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  #1  
Old 06-17-2001, 03:01 AM
EADG
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My oil light came on yesterday, I added 1 liter of oil. I had an oil change 3000Kms ago, due for anouther this week. I cange the oil and replace the filter every 3500Kms. I decided to find out were all the oil was going this afternoon and first thing I did was pulled the plugs, (replaced 10,000Kms ago) all were good except one. The plug from cylinder #3 was a horrid mess - completly oil fouled. A quik search through the archives on this site confirmed my prognosis; valve guide seals/cylinder wear, that explains the oil loss. While examining the fouled plug I noticed 1/3 of the ceramic surrounding the anode was missing. I have some questions; How do I determine valve problems as opposed to a worn cylinder wall/rings? What happened to the ceramic that broke free from the plug? Is it in my piston chamber or expelled with the exshast gasses? What kind of damage can it cause if it remains in the piston chamber?

1991 300E 165,000Kms

Sleeping uneasy tonight...
Cheers for now
EADG

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  #2  
Old 06-17-2001, 12:34 PM
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Rest easy. A cylinder leakdown test will determine if your valve guides are worn or if in fact you have cylinder leakage also (highly unlikely). The most common cause is the valve stem seals getting old and letting oil pass by. You may try new seals first or you could opt to go ahead and have a complete valve job done.

The ceramic missing from your plug was probably incinerated during combustion.
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Scott Diener
89 300E
93 300E
92 Volvo 740 Wagon aka "Mutt mover"
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  #3  
Old 06-17-2001, 01:02 PM
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Location: Suwanee, GA, USA
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This 99.999% caused by a leaky and worn valve guide.

I have done hundreds of valve jobs on these with great results. After the valve job, the consumption will usually be about 1/2-3/4 a quart between oil changes.
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ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS
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  #4  
Old 06-18-2001, 05:55 PM
EADG
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Thanks for the reply chowpit and Benzmac. The valve seals comes as no big surprise since I was aware of other people on this bourd having had the same problem. I'll be calling 2 MB dealerships and a couple of indipendants for pricing and sheduling.
Benzmac, since you've done many, many valve jobs in the past what dollar range am I looking at to replace the seals on all 12 valves?

Cheers for now
EADG
'91 300E
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  #5  
Old 06-18-2001, 07:48 PM
WDurrance
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Hi,
First, besides eliminating other possibilities, how would a leak down test tell you anything about the valve guides?
Though they should help, the stem seals are a temporary fix for a 300E with that kind of mileage. The problem is that as the guides wear the hardened(less pliable)stem seals are bot able to deal with the added axial movement. You might get 10K miles with less oil consumption, but plan on a valve job...nothing lasts forever.
Regards,
Randy D.
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  #6  
Old 06-19-2001, 12:17 AM
dlswnfrd
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Not All 300Es

Brother of the Benz, WDurrance
You can not class all 300E with the 103983 engine with the miles EADG has on his engine requiring the valve guides replaced.
The life of the guides and the seals is directly related to oil change frequency and combustion chamber pressure(heavy throttle).
There are more with higher miles that don't require replacing having had the proper maintainance and correct driving technique that those that do.
My 1987 W124030 with 176,000 miles does not use oil between changes. That's to say it isn't low at the oil change mileage, 4-5000 miles for highway type and 3-4000 miles for city driving.
Given a second chance,and changing the oil as recommend by the authors in Starr magazine's technical section, changing driving habits,EADG may get an additional 100,000 miles before the lower section may need service.
Good luck with your oil consumption problem.
Go easy on the throttle to reduce the strain on the valves as they are slammed into their seats from the combustion pressure, and who knows what may happen.
Happy Trails Beep Beep from The Spiderman in Houston!!!
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  #7  
Old 06-19-2001, 06:05 AM
EADG
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I just want to restate my car's milage in miles...
I change the oil every 3500Kms = 2200 miles
The odometer reads 165,000Kms = 103,000 miles

Cheers for now
EADG
'91 300E
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  #8  
Old 06-19-2001, 07:35 AM
LarryBible
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The cylinder leak down test does not confirm that the valve guides are the problem, but it can eliminate ring and cylinder wear as the problem, which would leave valveguides as the most likely culprit.

I'm sure that some of the valve guides/seals in these cars (like Mr. Swinford's) live a normal life with proper maintenance and oil changes, but it is a commonly known deficiency as Donnie has said. If the leak down test shows good compression, where else could the problem possibly be? The integrity of these engines is mostly in the head, if the cylinders are in good shape, money and time will be well spent on the head. A valve job with new guides and seals will most likely make this engine like new.

My $0.02,
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  #9  
Old 06-19-2001, 09:28 AM
dlswnfrd
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Money Well Spent

Brothers of The Benz
Discussing the 103983 engine;
How many times can the cylinder head be rebuilt to a lower end rebuild.
From all that we read, the lower end doesn't really show wear at 200,000 miles if maintained properly.
I've got my fingers crossed hoping to get the 200,000 miles on the top side.
What became of the old reliable dry/wet compression tests? This always identified the seperation between the piston rings and the valves.
As Larry has noted, the weak link is the cylinderhead. This isn't just for this engine but all spark ignition engines, so anything that can be done to take care of it is well worth the time and expence.
The most damaging item to the lower end is an uneven force produced by pressures from uneven cylinders. This unbalance has damaging effect on the transmission as well.
Larry's $0.02 is well received, and I'll give him some change.
Happy Trails Beep Beep from The Spiderman in Houston!!!
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  #10  
Old 06-19-2001, 09:51 AM
LarryBible
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Mr. Swinford,

There was a good article some months back in the Star Magazine regarding the bottom end of modern MB engines. In the article, their claim was that unless the engine is driven fast alot, such as on the Autobahn, the bottom could be good for a couple of head rebuilds.

This is interesting, but as you eluded to early in this thread, the maintenance attitude will play heavily into this.

Last summer I did the cylinder head on my '88 103 engine. As I recall, the engine had about 175K miles or so, and there was no ridge that you could feel with your fingernail and there was prominent crosshatch. The engine turned out great after I got it back together.

With YOUR maintenance regimen, I expect your engine to live somewhere close to "forever".

Have a great day,
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  #11  
Old 06-19-2001, 02:29 PM
EADG
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I've booked an appiontment with the MB Dealership in Burlington Ontario (has anybody dealt with them??). They will preform a leak down test on all 6 cylinders next Monday. If in fact it is the valve seals that need to be replaced I'll take the oppritunity to replace the seals on all the valves. With the rocker cover off and the seals removed is it possible to measure the wear on the valve stems or does the head have to come off and valves be removed to measure this?
The labour rate is $82CDN/hr (~ $55US) Does anybody know the cost of parts; seals guides and valves?? I believe they said 5 to 6 hours to replace the seals, how much more time would it be if they replaced the vaulves too?

Some of you may have noticed that I'm changing the oil and filter quit frequently, 3000 - 3500Km... I've destroyed a 525i ( funny story about valve seals, smoke and a mechanic - I'll leave that for anouther day though)and 2 280E engines due to oil. I'm NOT going to blow an engine this time 'round.

Cheers for now
EADG
'91 300E
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  #12  
Old 06-19-2001, 02:38 PM
LarryBible
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I hate to dowse this approach with ice water, but if there is so much oil reaching the combustion chamber that a plug is oil fouling, and indeed the oil is getting by the valves, I expect seals won't fix it, it will probably take guide replacement.

However, you should try to get Donnie's experience factored in here, I know that he has seen valve seal replacement accomplish a lot. But it seems to me that this is too much to ask. To fix it right, I believe you should pull the head, replace the guides and do a valve job. If the leak down shows no leakage past the rings, the complete valve job approach should result and a very good engine.


My $0.02,
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  #13  
Old 06-19-2001, 03:28 PM
Icesailor
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EADG,
Non Benz related but, I have sailed around that end of the pond a bunch and Burlington is a very nice place in the world.

Rick
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  #14  
Old 06-19-2001, 11:24 PM
dlswnfrd
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It's a Down Right Rotten Shame

Brothers of The Benz
It's unfortunate that all of us haven't had the Joy of buying their Benz new.
But, at least you have a Benz.
There are so many used Benzs on the market that have been neglected and had their heart run out all of their lives.
Those of us who bought our Toy new enjoy it more with each added mile, and wouldn't part with it for anything.
Except for those who are able to purchase a new Benz each year, and then being the fortunate buyer to get such a deal after the first depreciation has taken a chunk out of the retail price, buys a gem.
Then there is the M/B as mine and so many others that have been taken care of and feel bragheart when boosting about the excellent service we have gotten from it.
It appears that some of the used Benzs that members have purchased have really been neglected and unless it was purchased at the right price, the new owner really becomes disenchanted owning his M/B.
People don't get rid of their cars if there is nothing wrong with them. No, just the opposite, they neglect the problem areas until there are so many that they must get rid of it to save the expence of repairs and those who buy these cars from individuals buy that mans problems.
There is the coined phrase "Have Records".
Are they truthful?
If I was to buy a used Benz today, it would have to come from a M/B Dealer. I would pay more but I would get more.
Dealers get rid of their "DOGS".
These are found at Happy Charlies Exotic Cars.
I don't know how to close and not hurt someones feelings so,
Happy Trails Beep Beep from the Spiderman in Houston!!!
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  #15  
Old 06-20-2001, 12:31 AM
WDurrance
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Hi All,
Sort of a side note, but...the first time I saw the cam and rocker setup I was reminded of BMW's arrangement. The rocker travels in an "arc", putting pressure on the walls of the valve guides. I used to see lots of BMWs with worn guides at a relatively low mileage. I also did quite a few 300Es under warranty....there would seem to be a connection there somewhere since oil consumption problems went away when the cam and valve arrangement changed.
Just a Thought,
Randy D.

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