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Hmmm. That is a negative. At least it seems your problem is different then mine. White smoke is just humidity/steam. If it did not have any oil particles mixed in, I'm guessing oil is not dripping into your cylinders thru the valve guides.

This has been my assumption for my car and I have read this in other forums/posts.

So my guess is that oil is not seeping thru your valve guides when the engine is not is not running.

It must be getting into your cylinder(s) some other way.
 

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rings would be blowing blue smoke, and likely blowing your PCV plumbing off, open the oil filler cap while its idling, if its rings all kinda crap will be coming out of there. ideally, you leave the unfastened cap sitting over the oil filler hole, and the cap mostly sits there, and only dances a little. if there's engine blowby, either from valve stem seals, or rings, the cap gets pushed off.
 

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It is so sad to see how a good running car has gotten so fouled up by an irresponsible mechanic. The good ones know that you take the good with the bad. When a job goes bad, you very well could lose money on the job but you bite the bullet in the interest of keeping the customer and reputation.

At this point the car runs but smokes. It could be much worse but continuing with the car in this condition (10,000 miles?) isn't going to do it any good either.

Its time to fish or cut bait. All the well meaning folks on this site aren't going to fix your car for you.

I know this is a lousy situation and you feel like you got the messy end of the stick on this one but you have to move on. You don't seem to be experienced enough to tackle this problem yourself and don't feel bad because most people couldn't. It takes a highly qualified person with years of experience on these particular cars to figure out what has happened and to remedy it.

Honestly, if someone here told you the rings were shot, would you actually go to a shop and ask them to change the rings? Doubt it. If you became convinced the valve guides are all cracked would you jam them up the mechanic's ... well you get the idea. The logical next step is to get the car to a qualified person to find out what is wrong.

You could talk to the machine shop that did the work, and there could be a lot of value in doing this because I suspect they will stand behind their work more so than your mechanic.

The next step isn't to try to do long distance diagnostics, its to find another mechanic. And if your mechanic is as bad as he appears to be, you would be doing others in the So Cal area a solid if you were to disclose the name of the shop that caused this problem.

Sorry for being such a "cold pail of water"; I wish there was more that could be done remotely.
 

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I agree with tutebenne except, I would be cautious to take the car to another mechanic that you may or may not trust because he also may start replacing parts on you that does not need replacing trying to diagnose you problem.

I would not rule out the dealership either. I visited them a year ago to diagnose my CA smog problem. The deal was if they can fix my problem I would pay them whatever they asked. They could not, I ended up with new cold start valve, new injectors, a whole bunch of smog diagnostics and fuel treatments, adjustments, new spark plugs. Total bill was >$2000. Car was running great but did not pass smog after the work they did. Guess what, they returned all my money, no questions asked and I knew the car does not have ignition or emission parts issues after all that diagnostics.

If I were you (actually I am, because I will do these tests on my car with the 500mi/quart problem) I would still do what LeftCoastGeek suggested.
It is free and it may tell us something.

And lastly, a leak down test will also tell you something about your rings in conjunction with the standard compression test.
If what your shop is telling you is the truth you have excellent compression. If I were you, I would definitely verify that. Do it yourself it is just too easy not to.
If your compression is really that good, that just means your valves are doing a good job sealing the ports.

A leak down test will tell you if there is too much space between your piston rings and your engine block if you have excellent valves.

I believe this is also an easy test but not as easy as the compression test. This test tells you how much air is escaping between the piston rings and the cylinder wall "with precision" if you have a prefect compression. Air will always escape thru between rings and block and the leak down test tells you exactly how much. This is pretty much the gap. If it is large then you know oil can come thru there as well.

Honestly, I do not think it is your piston rings, but if you take it to a mechanic and he does not suggest this immediately, walk away and find yet another mechanic.

But first try the LCG (Sory leftcoast your name is too long) test, see if there is access blow by.
 

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I agree with tutebenne except, I would be cautious to take the car to another mechanic that you may or may not trust because he also may start replacing parts on you that does not need replacing trying to diagnose you problem.

I would not rule out the dealership either. I visited them a year ago to diagnose my CA smog problem. The deal was if they can fix my problem I would pay them whatever they asked. They could not, I ended up with new cold start valve, new injectors, a whole bunch of smog diagnostics and fuel treatments, adjustments, new spark plugs. Total bill was >$2000. Car was running great but did not pass smog after the work they did. Guess what, they returned all my money, no questions asked and I knew the car does not have ignition or emission parts issues after all that diagnostics.

If I were you (actually I am, because I will do these tests on my car with the 500mi/quart problem) I would still do what LeftCoastGeek suggested.
It is free and it may tell us something.

And lastly, a leak down test will also tell you something about your rings in conjunction with the standard compression test.
If what your shop is telling you is the truth you have excellent compression. If I were you, I would definitely verify that. Do it yourself it is just too easy not to.
If your compression is really that good, that just means your valves are doing a good job sealing the ports.

A leak down test will tell you if there is too much space between your piston rings and your engine block if you have excellent valves.

I believe this is also an easy test but not as easy as the compression test. This test tells you how much air is escaping between the piston rings and the cylinder wall "with precision" if you have a prefect compression. Air will always escape thru between rings and block and the leak down test tells you exactly how much. This is pretty much the gap. If it is large then you know oil can come thru there as well.

Honestly, I do not think it is your piston rings, but if you take it to a mechanic and he does not suggest this immediately, walk away and find yet another mechanic.

But first try the LCG (Sory leftcoast your name is too long) test, see if there is access blow by.
 

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Rocker box off ,you will see if the guides were replced or not .
And as you have the rocker box off you will be able to check the play in the guides . [As in my post above]
By the way Kevin , did the garage never show you the old gasket?
And find out who it was that worked on the head , and see what they have to say about it.
 

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Discussion Starter #28
rings would be blowing blue smoke, and likely blowing your PCV plumbing off, open the oil filler cap while its idling, if its rings all kinda crap will be coming out of there. ideally, you leave the unfastened cap sitting over the oil filler hole, and the cap mostly sits there, and only dances a little. if there's engine blowby, either from valve stem seals, or rings, the cap gets pushed off.
Tried this experiment this morning with a hot car after driving approximately 50 miles. Also of note is an occasional hunting/unstable idle, which might have affected the outcome of the test. When I removed the cap, the idle had been unsteady and a little bit of oil did spit out. The idle evened out a few seconds afterward (with the cap still loosened) and the cap just sat atop the filler hole with a slight tremor. When removed, nothing came out either. The idle also remained steady after the cap was fastened.

I did consult with one local mechanic who declined to do a compression and leakdown test saying that doing such could not definitively pinpoint the problem, that a teardown would be the only definitive way to render an accurate diagnosis, and that the car was simply not worth performing a procedure like this on. As he asked what the situation was that prompted my soliciting such a test, I believe that he (understandably) did not want to get caught in the middle of a potential dispute with another mechanic. What I think I should have been clearer about was that I was not seeking an opinion but just the raw numbers generated by these tests.
 

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A teardown? Meaning he wants to take your engine out and rebuild everything?

Before spending 30 minutes to conduct a compression test and another hour an a half to do a leak down test?

I would run away from that mechanic.

At this point other than the oil burning can you remind everyone what else is wrong with your car.
It is better if you just itemize.

As a reference my M103 also burns the same amount but I have no other complaints at all. So I keep putting a quart in every other gas tank fill (for the time being until I do a leak down test and most likely get around to get that much needed head job)
 

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Kevin you asked me if you can check if the guides are faulty .Well yes there is
You need to pressurise the cylinder and remove the valve spring .
Then hold the valve stem in your fingers and see what play you have in it ..
The shop will do this for you if you ask, But me i would go and find another competent garage and get back to the first one ,after you find any play in the valves..
No, it wasn't me that asked.

A good cylinder leakdown test will tell you the story if the valve guides are leaking and you don't have to take anything apart. Unless he's done the valve faces properly, then only under combustion would bad guides leak.......except if the guides are really sloppy and the valves won't even seat. This is just all weird for a supposedly rebuilt head. I mean who would do a valve job and leave in old guides and why is the oil consumption worse now than before with the same head?? Maybe even the theory given that you have a different head in there...geez.

Kevin
 

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This is just all weird for a supposedly rebuilt head. I mean who would do a valve job and leave in old guides and why is the oil consumption worse now than before with the same head??

Kevin
Exactly. What else has occurred that we don't know about? What procedures did the mechanic use that we aren't aware of? Its just an endless discussion about a set of oily sparkplugs. There are very few causes of this; some more likely than others.

I am convinced there is much more to this story than what is in this thread (and that the OP isn't aware of either).

The best suggestions I can offer at this point are:
- is it possible that one of the Benzworld members in So Cal to take a look at this car to see what can be learned through a visual inspection?
- can a So Cal member recommend another Indy shop that is qualified to take over the repair of this car while maintaining some sympathy for what the owner has gone through?
 

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I decided to do LCG's positive air pressure test on my'89 M103 engine by opening the oil filler while the engine is idling.

I noticed that there is negative pressure (vacuum) in the valve cover.
I also decided to close the air filler and take off the valve cover breather hose from the air filter box and sure enough if I cover it with my hand vacuum develops there over time.

Is this the expected behavior? I thought the valve box would have a neutral air pressure under normal conditions.
 

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yeah, there's a 2 stage reed valve in the PCV that intentionally creates a vacuum if everything is working well. if you have excess ring blowby, it will cancel this and blow the oil cap off. lots of engines do this...
 

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So considering the results of your tests, (compression test and crankcase pressure check) the compression rings appear to be in good shape.

There is a remote possibility the oil scraper rings are causing oil to run up the cylinder passed the compression rings. This is highly unlikely since you reported all 6 cylinders have fouled plugs. Is it possible the scraper rings all failed during the month or so following the completion of the head job? I wouldn't put money on that one.

So you seem to be back to suspecting the problem resides within the cylinder head.

FYI, as far as I know the '89 M103 doesn't have a PCV valve. The crankcase is vented directly to the air filter housing through the large rubber hose. You might remove the air filter assembly and with the engine off, push the round air flow meter flap fully down so you can peer into the air flow meter casting. You would be looking for an accumulation of oil (It should be dry). Let us know what you find.
 

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Discussion Starter #35
Exactly. What else has occurred that we don't know about? What procedures did the mechanic use that we aren't aware of? Its just an endless discussion about a set of oily sparkplugs. There are very few causes of this; some more likely than others.

I am convinced there is much more to this story than what is in this thread (and that the OP isn't aware of either).

The best suggestions I can offer at this point are:
- is it possible that one of the Benzworld members in So Cal to take a look at this car to see what can be learned through a visual inspection?
- can a So Cal member recommend another Indy shop that is qualified to take over the repair of this car while maintaining some sympathy for what the owner has gone through?
I am going to visit another mechanic this morning (with the car in question--something I didn't do previously). Called the dealer (in West Covina, CA) yesterday, quoted $250 for the test--which I don't have a problem with if it will give me some definitive diagnosis--but was also told once again that it will not isolate the origin of the oil burning.

There were a lot of other things that went on with this job, so I'll just tell the long-winded story from before the job until now.

1. Bought the car at 112000 miles, Aside from some occasional no-start and stalling issues, it ran very well. I had a C280 from new in 1994 as well as a 300E-2.8 from ~75000 miles in the early 2000s and the running characteristics/sound/feel were nearly identical. That's what I used as my baseline. Various relays and fuses were replaced, as well as the MAF and ECU. I also bought a used throttle actuator, but it was never put into the car. I had hoped to have that done when the head job was carried out, but the mechanic didn't feel it was a necessary thing to do. I also had some suspension work done (control arms, tie rods) but doubt this is relevant to the situation.

2. I don't really remember the exact chronology here offhand, but the head gasket started leaking around 120-130000 miles. About a pea-sized drop on the garage floor every morning. The oil loss amounted to about a quart every 2500 miles. There was no oil burning or smoke. I inquired about doing the head gasket at that time, and the mechanic advised me that the repair was unnecessary and to wait until it became more pronounced.

3. I received word that an MB shop I dealt with a long time ago was being reconstituted and since some of the family members of the proprietor are friends, I decided to give the shop a try. I did ask about sourcing my own parts prior to the job and was quoted a labor rate of $1000 for the head removal and replacement, as well as $1000 for the head rebuild plus whatever the cost would be to replace any bad valves if they were present. I think it is worthwhile to note that except the head and valve cover gaskets, all of the guides and seals I supplied were returned to me, so I presume that the machine shop declined to use these parts, which is understandable. I received a call from the mechanic stating that 7 valves were bad and needed to be replaced. I gave the authorization to proceed (it took about another two weeks just to get the head back from the machine shop). The total for this work, excluding the parts I supplied, was roughly $2900. The head was warrantied for 12 months/12000 miles. The car had roughly 135000 miles at that time.

4. Many other parts were replaced, including the water pump, wiring harness, fuel lines, heater hoses at that time. The major service was also performed and I also had some more suspension work done. The flex disc was also replaced. The cost of the entire job while the car was in the shop for more than a month, again excluding the parts I sourced, was somewhere around $4500-$5000. The strut mounts have already failed, but I take responsibility for that as I supplied those.

5. When I collected the car at the conclusion of the job, there was copious grey smoke coming from the tailpipe. I went back to the shop. The mechanic said these were residues that would burn off in time. They subsided somewhat but the smoking never went away completely.

6. After driving the car approximately 300 miles, the oil light came on. I was about 10 miles from the shop, on the freeway. I rushed to the shop to alert them of the matter. The oil was topped off and no answer was given for the rapid consumption/loss of oil. I will note that they were using synthetic 5W/30 oil which I thought was strange for this car, but the prior shop, also an MB specialist, used the same kind of oil, so I didn't question it. I may have ideas, but they are the experts. However, I became suspicious and decided to check the oil frequently. The car was burning about a quart every 400-600 miles.

7. I returned to the shop several times and the proprietor was either not present or too busy to deal with me. I relayed the problems to the workers, who relayed my messages to the proprietor. The answer I got was that the bottom end of the motor must be bad. My contention was that the car sat intact in the shop for a good week before the head was even removed, and disassembled for many weeks--was there no way to assess the bottom end and explore other options before proceeding with the head rebuild? I never received any other answer except that the top end of the motor was redone as requested.

8. The car started to develop an unsteady/hunting idle when hot after a few thousand miles, and even would die immediately upon being started. The fuel pressure regulator and starter were replaced. That problem is very intermittent but continues, and I seem to be able to overcome it by applying the throttle for about 30 seconds immediately after the car is started. The car has also started to backfire occasionally and give resistance to acceleration. I am just assuming that the catalytic converters are starting to plug up from all of the oil consumption.

For awhile I just decided to let go of the matter since I was getting nowhere, but now that 9 or 10 months have passed and I've been living with this on a daily basis with 10,000 miles on the clock, I decided that I needed to demand that the proprietor sit down with me, discuss this issue, and take the car for a couple of days to pinpoint the problem before the "warranty" runs out and we "discover" that the valves have failed. This was last week when I initiated the thread.

I will cut this short for now as I have to leave for work (and stop by this other shop on the way there) but generally speaking, however, the car still seems to run relatively well despite these problems. I'm not sure I would trust it for very long drives, but I do use it to transport large items, which is why I wanted a wagon. I drove it in excess of 100 miles on Sunday and it didn't give me any major problems, but the idle did start to hunt when the car was hot. I tried the oil cap test while the idle was hunting and oil did come out of the opening. After a few seconds, it stabilized, and nothing more came out. The cap fluttered slightly but didn't dislodge.

If it's the rings, it's the rings. Nothing I can do about that. I still wonder why this possibility wasn't brought up before starting the job to set my expectations. In other words, "just so you know, the car might burn oil after this job because your bottom end is old, do you want to continue?"

Again, I realize there are other symptoms here that may or may not be related to the oil consumption. If they are not related, I would like to focus on the oil consumption issue because this is my principal concern. I thank all of you for your input and insight with this!
 

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Stradivari, I do not mean to hijack your post, especially since mine is a M103 not an M104.

However, I'm hoping that my finding last night might help you as well.

Last night when I did the oil filler pressure check I reported there is vacuum there if the breather hose is plugged than a vacuum is developed in the valve cover, slowly. I though it would be positive pressure, as I thought the breather hose is there venting positive pressure to the intake, but contrary to my belief it is the opposite, it is breathing air in to the valve cover box, slowly.
Maybe this is all normal.

However, here is an oddity that involves oil burning. If I plug the breather hose and let some vacuum develop in the valve cover even for a minute or two the car starts coughing oil from the tailpipe. Very similar to the case when the car is left overnight and it coughs oil during the warm up period.

Is this not a strong sign that oil is actually getting thru the valve guides (easier with the vacuum) and into the cylinders?

If you agree is this not a test that is a straightforward test to check the valve guides that is not very invasive?
 

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... Last night when I did the oil filler pressure check I reported there is vacuum there if the breather hose is plugged than a vacuum is developed in the valve cover, slowly. I though it would be positive pressure, as I thought the breather hose is there venting positive pressure to the intake, but contrary to my belief it is the opposite, it is breathing air in to the valve cover box, slowly.
Maybe this is all normal. ...
On the M103 the vacuum that you detect with the breather hose opening blocked is perfectly normal.

The idle air is guided through an airduct system of it’s own within the intake manifold flange, encompassing each injector. And on the M103 this air duct system is connected to the valve cover via that small rubber hose next to the breather hose. It’s actually a second breather hose, sized to a dimension suitable to the gas pressure in the crankcase during idle. It sucks in fresh filtered idle air via the main breather hose.

Btw … I wouldn’t block the breather hose opening too often / too long while the engine is running. The vacuum that’s created inside the crankcase that way can damage the crankshaft seal rings … and the camshaft seal ring.

H.D.
 

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Discussion Starter #38
Just tried dolucasi's recommendation. Didn't sense any vacuum or blowby (nothing came out of the opening either, the cap didn't even have any tremor, and a hand placed over the opening indicated neutral pressure).

Disconnected the breather hose from the airbox with the MAF still attached and got immediate suction from the grate at the anterior end of the MAF.

The suction was immediate, so I didn't prolong anything either.
 

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On the M103 the vacuum that you detect with the breather hose opening blocked is perfectly normal.

The idle air is guided through an airduct system of it’s own within the intake manifold flange, encompassing each injector. And on the M103 this air duct system is connected to the valve cover via that small rubber hose next to the breather hose. It’s actually a second breather hose, sized to a dimension suitable to the gas pressure in the crankcase during idle. It sucks in fresh filtered idle air via the main breather hose.

Btw … I wouldn’t block the breather hose opening too often / too long while the engine is running. The vacuum that’s created inside the crankcase that way can damage the crankshaft seal rings … and the camshaft seal ring.

H.D.
Thanks for the helpful comment H.D. The question remains though, if one artificially induces some vacuum under the valve cover and the car coughs up oil, is this a sign of anything or is it a sign that valve guides are shot and in normal conditions without this vacuum, oil may still get thru the valve guides?

I only let the engine idle for a minute, no more and there was a large oil stain under the exhaust pipe.
The only other time this (oil stain under the exhaust pipe) happens with my car is during warm after an overnight cool down.
 

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Just tried dolucasi's recommendation. Didn't sense any vacuum or blowby (nothing came out of the opening either, the cap didn't even have any tremor, and a hand placed over the opening indicated neutral pressure).

Disconnected the breather hose from the airbox with the MAF still attached and got immediate suction from the grate at the anterior end of the MAF.

The suction was immediate, so I didn't prolong anything either.
And was there any oil stain under your exhaust after this experiment?
 
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