I have a 1976 240D. I travel 42 miles a day round trip to work. A little over half of my daily commute I am traveling the highway and speeds form 65 to 70 miles per hour. My fuel mileage averages around 23.5 to 24.5 MPG. Does this sound about right? I also have the AC on which is surprisingly arctic cold. My engine burns no oil in between 3000 mile oil changes.

Yup, sounds about right.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

The average fuel economy back them was about 15 mpg, so while 24 may not sound great by today's standards, it was well above average.

This publication gives the fuel economy as 24/31.
https://afdc.energy.gov/files/pdfs/1975_feg.pdf
But keep in mind the test driving cycle back them was rather leisurely and didn't include A/C. So real world economies are always going to be less than the published values. As an aside, the testing has improved, so I think modern economy ratings are much more realistic.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

The AC on those was very cold but the York compressor uses a lot of power.

Confirm that your odometer is accurate.

My 1976 240D 4spd manual would get 30 MPG in top tube on pure highway driving. With AC on, combined city/highway and an automatic? your MPG is in range.

They are nice road cars.

Good luck, keep that oil changed!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

To me it seems a little low. My long term mileage in the turbo cars is 28-32 MPG, logged. My 240 never got the same long term long trip use, but even running on the highway seems to yield the same or lower results than the 300 cars. I think it’s because of how strained these engines are. My 240d is a joy to drive <55. Once you’re on a 55 or higher road, it will indeed handle it, but it’s not as happy.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

My 240 D is an automatic.

Not bad with the air on for an automatic. Your rear end ratio is higher than any of the 300ds and that hurts a little. Plus they did not have a lock up transmission.

Confirm that your odometer is accurate, they slip as they age and record less miles than covered. Oversize diameter tires cause the same issue. Using an interstate go ten miles by milepost and see what the odometer records to the tenth of a mile.

If it records less your getting less calculated MPG.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I hit 30 mpg on the highway with a stuck brake caliper, worn out brearing grease etc. 4 speed manual though.

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html

Thanks everyone. I will verify the Odometer.

We get 21-23 city /27-29 hwy out of our 1981 240D, it has a stick but I don't know if that makes a difference at highway speeds. Generally we stick to 65mph or so on the highway and the AC is rarely turned off.

There are some folks that have some pretty big MPG claims with these cars, I'm not one of them. And yes, our Odo is correct.

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1981 240D Four on the floor, Orient Red over Parchment, bought with 154,000 but it's a daily driver and up to 180,000 miles, mostly original paint and all original interior.

The automatic will get 2 to 4 mpg less than a stick in my experience. Yours sounds very good.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

my fuel economy in a 83 240D automatic ,no A/C:

80% highway @ 65
20% state routes

26 MPG consistent

yours sounds about right

Yes, this sound about right to me too .

How about a picture or three of your car ? .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better