Has Mercedes ever acknowledged the horrendous design defect in the 6 cylinder diesel engine used in the 1991-95 350 models?


Asked by Oct 16, 2007 at 11:15 AM about the 1991 Mercedes-Benz 350-Class 4 Dr 350SDL Turbodiesel Sedan

Question type: General

We were Mercedes diesel buyers from our 1976 240D right throught our calamitous involvement with the 1991 350SDL.  The car was a masterpiece of engineering and aesthetic beauty.  It was a 3,800 lb. car powered by a 148 HP turbo-charged diesel, and it really performed superbly.  The finish of the interior reflected the kind of class for which MB had come to be  known.  The 126 body was as handsome as one could ever want.  BUT, the 6-cylinder diesel engine had gone into production without adequate testing and the failure rate from piston rod bending and ovalling of the cylinders caused the engine to consume itself over time and to fail around 80-100,000 miles.  MB, to its discredit, affected to be unaware of the problem and used the tactic of "walting the customer" with flimsy and vague excuses until the car was out of warranty.  As the oil consumption soared and the car began emitting huge plumes of heavy smoke and particulate matter, Mercedes would say that the car was "getting old" and needed a new $14,000 egnine.  A Mercedes diesel was "old" when 7 or 8 years on the road with fewer than 100,000 miles on  it?  This was not exactly the tone of MB's advertising used in the 1970's and 80's, then they were a "car engineered like no other".

As Mercedes began cheapening tiself and throwing its reputaiton into the gutter, the swagger of the MB USA field represnetatives got more haughty.  We were told that MB's helping us (a 7 car buyer) "could get around" so they declined any assistance.  We got an insolent letter form a woman named 'Lisa" at MB USA thanking us for having the problem with our car so that MB could ahve the opportunity of stating its corproate position on the 350SD and SDL engine.  Needless to say, we will never buy another Mercedes.  They're homely today anyhow and made largely of plastic.  What a shame.

The sad fate of Mercedes Benz does not detract from the wonder of the cars they once built.  Those cars, and the Daimler Benz company that built them, now belong to the ages.

Mercedes Benz and its wretched end remind me of the fate of Titanic.  In its day, each of them was one of the greatest things in the world.  But each made a mistake, fell, and neither ever got up again.  Glorious though each once wazs, you would want to be neither with Titanic nor Merceds Benz today.

Richard E. Savoy
Salem, MA

1 Answer


I don't believe they have ever fixed it. I don't see too many newer MB diesels on the road, either. I recently had the pleasure of meeting a German gentleman here on vacation, who stayed with my family for a few days. He certainly had no love for MB as he remembered vacationing in Bavaria in a pre-turbo MB Diesel as a child, when he would get out and bike ahead to the next stop while dad, mom, and sis puttered along pulling a small trailer and a boat on top of the car at 48 HP.

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