Check for low tires, dragging brakes (especially rears), low tranny juice. Most important, check for fuel leaks! Return lines, suction lines, fuel heater lines, etc can all dribble, and when they do, out goes the fuel. Lousy milage.

A slipping odometer can make it appear that you are getting poor milage too -- check against the milage posts on the highway sometime.

Change fuel suppliers, too -- diesel is highly variable, and if you got a tank of mostly #1 for winter floability reasons, milage will stink.

However, my brother routinely gets 28 on the highway in his SDL -- you are way low.

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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 will be making a 4 hour roundtrip tp Port St. Lucie tomorrow and I will post the results.

If all is well, I should be able to get 30mpg on the hwy.

What does a trap oxidizer look like?

Maybe turbodiesel can tell me whether or not it has been changed out.

Thanks

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Enough about me, how are you doing?

The trap oxidizer is a large (8"?) diameter aluminum sheetmetal covered thing betwee the exhaust manifold and the turbo, passenger side. It is replaced with a plain squarish pipe covered in aluminum foil looking insulation.

Quite obvious. Pics have been posted.

If you do have a trap on there, and it's plugged, you will also have lousy performance and possibly a "turbo" whistle from the blown seal on the exhaust manifold.

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!

My SDL gets between 22 and 25 mpg in mixed city/highway driving... depending on how much I let it idle. I've been letting it idle more recently because my alternator is dead, and I have yet to find enough time to replace it. Still, I filled up today with 19 gallons, at 425 miles on the clock.

ps fred,

According to your description, I have located the trad oxidizer and it definitely is not the 4" diameter one.

How do I go about getting it changed out? I have heard it is a recall issue?

What does it do?

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Enough about me, how are you doing?

It is a soot trap device. The soot is caught on ceramic rods, until it builds up enough to break loose, where it is then ground into tiny bits by the turbocharger.

It is a recall item, so the Mercedes-Benz dealer will replace it for you, free of charge. They will also inspect the turbocharger, and replace it if the turbine and/or compressor is damaged.

edit: "replacing" the trap oxidizer really means remove it, and replace it with a section of straight pipe... 5 more horsepower!

I looked up some more posts and the car has a stright pipe, not the big bloated canister.

I measured around and it is more like 7-8 inches in diameter, not 4" like someone had said earlier.

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Enough about me, how are you doing?

The new pipe is about 4 or 5 inches in diameter, not circumference. The old canister looked like a large coffee can, and is about 8 inches in diameter.

I can't tell from your posts which one you think you have. If you have the large one, you can get it changed out by the dealer for free.

Clogged traps have been known to damage the turbo, and possibly cause a warped head....damn aluminum heads...

Joe

E300D-95, 592 per tank

A brief update on my car' mileage.

After filling up at a truck stop last Saturday, I have altered my driving habits slightly and am happy to report that I have traveled 300 miles with 1/3 of a tank to go.

Will keep you all posted.

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Enough about me, how are you doing?

I try and not drag up old threads, I was searching around for something and this just jumped out at me, haveing maintained one for a good frind for the last 225K miles, I have to point out that the average fuel mileage through that entire time on the all aluminum fuel injected 4.1L V8 in an 87 Coupe DeVille is 22mpg city and 25-28 on the highway. The onboard computer is surprisingly accurate. It runs a quarter mile in 16.8 and has a comfortable cruising speed of about 130mph. It's still GM 80's plastic crap in a lot of ways, but the facts remain..

This is also on my mind as he just got rear-ended last night, the old car probibly would have made 300K otherwise. We've been doing a mechanical resto on an 86 4 door Sedan DeVille with a nice body and interior for him. It has a GM crate motor with very few miles on it, should last another 200K.

And everyone says the 4.1 was junk.. hmph..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

last tank 465 miles on 15 gal.. = 31mpg

never have achieved such mileage. i changed fuel sources a few tanks ago to getty. perhaps that is the reason

approx. 80/20 hwy/town driving.

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

Best I have ever seen on the 300D is a solid 30mpg over a 310 mile run north on I-55. Used just a hair over ten gallons. Normaly I'm pretty consistant at 25mpg, and fill up at 380miles or so(15 gallons +/-) due to a fuel gauge I don't trust, and a tank that I'm not sure of's capacity. Experimenting with keeping my foot out of it and my speed limited to 60mph or so, and thus far it's makeing little if any difference. Oh well..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

At what speeds due you normally drive and I hope you checked the next tank and if so what results did you get?

70-80 on the hwy and the previous tank with the same fuel source was 30mpg..
am closely monitoring the present tank.

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