Old Diesel Fuel Mileage question

1983, 240D automatic. Yes, it will go 75, 80 (at 80 I chicken out, it will go faster) though you won't win any races at the take off. MPG? Probably 17-22, avg 20, depending on the speed, of course.

hell at 80+ my 300SD gets about 25 MPG or better

the case, minus a few cans!

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

240d, small engine, has to work harder and the auto transmission don't help either... cp

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

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!

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.

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

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

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