Reply from VDO - MB fuel gauges

[Zeus]

I'm convinced that there is a defect in some MB fuel gauges. In all three MBs I've owned - 1971 250, 1977 280E, 1989 300E - the fuel gauge has had the exact same problem. It shows full to half fine but from half to empty, the gauge dances around. The low fuel indicator light is constant and works well (that, combined with my trip meter is how I measure my fuel consumption). I find it odd that all three cars from over 3 decades have the identical problem!

I've checked the sending units in the tank, with advice from this forum, and they've all been squeaky-clean. The floats slide perfectly. In one case (the 280E) I replaced the sending unit and still had the problem.

I recently contacted VDO with a description of the problem and here's the reply -

Hello Chris ,
we here are not aware of any problem with the MB fuel gauge . However if you need service to be done , please check with our service centers here :

http://www.vdona.com/Tech%20Support/repairpage.htm

these companies may find something in you cluster .

Mit freundlichem Gruß/Kind regards

Klaus P. Bornhaeuser
Manager Technical Support
Siemens VDO Automotive AG
188 Brooke Road
Winchester,VA.22603
Tel. 540 678-XXXX

I'm still not convinced. A thread in this forum mentions that re-soldering the cold solder joints in the back of the gauge in the instrument cluster can fix the problem. That will be my next step.

Still, I remain convinced that these gauges have an inherent fault. I've never had a problem yet with the oil, tach, clock, speedo, etc. Even the "economy" gauge works well. Too many people seem to have this same problem..there must be something to it. Anyway, I'll see how the soldering goes...