hi I have a 1982 Mercedes 300D Turbo Diesel 4 door sedan. The car has a 1985 turbo diesel engine in her, with 50,000 miles. I changed the oil 2000 miles ago and it still doesnt need any oil, it's unbelivable. Well my question is how many MPG am I supposed to get? From full to half tank i get about 150 miles. Once I reach like 250 miles im nearing empty, I dont know why. These cars are supposed to go 600 or more miles in a tank full. Is there any reason this could be happening. I know the alignment is real bad and I need new tires that I will be getting later in the summer. But How many MPG can I really lose from that? it pulls to the right. The trunk smells like diesel could most of the diesel be leaking there or something. I know I have to replace the rubber thing in the gas casket, because its puntured, thats why diesel is leaking into the trunk but thats only when the diesel oil reaches to the casket, and im guess that happens when the tank is full, how much could it leak from there? Since the car has a 1985 engine, does that mean the car has a trap oxidezer, what is that a special air filter or something, and how can I tell if I have it. My tranny is rebuild, and wondering how is it supposed to feel? Sometimes it is as smooth as it can be and other times, you can feel 2nd gear kick. Mostly when the engine is cold or im pushing the pedal lightly, depending on how I push the pedal.

I have a 1983 300D turbodiesel. Your tanny is perfectly fine. When my engine is cold, and it shifts the sequence for the first time all the shifts are delayed and abrupt. When on a long freeway ride, and then when you slow down and go through the shifts again youll notice they'll be silky smooth.
I get a low of 25 high of 31mpg. The 25 was at a non-stop avg. of 78mph. The 31 was a mix of city-light highway.
My fuel light starts glowing after 400 miles, it glows when there is still 6 gallons left. You are clearly losing fuel, when you top it off its leaking somewhere, dose the fuel gauge move quickly from full after only a very short time?

I have an 81 sd with 70,000 miles on a replacement engine it used 8 oz of oil in 3000 miles (better than most gas cars I've owned ) I run 32 psi front tires and 34 rear (Michilem) rainforce)I replaced front brake calipiers and all hoses and all belts. I had transmission backflushed and differential drained and refilled,replaced glowplugs and fan clucth. We live in Costal Mts. of Oregon so most of our driving is on two lane roads with lots of curves and grades.
With carefull checking I am getting 28.5 mpg. I would call myself and my wife very conservative drivers ,well I do push it hard enough on the rare straight strecth to feel that wonderfull turbo come to life....(lot of words to tell you I get 28.5)
William Rogers

I owned an 83 300D for over 10 years and just passed it on to my daughter with 160K on the odometer. I kept very good fuel records and it averaged 26.7 mpg over an extended period of ownership.

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99 E300 133K
98 ML320 99K
87 Saab 900 Turbo Conv 123K

I recently got 27 mpg. This was a split of 70/30 highway/around town driving, and I use Mobil diesel. My tank was just a little under the half tank mark and the trip odometer was reading 289.8 miles, she took in 10.8 gals. That works out to exactly 26.833333333 mpg. So I rounded up to say I get 27. Not too shabby for a car that weights a little over 4,000 lbs.
I say Mobil because where you buy your diesel is very important. You should buy diesel from a place that only sells to a few customers, because that means that diesel fuel is just sitting there. I buy from a station that see alot of business from truckers. This way I know that the diesel they sell is "fresh". My mechanic said that you should never try to save a few pennies by buying an off brand diesel. It will catch up with you. You should always run fresh clean diesel in your car, and check the pre-filter.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

W107, first, welcome to the coolest site on the internet! Your mileage sounds low, and this is from someone who was averaging a bit under 20 mpg over 16 months or so. Mostly short trips. Highway always is over 25 mpg, worst city mpg was 14.5 with a bad thermostat that wouldn't let the car get over 60 deg C.

I would check your brake rotors after a long drive. Is one of the fronts hotter than the other? This would indicate that one of the brakes is constantly rubbing, in other words, never releasing fully. Also make sure that the rears are not hotter than the fronts; this would indicate that the parking brake is not releasing. Check your tire pressures. I run 28/30 f/r. Good luck, and welcome.

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

I was just commenting this morning to my wife how great fuel mileage our '87 300D turbo is getting.I have been watching this scrupulously for 7 months.I recently did the Lubromoly "diesel purge".Great improvement since then.Also i have heard warmer weather improves diesel mileage as they are not blending it with kero.As of today my car has gone 157 miles on 1/4 tank.That's roughly 4.5 gals.No i didn't make a mistake somewhere.I fill it up..I keep track of the mileage.This is what it gets.Oh by the way...that is all country/around-town driving.No open road 70mph miles either.I am amazed and thrilled to have such a powerful,economical,luxurious,SAFE,vehicle to haul my ugly carcass around.She just turned 116k so I know I have many more years of enjoyment....Try the diesel purge after you get your problem fixed.I too think you have a leak somewhere.Check your return lines(braided on the injectors).
They can seep and the fuel evaporates on the hot engine.And check both lines to/from the tank.Good luck.

What's up Rick????

Thanks for your help guys bout my miles per gallon problem. Im really wondering, my car really pulls to the right bad, cause the alignment is terrible, how much diesel could I be wasting. Could I lose 200 miles of fuel from the wheels being that way. I do start my car, and turn off the car alot. Because I do pizza delivries with this car, could that also kill the fuel fast. How big is the Tank? 21 gallons? usually the light will go on, and when I fill the tank it fills 14 gallons how much fuel do I have left in the car? I just found also that my air filter is really dirty and im gonna buy a new one, could that also kill fuel mileage. Im thinking of buying the K&N filter it uses cotton instead of paper, is it worth the money to buy that.

Greetings,

If you deliver pizza with this diesel, and only away from the car for a few minutes, I'd leave it running. I don't think it would drink that much fuel restarting it each time, but if the neighborhood seems safe let her run, or get a second key and lock it while it's running and you're at the door giving pizza and collecting the cash. Like others have mentioned, there are several things causing you to lose fuel, from a leak in the tank seal to lines to improperly adjusted IP or valves perhaps to bleed lines and return line. Just need to check out from the tank forward and fix what's leaking or seeping and your mileage should come up some. I do a 40 mile stretch one way to work each morning, they call it the hell run because it's nothing but hills and dips and curves galore, but I still maintain about 27 mpg with such terrain and traveling at 65mph most of the time. Gotta love the country to travel this road, or don't want to take the alternate route which is 20 miles longer.


Charles

W107BenzW123MB,

If you're on empty when you fill up, and the tank only holds 14 gallons, I think that's most of your problem. These tanks hold 18 gallons, so you've got about 4 more gallons to go!

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Matt
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1995 E300 Diesel (Die Blau Frau)

I too have a 1982 300D Turbo which I receintly purchased. I am in the low 20's for milage and am working on possible milage boosts. In reference to your trunk smelling like diesel, I had the same problem. I opened the trunk and removed the four bolts fastening the rear cover, the one covering the back side of the trunk. I then pulled out the plastic liner that covers the inside of the right rear fender. This having been done you can clearly see the back side of the fuel compartment and the overflow line for it. I found on mine that the plastic (black) line running from the overflow nipple in the bottom of the fuel compartment had shrunk and pulled away form the nipple. I then bought a piece of tubing which would fit over the black plastic line and attached it with a clamp. The other end of this new line fit snuggly over the overflow tube nipple. Now when I fill my tank if it over flows at all it actually goes overboard instead of in the trunk. I hope this helps you out.

Rick

Icesailor......aside from the topic...I was wondering if you iceboat from your sign???? I do here in N.J. on the Barnegat Bay and Lake Hopatcong.....fastest way to from 0-70 and NO SPEEDING TICKETS!!

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Dale, R129
W202

Dale,
Yes I do in upstate N.Y. As I tell everyone, it is the most fun I have ever had with my pants still on.

Hi Rick! Where in N.Y. do you sail? I have a Viking which was built locally here in Island Heights. It is VERY close looking to a Nite. Down here on the Bay, we have PLENTY of DN's, a couple of Nites and Skimmers. There are about 10 Vikings that sail. I built a hollow spruce plank four winters ago and have only used it once. About 12 years ago we held the DN Worlds on Barnegat Bay. Poland won that year, and they sold all their boats here before they left. I took some really neat pictures of some A-Class Stern Steerers which I submittes to several sailing publications. I even sent one to Yankee Magazine for a winter cover..but no luck. It's a great sport, but as you know is soooooooo weather dependent, it can become frustrating.

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Dale, R129
W202

Dale,
I sail on the finger lakes. I have not sailed in a couple years for weather reasons as well as others. I hope to this year though. Yes this is frustrating due to weather constraints but it makes the good runs sooooo much more memorable. I have DN's as our ice is never open enough to afford a ride in anything larger. I have enough room to get a larger one running but then not enough to shut it down. I wanted to build a sheeter but have not. If I figure out where I can run one I will build one, 150 mph....now that would be a ride! An old friend of mine wanted me to go to Barnegat Bay to sail once. We were going to both go down but the plans went arye. So anyway....ice boats and Mercedes Benz's.....life is sure good...no?

Rick