Oil smoke upon starting
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Oil smoke upon starting
Hi,
My car is a low mileage 2007 with the 5.5L gasoline V8. It’s back from the Mercedes shop after its yearly service. Actually, I managed to pick it up just the day before our country entered the lockdown period. The shop is now closed and I won't have any access to them for some time.
Now working from home, I hardly used the car since then but I discovered over the week-end that the engine now emits a big puff of burnt oil smoke upon start-up. That never happened before. Engine otherwise runs fine.
I’ve already ruled out an oil pan overfill. I’m leaning towards a casing breather and oil recirculation issue. I don’t have any tech documentation about this car. Could someone show me a diagram of this system ? The spark plugs have been changed as part of the maintenance performed. Is there a chance that some plumbing has to be disconnected or moved in order to get access to the plugs ?
Thanks for your help and stay safe.
My car is a low mileage 2007 with the 5.5L gasoline V8. It’s back from the Mercedes shop after its yearly service. Actually, I managed to pick it up just the day before our country entered the lockdown period. The shop is now closed and I won't have any access to them for some time.
Now working from home, I hardly used the car since then but I discovered over the week-end that the engine now emits a big puff of burnt oil smoke upon start-up. That never happened before. Engine otherwise runs fine.
I’ve already ruled out an oil pan overfill. I’m leaning towards a casing breather and oil recirculation issue. I don’t have any tech documentation about this car. Could someone show me a diagram of this system ? The spark plugs have been changed as part of the maintenance performed. Is there a chance that some plumbing has to be disconnected or moved in order to get access to the plugs ?
Thanks for your help and stay safe.
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S500
could be anything....
drive too gently when you run a car in, and the piston rings never bed in correctly.
don't let it warm up before ripping it, you wear it out
don't exercise it often enough when fully warmed up
use the wrong oil,
not changing it often enough,
nasty fuel with out enough additives to keep the insides clean / in good condition
what is low mileage?
too low might be part of the issue… in the good old days you had very durable cast iron cylinder liners... then they decide there's better thermal transfer and more closely matched tolerances if you coat aluminium block cylinder walls with a durable coating. Its true it can work better but not enough that it warranty the downside... driving too hard from cold, the wrong fuel, a minor glitch of the cooling system. or the wrong amount of time not turning over the engine and the whole thing is trashed.
the early days (mid 90's) the process and coating is not as good as today. many BMW had severe issues with their first V8s and certain countries fuel additives, these destroyed the coating and they all fell to bits. Many cars secretly got new engines when the car was in for a service. I've not heard of an issue with Mercedes but the risk is there...
it'll be sold as emission / power friendly... what they mean is it falls to bits to a nice time line so we sell more cars
drive too gently when you run a car in, and the piston rings never bed in correctly.
don't let it warm up before ripping it, you wear it out
don't exercise it often enough when fully warmed up
use the wrong oil,
not changing it often enough,
nasty fuel with out enough additives to keep the insides clean / in good condition
what is low mileage?
too low might be part of the issue… in the good old days you had very durable cast iron cylinder liners... then they decide there's better thermal transfer and more closely matched tolerances if you coat aluminium block cylinder walls with a durable coating. Its true it can work better but not enough that it warranty the downside... driving too hard from cold, the wrong fuel, a minor glitch of the cooling system. or the wrong amount of time not turning over the engine and the whole thing is trashed.
the early days (mid 90's) the process and coating is not as good as today. many BMW had severe issues with their first V8s and certain countries fuel additives, these destroyed the coating and they all fell to bits. Many cars secretly got new engines when the car was in for a service. I've not heard of an issue with Mercedes but the risk is there...
it'll be sold as emission / power friendly... what they mean is it falls to bits to a nice time line so we sell more cars
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S500
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Hi Botus.
I don't think this has anything to do with a gradual wear. This was really one day no smoke, next day smoke on. Funny you're mentioning the BMW issues. Years ago I encountered the same kind of issue on a 4.4L M62 (but much worse), was indeed a diaphragm failure in the de-oiler / casing breather located into the inlet manifold.
This afternoon I found out that the air filter housing wasn't properly seated on the air intake / mass flow sensor housing, as the delicate mechanic who handled the task of reinstalling the box just bent the two rear metal clips on themselves ! I prefer not to imagine how much weight he had to impose on this plastic part to achieve such a result ! I haven't had enough time to reinstall everything and give it a try, although I'm not sure that it could be related, even if it created an unfiltered air leak. Btw, low mileage is 40000 mi.
I don't think this has anything to do with a gradual wear. This was really one day no smoke, next day smoke on. Funny you're mentioning the BMW issues. Years ago I encountered the same kind of issue on a 4.4L M62 (but much worse), was indeed a diaphragm failure in the de-oiler / casing breather located into the inlet manifold.
This afternoon I found out that the air filter housing wasn't properly seated on the air intake / mass flow sensor housing, as the delicate mechanic who handled the task of reinstalling the box just bent the two rear metal clips on themselves ! I prefer not to imagine how much weight he had to impose on this plastic part to achieve such a result ! I haven't had enough time to reinstall everything and give it a try, although I'm not sure that it could be related, even if it created an unfiltered air leak. Btw, low mileage is 40000 mi.
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2018 S450 4Matic, 2020 GLE450 4Matic, 2010 S550 4Matic(sold), 2012 ML350 4Matic(sold)
Could be a lot of things.
Worn valve guide seals is a potential.
A different oil is another. You may have had worn valve guides all along and not noticed it because of the oil used in your car.
If this shop put in a different oil this time, it could exhibit the oil smoke more than another brand/type/viscosity.
Does this happen only after a short drive and not after you take it out for a nice long trip (more than 30 minutes)?
My car has this on a subsequent start if I only run my car for a minute or two before shutting it down.
Please watch the pattern more and that will help with diagnosis.
Tom
Worn valve guide seals is a potential.
A different oil is another. You may have had worn valve guides all along and not noticed it because of the oil used in your car.
If this shop put in a different oil this time, it could exhibit the oil smoke more than another brand/type/viscosity.
Does this happen only after a short drive and not after you take it out for a nice long trip (more than 30 minutes)?
My car has this on a subsequent start if I only run my car for a minute or two before shutting it down.
Please watch the pattern more and that will help with diagnosis.
Tom
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S500
I did read the other day about changing part of the breather system on this engine... as though part of routine maintenance
mine uses a bit of oil when the oil has got a bit older. Use the decent merc rated stuff and its 12k miles and 2 years... but after 14 months and 6k miles mine can use 1/2 litre before the next change
it does seem to breath quite heavily at different times. When I first got it at 42k miles, if you ripped it down the road the dip stick popped up an inch. Odd design as the O ring is nowhere near the tube. With 1 mm gap all the way round. Funny enough hasn't done it in the last 3 years
wear in the a bore liner would be a sudden failure (once its gone its gone). The amount of AMGs that seize and nip up bending a couple of rods and destroying the block if you violently rip it from cold is dramatic and 20k repair for a 100 yard dash
mine uses a bit of oil when the oil has got a bit older. Use the decent merc rated stuff and its 12k miles and 2 years... but after 14 months and 6k miles mine can use 1/2 litre before the next change
it does seem to breath quite heavily at different times. When I first got it at 42k miles, if you ripped it down the road the dip stick popped up an inch. Odd design as the O ring is nowhere near the tube. With 1 mm gap all the way round. Funny enough hasn't done it in the last 3 years
wear in the a bore liner would be a sudden failure (once its gone its gone). The amount of AMGs that seize and nip up bending a couple of rods and destroying the block if you violently rip it from cold is dramatic and 20k repair for a 100 yard dash
Last edited by BOTUS; Mar 31, 2020 at 02:02 PM.
Thread Starter
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Hi,
Problem solved. Took me some force to pry these clips open again, the guy really had to push hard to bend them flat as he did. It was indeed the air filter housing not being seated properly that disturbed the casing breather circuit and inlet airflows, everything is back to normal once reinstalled properly. As hinted from the start, no thrown condrod through the casing or other horror story to report here
But I can't believe that MB shop. Highest man hour rate in town, working on one of the biggest engine of their line up (even if a few years old) yet acting so carelessly... Seems that I have to draw the same sad conclusion than before about my BMW dealer : they are used to work on the diesel 1 series / A Class and are useless, or even harmful, when it comes to working on the top of the line offers from their brand.
Problem solved. Took me some force to pry these clips open again, the guy really had to push hard to bend them flat as he did. It was indeed the air filter housing not being seated properly that disturbed the casing breather circuit and inlet airflows, everything is back to normal once reinstalled properly. As hinted from the start, no thrown condrod through the casing or other horror story to report here
But I can't believe that MB shop. Highest man hour rate in town, working on one of the biggest engine of their line up (even if a few years old) yet acting so carelessly... Seems that I have to draw the same sad conclusion than before about my BMW dealer : they are used to work on the diesel 1 series / A Class and are useless, or even harmful, when it comes to working on the top of the line offers from their brand.
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S500
you pay 200 dollars an hour (the talent at reception and the coffee are OK), the building is impressive but the person working on your car is one up from guy at school who couldn't read... and he's on 14 dollars an hour if lucky
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S65 GL320CDI GLS63 80 Series Landcruiser
This is why I like to do all my own maintenance. Plus if I see something broken or leaky while I'm in there I fix it. Or if something is really dirty I clean it. I even take my wheels off and bring them to the dealer without the car for new tires. Don't want them banging up the wheels taking off the lug nuts or torqueing them down too tight. True story I broke a normal socket (not impact) with a breaker bar trying to get a lug nut loose after dealer did my tires on our old GL.
