My 85 230 quit running, I just installed a new fuel pump, it fired right up several times but when I came back 10 minutes later I got the same thing as was happening before. It cranks like a champ, but absolutely no hint of firing, and no smell of gas at the exhaust pipe. I assume that my original pump, and now this one are fouled or clogged by gunk from the tank.
Soooo, it is easy enough just drain out the tank, but will that take all or enough gunk out with it (the tank is full, the last thing I did before I had the problem was fill it up. ) ? will it be enough or is there more that i can do with the tank still in the car? If the tank has to come out how do I do it and then what? thanks, Andy

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andy t
'78 300d
'95 volvo 850, wagon
'86 300sdl - engine out, maybe I'll have it rolling by June

whole bunch o' bicycles

Your first line of defense against crud in the tank cloging your car should be the fuel filters, of which I think there are two.

Check to see of your filters are clogged.

There might be a tank strainer on MB gas engine cars as there is on Diesels. There should be a clear plastic filter on the gas line, and probably some sort of screen right up near the injectors.

I'd check this first. Messing with tanks is a pain.

On three occasions, I filled up my tank and discovered that I had purchased a tankful of water. This is a good reason not to buy gas or Diesel when it's raining or flooding, but it can happen anytime,

There is a drain on your tank. Check a shop manual , such as Haynes for the exact location if you don't spot it.

If there is water in the tank, it will sink to the bottom and will be easily distinguished from gasoline.

Drain the tank until all the water has exited and all that is coing out is gasoline.


Gas dryer (basically methol alcohol) will help to get rid of small amounts of water in the system.

I am not sure how one cleans crud from a tank, but I think it's as easy to do on the car as off, except for towing the car.

Cleaning a gastank is a rather specialized thing. Mostly small amounts of contaminants are removed with filters, and water is just drained off.

I would say that the most likely thing is that you have a tank full of water (a Diesel hose won't fit in your tank without your being aware of it.)

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Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)

I have heard of shops that actually perform this service (flushing/cleaning tanks).

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'86 420SE Euro
904 Midnight Blue, Gray Velour
Dad bought it new, now I own it.

"A Mercedes-Benz is like a fine wine, it only gets better with age."

The only way to really get the tank clean if it has a lot of crud build-up is to take the tank off the car. You'll need to wash it out with gasoline and shake it to get the junk to come loose from the bottom of the tank. Then turn the tank upside down and pour out the bad stuff. Repeat until no more junk comes out. Pretty basic fix, but it works.