pan leaks a bit.

i am running amsoil sae 5w-40 full synthetic, whatever they're expensive oil is. the oil has gotten a bit dark, as expected. but it doesn't have that doom sort of dark to it that you get with blow by. i haven't done any oil analysis, and i realize that you can't necessarily see problems by looking at the oil. until this lean fuel condition came about, i hadn't noticed indications of the engine running poorly. it's always steady, power is prompt, you could barely tell it was running at idle as it was so smooth.

thanks for your help. sorry for causing a bit of confusion on the cylinder numbers.
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Old 03-23-2019, 10:32 PM
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Got it. Just confirming we are saying the same thing on cylinder numbering as Audi does it. #1 is front USA passenger side, #5 in back, #6 front driver's side and so on.

From the documentation I looked at briefly, it was saying oil separation hose connections are tied in with or near throttles. There are conditions at high RPM that might come into play. That could fit 4, 5 and 10. Not sure about #6 without any hands on with an Audi V10. Again, I would look over oil separation system more, especially how and exactly where it ties to intake manifold.

Also look for oil smoke on start up as dvs dave mentioned. Given your issues seem to be at ends of the motor generally, if possible try cold starts over time with nose either up or down and see if under any of those scenarios you see cold start smoking--in opening 10 or 15 seconds.

One more corner case might be to look at an Audi part called variously the suction valve, suck valve, vacuum suction pump and some other things. It is fit into a vacuum line that ultimately drives the brake booster. It has a third hose where I forget routing, but probably internal galleries somehow. My old 4.2 had it and so did my D3 W12. It is not a true pump--just fancy words for a simple plastic fitting with a venturi device inside. If it malfunctions--or at least on old C5 era 4.2's and 2.7T's, for some odd reason could cause oil pull. On the W12 it comes off the drivers side intake rubber boot between the MAF and the throttle on that side. W12 one was T shaped, 4.2 was a Y shape.

Meantime, I'm not really seeing any diagnostics pointing at stem seals. No apparent oil pull, no smoking noted thus far, and compression test doesn't point to rings either.

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Old 03-24-2019, 02:53 PM
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as far as cyl. numbering, i've always seen the drivers side front is no 1, and the next one back is 2, and so on. the front passengers side would be no 6. it sounds like you're saying it's the other way around?? like this-


then the pic of the oily valve would be cyl 1 and the sooty valve would be cyl 2.

according to that layout, here's a quick estimation of which cylinders are sooty and which are oily -
1 - heavy oil
2 - soot
3 - soot and light oil
4 - soot
5 - heavy oil
6 - soot
7 - soot and light oil
8 - soot and light oil
9 - heavy oil
10 - heavy oil



so as of right now, i've wrestled all the injectors out. going to get an engine support so i can fix the leaky oil pan. i'll put it back together and run it downhill again and really keep an eye out for smoke, and perform any other tests.

couple questions -

is it worth having injectors cleaned and getting an o-ring kit?? or am i better off just buying new injectors?? i have to ask, i am a bit cheap when i'm allowed.

do i need to get an engine support bar to remove the front engine mounts to remove the oil pan?? or can i support the engine from underneath somehow??

fyi- the fine oil separator enters into the intake manifold just above cylinder 10. in this pic, that little port at the top of the pic is where the gases enter back into the intake -



bear in mind, i have not cleaned the intake out. theres very little evidence of much oil in the intake. i believe the fine oil separator is functioning properly.

i'll look into the suction valve. i think i've fooled with that on a v6 before... i have a hard time visualizing how that would cause various valves to become oily tho. it seems like the fine oil sepator or the suction valve would flood the intake with oil and the inlet butterfly before it made it's way down to the valves. on my car, it seems to be happening the other way round. the intake and inlets are clean and clear, but some of the valves are really oily.

Last edited by wizardofoddd; 03-24-2019 at 04:49 PM.
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