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I have a well used but strong running '81 300D with 210k miles. She has gone through a couple owners so I can't speak specifically to the quality/frequency of the maintenance but I know between the previous owner and I, over the past 50k miles there have been regular 3000 mile oil/filter changes and routine PM done.

It's currently burning about 1 quart every 500 miles and has for as long as I've had it.

With 1 quart per 500 miles, can the motor still be considered healthy for the miles and have another 100k in her? or is she nearing the end?

Very minor leaking. A few drops under the car when parked for a whole day so the oil is being consumed not leaked out.
 

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1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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You know what they say about old mercs....if it stops leaking oil, start worrying.


:D
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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So, is it leaking or is it using oil? There's a bit of difference regarding the condition of the engine. The leaking is usually due to age; using is due to wear.

You know what they say about old mercs....if it stops leaking oil, start worrying.
:D
I've never heard that said about any Merc, not even old Mercs. But I have heard it being true about British cars, even new British cars. Yes, even Rolls-Royce.
 

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1982 240D, 1985 280E Euro, 1989 300TE, 1992 300D 2.5 Turbo, 1992 300SD
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I got a 82 240D that burns that much too! 225K miles but strong and stubborn as a mule...:grin

I've done some research on why mine burns that much (sometimes even more) oil and some say its the Valve stem seals or the little o-ring in the supply lift pump, but to suspect that o-ring is to see if your fuel is contaminated with oil (by checking your pre-filter and see if its a greyish (?) color)

However, I've noticed for me if I had a bottle and a half of STP oil additive during an oil change, it'll take 1000 miles before I have to add any oil, so give that a try and see if adding some kind of oil additive helps it consume less. If it does, I wanna say its valve stem seals or rings... I also hear that doing a leak down test will answer most questions :smile
 

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So, is it leaking or is it using oil? There's a bit of difference regarding the condition of the engine. The leaking is usually due to age; using is due to wear.

It's using oil. The leaking is only a few drops after a day or two in the driveway.
 

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'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
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If it leaks oil slowly when standing, it will leak oil more quickly when under pressure. Besides, leaks are easier and cheaper to fix. I'd follow whiranrat's recommendation, then I'd fix the most likely leaks - lower sump gasket, drain plug, valve cover gasket - and see if it makes a difference.

If an engine pulls strongly, it's unlikely that it's worn enough to use a significant amount of oil. My first 240D was so worn that she had to be towed to start, and she still didn't use oil. By contrast, my 300D starts and shuts down with authority, but the lower sump is leaking about 2 quarts every 3k-4k miles. (I'll fix that during the next service.)
 

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I've never heard that said about any Merc, not even old Mercs. But I have heard it being true about British cars, even new British cars. Yes, even Rolls-Royce.
Yeah, that was the Land Rovers, something like they use so much oil, they do their own oil change or something like that :D

What kind of oil is it using? It might be to your advantage to put in a slightly heavier oil, or a non-synthetic, or be more gentle. Mine only uses oil when I try to take it on the highway (or when I let my buddy use it for 6 months). Driving normally, it's pretty good. By gentle I mean, keep the revs down, shift low.
 

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What kind of oil is it using? It might be to your advantage to put in a slightly heavier oil, or a non-synthetic, or be more gentle. Mine only uses oil when I try to take it on the highway (or when I let my buddy use it for 6 months). Driving normally, it's pretty good. By gentle I mean, keep the revs down, shift low.
Part of the reason for the question is that I'll be taking it on a long drive over 3 days, on the highway. I'm moving and it isn't cost effective to have it shipped. I'll just check the oil frequently and take it easy since I won't have time to go through the seals and potentially leaks between now and then.
 

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If it's using oil, it's not seals, it's worn bores, the oil becomes part of the combustion process (as I understand it), a thicker oil is less likely to get past the piston rings.

You don't say what oil you use, I use the synthetic Rotella 5W40, but if I was doing a lot of highway, I have a conventional 15W40, that I buy from the local farm supply place at $15 for 2 gallons. That should get you there at a quart per 500 miles :D

This dependent on the temperature range you'll be seeing on your trip of course.

http://www.ruralking.com/rural-king-heavy-duty-diesel-engine-oil-15w40-2-gallon-75072.html
 

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1984 280sl 5spd, 02 E320 4matic, 79&79 450sl part-out, 78,79,81,83 300CD, 79 280CE
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I got a 82 240D that burns that much too! 225K miles but strong and stubborn as a mule...:grin

I've done some research on why mine burns that much (sometimes even more) oil and some say its the Valve stem seals or the little o-ring in the supply lift pump, but to suspect that o-ring is to see if your fuel is contaminated with oil (by checking your pre-filter and see if its a greyish (?) color)

However, I've noticed for me if I had a bottle and a half of STP oil additive during an oil change, it'll take 1000 miles before I have to add any oil, so give that a try and see if adding some kind of oil additive helps it consume less. If it does, I wanna say its valve stem seals or rings... I also hear that doing a leak down test will answer most questions :smile
My 78 300CD, burns about that same amount of oil 1Qrt/500miles , at interstate speeds 75/80 MPH. Less at the lower speeds that I usually drive. It is not leaking the oil, so has to be burning it. I have replaced my valve stem seals, and that has not improved the loss of oil. While replacing seals, valve stems seamed to be fairly loose. Have also tried using oil additives, they lessened the oil usage, but they thickened the oil enough that I have a hard time getting car to start below 30F. Changed oil, not adding any additives, and it now starts right up at 30F, and below. The car sat for several years before I got it, and was hoping oil usage would go down as I ran it. WRONG, Engine has 255K miles on it, and I am guessing the rings/head are just worn out:crying

Luckily, Many OM617's were built, so currently looking for a lower mile donor:wink
 

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1982 240D, 1985 280E Euro, 1989 300TE, 1992 300D 2.5 Turbo, 1992 300SD
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My 78 300CD, burns about that same amount of oil 1Qrt/500miles , at interstate speeds 75/80 MPH. Less at the lower speeds that I usually drive. It is not leaking the oil, so has to be burning it. I have replaced my valve stem seals, and that has not improved the loss of oil. While replacing seals, valve stems seamed to be fairly loose. Have also tried using oil additives, they lessened the oil usage, but they thickened the oil enough that I have a hard time getting car to start below 30F. Changed oil, not adding any additives, and it now starts right up at 30F, and below. The car sat for several years before I got it, and was hoping oil usage would go down as I ran it. WRONG, Engine has 255K miles on it, and I am guessing the rings/head are just worn out:crying

Luckily, Many OM617's were built, so currently looking for a lower mile donor:wink

Yeah mine tends to burn more if I let some soot fly; I've also noticed quite a bit of smoke during take off and when driving at 70 and releasing the accelerator quick (like to catch the off ramp, or slow down during a brake check) it spews quite a bit a smoke too and both times blue. Maybe my car is in the same boat yours is :frown

To the OP, have a buddy flow behind you with a camera and see how much smoke you got coming out. And run some additives providing your location don't get too cold and doing a leak down test would definitely answer some questions :thumbsup:
 

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1985 300CD Turbo Diesel
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You might see how much blow by you have by removing the oil fill cap when it warm. If the stream looks like a train, the rings are probably worn.
I believe this has a lot to do with prior oil changes or lack thereof. My 85 300 CD uses about one half quart in 4000 miles and I have maintenance records way back to the early nineties. Even in cold weather there is very little smoke upon starting and no white smoke on acceleration. Virtually no blow by either.
 
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