It seems that my 500 Sel has a extremely erratic fuel gauge - it either shows too much, too little or simple jumps from one point to another in a strage fashion...

Since I had this happen with my other 300 TD Mercedes I wonder how common is this fault on '80 Mercedes-Benzes. Didi it happen to you also? If yes, how can it be fixed?

'92 500 SL fuel gauge is steady as a rock.

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roadkingmike@aol.com
Coast Aero Support Services, LLC
'92 MB 500 SL
'01 BMW 525i Sport
'98 Harley Davidson RoadKing
'74 BMW 3.0 CSi - Gone to a good home

Mines bouncier than a Vista Cruiser with origional shocks. But I watch my trip meter, so I have two sources to guage my reserve.

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1989 300E 144K

Mine is jumpy as hell. Plus it goes from half to reserve in the blink of an eye then it stays there for weeks!!

It's not your fuel gauge, it's your fuel sending unit. Replace it -- they're not that expensive -- and all will be OK fine!

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'01 SLK320, '79 450SL & '01 C320 -- What? 3 Mercedes? I am DEFINITELY crazy!!!

So, is this an electronic problem or a mechanical one. I was imagining a sticky float or some such thing.

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

These "jumpy" problems are invariably the float in the tank.

My $0.02: Never let your SL go down further than half a tank, for the following reasons:

1. I think that there's a lot of evidence that running a tank very low or dry will contiribute to the demise of the fuel pumps. These pumps (like all modern electric fuel pumps) use fuel for cooling and will overheat and be damaged if run dry. I personally had two $300 repairs on GM cars involving this; one empty tank = 1 new fuel pump. There simply is no reason to even risk running dry.


2. $35 to fill up your tank vs $70 could be the difference between being annoyed and being laid up/dead after a heart attack.

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

The fuel sender is actually a cylinder-shaped cartridge that screws into the top of the fuel tank. The float is inside the cylinder. This unit cannot be disassembled for repair -- it's a sealed unit. Nor would you be able to fix it once you got it apart.

So the answer to your question is "yes." It's an electromechanical problem.

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'01 SLK320, '79 450SL & '01 C320 -- What? 3 Mercedes? I am DEFINITELY crazy!!!

So all you can do when it goes "crazy" is to replace it?

I thought these cars are made to be fixed not replaced