Just a question of curiosity. I know my 240D burns a little oil because the oil level went down a bit over 2,000 miles, from almost at the "full" mark to a little below halfway between the marks on the dipstick. When I did an oil change (I did it early as I sort of considered the first change after I bought it a "breakin") only about 5 quarts came out (probably some left in engine but obviously it lost a little). But I never can see any smoke, other than for a tiny bit on startup on cold mornings. It stinks like heck (the exhaust system is in terrible shape) but I never see a hint of a puff from anywhere, the tailpipe or any of the holes that come before it. It doesn't really make a hill of beans difference, but my inquiring mind just wants to know. Maybe I'm just a little too bored as I wait for my parts to come in for the other car ...

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

And you have no Oil leaks?

Actually there is a thread somwhere where evidently some cars burn off down to about 1/2 low on the Dip Stick; but after that do not seem to burn any more.

Also if the Oil is being burned as Blow-by I would not expect it to smoke like liquid Oil that passes past the Piston Rings; because Blow-By is an easily burnable vapor.

It is also clear from other threads that Cars that may not burn any in normal traffic; but when people have gone on long trips where they spent time at highs speeds they were surprised how much oil the burned.

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84 300D, 82 Volvo 244Gl Diesel

All engines use a little oil; the question becomes "how much is normal" and "when does it become excessive?" Engines can also leak oil; you don't mention whether you see drips underneath. Because your car is a diesel, it's gonna smoke a little bit anyway, especially when it's cold, so you could be burning a little oil and not even realize it for the diesel smoke (if any). A quart in 2,000 miles is not anything I'd worry about, especially in a new-to-you car. It may simply need to be driven hard a few times to clean out the moving parts.

As a general rule (YMMV), I consider an engine to "use oil" if I have to add oil in between changes. My former '85 300D (230,000 miles) used very little (dino) oil -- never had to add any between changes. My '87 (150,000 miles) uses (dino) oil to the tune of a quart per thousand due to bad guides/seals -- that's why it's getting a new head. My '96 (270,000 miles) does not need (Mobil-1) oil added in the year and 8,000 miles between changes.

So I'd keep driving, keep an eye on the dip stick, and not worry yet.

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Thanks guys. Forgot to mention, rarely see oil spots on ground, but the oil pan and front of engine does have a lot of gooey oil on it ... probably accumulated over years. Occasionally I'll get a little drip but probably not losing a lot to leaks. I'm not real worried about the oil use ... I was just curious as to what makes it smoke or not smoke. Most people seem to have smoking in threads I've read on oil use ... that said a lot of them are burning a lot more than mine so maybe that's why.

Diesel911, sorry to be daft but I'm a little confused about what you said about blow-by ... I thought blow-by was just compression gasses escaping the cylinder ... does oil end up vaporized in it? Never really thought about that.

All in all the car starts and drives fine right now ... not planning on investing a lot more in it but as long as it wants to go I'll keep it going.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

yes, blow by is compression gasses passing the rings and the valve seals. any hot exhaust gasses passing this area will vaporize a small amount of oil and cause oil vapor to escape on the way to the intake path.

There is a lot of threads about folks complaining of the amount of Oil in their Air Filter Housings from Blow-by.
The hot gasses from the compressing passing by the oiled Cylinder Walls and Oiled Pistons vaporize the Oil as they go by.
I looked up Vapor and Vaporized and had used the word Vaporized because I do not know what other word to use. Perhaps what I mean does not match the definition of vaporized.

So I will invent a new term and call the Oil in the Blow-by "Oil Steam".
In any event the Oil Steam in the Blow-by that does not condense in that Air Filter Housing or the Crankcase Breather goes into the intake Manifold and is burned in the Combustion Chamber.
If you have a lot of Blow-by there is Oil in that and it is going to burn better than the Liquid Oil that gets past the rings because it is already in small particles to begin with.

About a month ago I tried to do something about containing my Blow-by issue and at the same time changed my Air Filter to a position where I hope it will not get contaminated by Blow-By.
Thumbnail of liquid Oil found in the U-Tube going down to the Turbo.

What I tried to do about it.
Washable Air Filter and Intake Mod , With Larger Breather
http://www.peachparts.com/shopforum/showthread.php?t=280376

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84 300D, 82 Volvo 244Gl Diesel

Some things I did not comment on. Sticky Piston Rings might allow more Oil up into the Cylinder where it would be burned. If you happen to have the Injectors or Glow Plugs out and have some time to let the Car sit you could try something like soaking the Pistons/Rings with Marvel Mystery Oil. It is cheap and appears to work if you have any sticky Rings.
You would need to do an Oil Change after the Soak.
Marvel MM oil results sticky rings
Original thread also has + response
http://www.peachparts.com/shopforum/showthread.php?t=258757&highlight=Marvel

If you are using synthetic Oil the above may not help.

Oil can get past Intake Valve Stem Seals during Idle on Turboed Engines and anytime the Engine is running on Non-turboed ones.

Then there is the obscure one. I believe it is 2 members have said the tiny little O-ring on the that seals the Push Rod in the Fuel Supply/Lift Pump went bad and they said the Lift Pump was sucking in some of the Oil that lubes the Cam of the Fuel Injection Pump and that it was mixing with the Fuel and injected and burned.

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84 300D, 82 Volvo 244Gl Diesel

Thanks. I knew of the oil-in-the-air-filter concern but never really thought about the vapor ending up burnt. It makes sense now. I know there's a million blow-by threads and I've read a lot of them, I just always thought about it in terms of stuff blowing out, and the wear it indicated, not anything going back in.
The oil doesn't (yet) get as far as the filter element itself, although last time I checked there was some oil film in the intake pipe ... doesn't look like a quite have a puddle like you had, yikes.
I'll check out the marvel mystery oil thread, too. Interesting about the lift pump ... never would have thought of that.

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

When I change my oil, I put in exactly 2 gallons and go right up to the fill mark.

I never bothered to try measuring out 1.9 gallons.

After about 2 or 3,000 miles the dip stick will read at exactly the halfway point and never drop below it.

I'm guessing it is getting burned, but smoke and leaks all look ok.

As long as you're not using a ton of oil I wouldn't worry. I've never had to add more oil between oil changes, I would say that's a good metric to go by.

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-Typos courtesy of my mobile phone.

The Lift Pump O-ring issue surprised me also. What I have seen many, many times is that when that O-ring goes bad the Fuel goes the other way and gets into an contaminates your Crank Case Oil.
The Symptom is you have a rising Oil Level; and if enough Fuel gets in your Oil will have a faint Diesel smell.
So I was surprised and skeptical concerning the Oil going the other way and getting into the Fuel but apparently it can.

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84 300D, 82 Volvo 244Gl Diesel

I dunno, I think oil consumption is overrated as a metric for how worn an engine is. But that's probably because I'm running a relatively fresh engine (12 seconds with the blow-by tube plugged) that burns a quart every 900 miles for some reason.

A quart in 2,000 is an awesome oil-use level.

As for smoke, well, these cars are made to burn oil. I doubt you'd see much visible smoke if you poured a liter right into your fuel tank and burned it with the diesel over the next 300 miles.

Finally ... you mention it stinks. If you burn biodiesel in it, it will quit stinking and start smelling more like a hot barbecue grill. It's more expensive but if you've got exhaust entering the cabin, it'll pay dividends in health and comfort, at least until you can get the pipes fixed.

cheers!

--Finn

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Finn John -- Albany, Ore.
www.offbeatoregon.com
76 Merc 300D, sky-blue, *86k, for driving
84 Jaguar XJ6, black, 245k, for restoring someday
71 Merc 408, 2.3 petrol 4, Avon caravan conversion (UK), RHD