Is there any reasonable way to increase the fuel economy on an 84 300D without harming the engine or any subcomponents? I would be willing to greatly increase fuel economy even at the cost of some engine power.

How much do these diesel engines depend on fuel to cool them?

Thanks for any ideas,
Aaron
(proud new owner of a 300D)

Aaron - how many miles on your 300?


keep your filters clean and your fuel coming from a 'good' source. try different sources in your area and keep a record of the economy to determine which one is best.
higher ambient temps are also a help.

another thing is you can try to keep the car light - as in not use the trunk as your garden shed , lol

i would say that the engine does not use fuel to cool itself , not one bit.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

It's got around 250,000 miles on it. No blowby, new fuel distro, new fuel lines, new fuel filter.

So there isn't some screw I can turn to reduce the amount of fuel getting squirted in there? Or there is, but there are negative effects besides power loss?

I just couldn't hold out for a decent 190D 2.5 or Turbo with better fuel economy, plus I love the styling of the w123 much more. I guess we'll see what kind of mileage I get outta this car.

one fairly easy way(if, you're handy with a wrench) is to drop in a rear end from a 1985 300D . or a wagon , etc:-
The 2.xx ratio will give you not only a higher cruise speed, but also a good 2 mpg gain. Plus, the car wont be so 'buzzy' at highway speeds

It really is a bloodless bolt-in, 1 hr at most.

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1982 300SD (214 k, excellent shape) kidmobile running mostly biodiesel, gets 31 mpg hwy with 2.82 rear from a euro 500SEL



1976 115 body 240D 4-speed (traded for Jeep parts) - Engine lives on in my CJ7

think you could turn down the alda a bit but not sure it would help.

how about the air filter? it could be really dirty which could affect your fuel economy..
would check and replace if necessary.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

Three things:

Good alignment -- too much or too little toe will kill you.

Raise tire pressures to 32 psi all round, use only good radial tires of the correct size (or a bit bigger).

Make sure the brakes release properly all round, espcially the rears, as you won't get any "feel" if they do, only less performance. Jerky stops are a sign you have stuck pistons in at least one caliper.

And, most importantly, drive like an old lady. Diesel use much more fuel when driven hard -- gentle acceleration and long coasting stops save brakes and fuel. Keep it under 75, perferably under 70 on the highway, too -- they love to go faster, but use significantly more fuel if you do.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I think another way of saying what the accumulation of posts so far is..... try to keep the car as efficient as you can . The MB diesel is already amazingly efficient... if you just learn to practice the kinds of things mentioned......that is the best way to get good mileage and have the engine last as long as possible....
Some claim that using Synthetic oil will help on the mileage.. and it may ... but too often using it is used more as an excuse not to change oil as often.... and I am a believer in DRAINING the stuff out of the system.... so I use Delo400 and change often...

Follow the good suggestions above, keep a clean air filter in the car, and realize that the most important factors in fuel mileage are weight and driving style.

Good luck,