Thank you for info. I am in the same boat as yourself with 1 qt/700 mi on a 300D and 1 qt/800 on a 240D. I did the seals on the 300D but to no advantage, not even for a short time. I feel the same result will come from the 240D. I have another 240D and three gas MBs (560SEL, 280SE, 280) all with minimal oil consumption/usage.

I know there are thousands of cars out there with the problem.

Do you know anything about the 'Oil Baffle Plate' referred to in Fix #2 above. None of my engines have this? Also what is the 'Oil Separator' that is being referred to?

I know neither of the oil baffle plate nor the oil separator. If you find out please post the info here. I might try your fix #1 to see what happens. I wonder if the valve stem seal fix doesn't work on our cars due to the lack of negative pressure. I would have thought gravity would cause the oil to seep through but maybe that isn't enough.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Ding-ding... We have a winner.

I've done several rebuilds on OM61X engines and I've always found the same problem. The cylinder walls oval out at the top of the bore and the rings cant seal properly - this results in increased oil consumption and poor cold starting. The last OM616 engine I rebuilt had 240K miles on it and the bores were 6X out spec for taper. At the time of the rebuild the car used a quart of oil every 300-400 miles, after the rebuild (new pistons and cylinder liners) it used a quart every 6K miles. FYI at the time of the rebuild the valve guides were found to be in spec and were not changed - I did change valve seals but the old ones appeared to be in good shape.

The OM61X engines seem to have a reputation of being incredibly long lived engines and to be fair I've heard and seen examples that have over 200-300K miles of service and don't use oil but the more typical pattern is that these engines start to use oil at the 175-200K range and many will require rebuilds at the 250K mark. From a long term durability perspective they seem average at best.

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98 Dodge-Cummins pickup (123k)
13 GLK250 (135k)
06 E320CDI (323K)
16 C300 (62K)
82 300GD Gelaendewagen (54K)

Perhaps this is the place to define what "excessive oil consumption" is....
If we look in service manuals of om615/616/617 from the early 1970-ies, the manufacturer says "<0,15l/100km(or 60 miles)...
An om60X shouldn`t consume more than 1l./1000 kilometres...
...page 3:
http://www.pauldrayton.com/uploadfiles/merc/Service/W124/w124CD1/Program/Engine/602_603/18-025.pdf

The usual european diesel car(up to 2000cc) from circa Y2K-around 0,5l/1000km...
Although the numbers go down with time ,it`s still what a user(or mechanic) would call "excessive"...why do manufacturers give such high numbers ???

It is certainly true that at some point really bad guides will cause what you mention....but he did not say he was having compression problems.... he only mentioned the oil burning.. and since these are very sturdy engines and the labor is exactly the same ... in fact you can check that valve guide looseness and then simply insert the proper seals/springs/rotators putting the engine back together... I suggest these things since they are generally underappreciated as far as their importance and abuse they take over the years....

I would just add that bad valve guides won't necessarily show up on a compression check. If the valve is seated properly against the seat, which can be the case with bad valve guides, you won't lose any compression through the top end. Just like a leak down test won't necessarily indicate bad guides if the valve is seated properly. Great discussion so far.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

In conclusion I would like to say that the findings from Mr Freeh have given me very credible insight.

There is no easy fix, unfortunately, or so it would appear.

I am just going to continue to cheerfully add my oil to feed the 'taper' worm!!!!

The laws of economics answer the question. $50/yr for oil (10,000 miles) is inconsequential relative to the cost of a tear down.

I am at least satisfied that my initial scepticism about it being the guides is upheld. Every Mechanic I spoke to over the years has always retorted "the guides.....the guides".

You hit the nail on the head.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Dionysius,

Use Castrol Syntec synthetic engine oil. I used it in my 617 engine and the oil usage decreased form 4 quarts to 1 quart per 10,000 miles.

It didn't do it overnight, it took 3 years and 30,000 miles so U have to be patient.

P E H

' Advanced guide stem wear' ...no one said that seals by themselves would fix that... but since the thread has finally gotten some ' financial comparisons' and logic into it... I say again... you do exactly the same labor to go and check the guide stem wear.. if you find it unnecessary to pull the head and do major repair then you simply put NEW stem seals ( and often you should put new springs and rotators in since they are relatively cheap ) and put the valve train back together.....
Another quirk on these engines is the level the oil is maintained in the engine... too high and excessive oil usage occurs.... plenty of discussion in the archives about this...basically though...keep the oil level below half the space between max and low... AND be sure you have the proper color dipstick for your engine... it HAS happened that some PO replaced his dipstick out of a junkyard with the wrong color handle and was operating his engine with the oil too high as a result... also in the archives....
The description of the valve stem seal wear... very entertaining... but a little over the top.. another possibility if your seals wore out way too fast... that you did not install the newer gas lip style... or they were not seated properly... the idea that there could be such side to side valve stem movement that it would quickly wear out the rubber seals ... but that the valve themselves would continue to seat properly and not burn ( seating properly provides at least half of the cooling effect for the valves ) is also entertaining to visualize... but less likely to happen in the real world....

Not only entertaining but also factual. A very common problem on air cooled 911s.


Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

I drove air cooled engines about 20 years... the difference in the longevity between those and these MB diesels is off the chart... they have to have larger initial clearances due to the much greater range of thermal expansion encountered...

I recently spoke with a diesel mechanic from Ireland who thinks that Americans over rate their Mercedes diesel engines. He says that they are usually good for about 200,000 to 250,000 miles before they start burning excessive amounts of oil, and that a lot of guys in Europe will replace their Mercedes engines with Toyota engines rather than rebuild.

Otto
'79 240D 4spd

Based on what I see I tend to agree with this point of view. Are the Toyota engines also diesel?? And what is their life relative to Benz??

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Dionysius

He didn't specify whether gas or diesel Toyota engines were getting dropped into the old 123's over there, but he does favor a Toyota diesel over a Mercedes.

Otto
'79 240D 4spd