Old Diesel Fuel Mileage question

All -
I have a '74 Automatic 240D.
Don't even say (or write) it. I know. . .
I currently run about 18 MPG at highway speeds (70 - 75 MPH - yes it DOES go
that fast, but it sounds similar to a window seat next to a Turbo-Prop Saab Airplane engine).
Around town, I seem to manage an average of 20 MPG.
The Owner's Manual doesn't clearly state anything on Fuel Mileage, except that "It can vary".
Anyone have any comparisons/correlations?
Thanks in advance,
- Bill Schmidt
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faster) though you won't win any races at the take off. MPG? Probably 17-22, avg 20, depending on the speed, of course.
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hell at 80+ my 300SD <82> gets about 25 MPG or better
the case, minus a few cans!
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On Sat, 02 Apr 2005 19:51:59 -0500, wrote:

1981 300 turbodiesel -yeah, it's an auto (I think all of the North American 300s were auto - true?) I get 25-27 mpg, almost regardless of what type of driving I'm doing. The numbers you guys are getting for the 240s are kind of startling. Given the very similar bodies, I just always assumed the 300s guzzled a bit more than the 240s.
Not to blow the topic out of the water, but it might be interesting to poll 300 turbo/non-turbo owners as well. I just always assumed my little brothers were a bit thriftier at the pump. Bizarre.
Conrad
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240d, small engine, has to work harder and the auto transmission don't help either... cp
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Very true, CP -
Not to mention that in order to keep this vehicle at 75 or 80 MPH, one needs to almost literally 'floorboard" the accelerator - about 3 MM or so off the floor. I'm sure that this contributes to the somewhat low MPG. Also, I'd wager that a differently-geared transmission would help...
Thanks for the input, everyone!
- Bill

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Be sure the air filter is clean; don't overload the engine - its overloaded if your car is laying down a cloud of black smoke (unburned fuel). The engine simply can't burn all the fuel being injected; it's at its maximum full load speed. PERIOD!
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Thanks for your input, T.G. - as always. No Mosquito Bombs behind me, just that loud, old 4-cyl. Diesel "Dynamo" sound around 75 MPH... "Waaa-uuuum, Waaaa-uuuuum" . . .
Interesting that you bring up clean air filters. Mine's an oil bath, but my Mechanic is absolutely convinced that the Diaphragm in the Injection Pump is what is causing my Oil Consumption problem - about 1 qt every 300 Highway miles. He (Franz the Mechanic) claims that my original Injection Pump Diaphragm is allowing engine oil to pass through it, and end up either being burnt or in the Air Cleaner assembly, via the breather line. He said in his 30 years of Mercedes work he's only replaced one on an old engine (actually, I believe he said the other one was a 220) but it showed the same symptom, and replacing the Pump's Diaphragm cured it.
I offered that in my own experience, a leaky diaphragm can almost always lead to surprises. It took him a minute but he finally got it.
Any thoughts/comments (on the Injection Pump Diaphragm theory, that is)?
Thanks in advance,
- Bill

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I know it's a different model, but seemed relevant.
95 E300 (diesel), auto, with 210k miles on it. I average 30 to 35 mpg in fall, winter, spring at highway speed averages of 70-80 and moderate in- town driving. Summer (due to AC) drops average to 29-32 mpg.
Anybody use Diesel additives? I usually throw in some Howes Diesel treat, seems to keep the smoke down and gives me a quieter warmup period.
--
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I use only Lubro-Moly Diesel Fuel Additives. "Diesel Purge" on occasion, and "Diesel Hi-Test" every other tank or so - with much success.
- Bill

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'81 300TD Turbo. Get about 30mpg average.

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