I am a new W124 '95 E300 Diesel owner. Upon getting it home, I looked under the hood to check it out and I noticed a very faint diesel smell near the fuel filter housing. The car drove fine on the way to the house and nothing seems to be leaking. It looks like some residue might have simply been left from a recent fuel filter change which I am assuming the selling dealer may have done for me prior to shipping the car. Anyway, i saw this screw which says "stop" on top of the fuel filter housing. It has an arrow shown on it signifying that turning it clockwise will put it to "stop". Out of curiousity, I turned it to see if it might be the cause of the odor and it was loose, so i tightened it. I then came back to my desk and thought "hey, maybe I shouldn't have done that...."

I haven't tried to start the car, but I'm guessing if I do, it probably won't run as I am now thinking the stop screw it interrupts fuel flow to aid in filter changes and/or to manually kill the engine. Can anyone confirm if that is the case?

So I guess i'm going back out to loosen it a few turns. Should I turn it counterclockwise any particular number of revolutions as a recommendation or is it unimportant?

Thanks much.

Turn the valve counter clockwise to open it. Diesel smell/leaks may be a bad o-ring on the valve body or the prefilter o-ring or any one of the plastic fuel pipes. Until last month, my 95 e300d with 182,000 leaked fuel at the shut off valve, one of the plastic pipes and fuel pump delivery valve seals. All dry now. I also replaced my old fuel supply hose too. No diesel smell after I park it in my garage. I'm a huge diesel fan...especially when I can't smell it.

I suggest using the search function and read every single thread that mentions 95 e300d. You'll catch the bug like the rest of us.

There are Mercedes diesel gods on this forum. You wont be sorry.

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900