jumping fuel gauge - W126

[86560SEL]

Very common MB problem it seems (despite my 190D or 380SE not having the problem), but I have given my mother my 88 300SEL and it has this problem. I was told it was probably the sending unit. I was told it could be cleaned. I called a local MB repair shop and he said new ones are like $292 (Fastlane has them for like $213) or someone said I could get a used one for $150 or so (but what are the chances of it going out soon too?). He said labor would be about $30, which sounds really good to me... if I only had the unit now.

What is going to be the easiest and cheapest way out here?

[tinypanzer]

How bad is it jumping? Does it do it only when the radio is on? I ask because in my car, the voltage being dumped to the chassis back there, or just the mechanical vibration tends to make the gauge jump around, but not too muc and mostly when you're getting low on fuel. It will actually strobe the low fuel light to the beat!

[tbomachines]

If it is anything like the diesels, it is a piece of cake DIY to take out and clean off. In the very least some security knowing you're not throwing money at the thing. Sounds exactly like bad contacts in the fuel sender if you ever had gunk in the tank.

[mak]

Suggest remove the sender unit from the tank , clean the very delicate resistance wires running the length of the unit ,and all should be normal.

i did replace mine with a new one ,cleaned out the old one and it starting working normally. The problem is caused by the corrosive water content in the fuel.