Will the fuel sending unit off a w126 gasser fit/work for a w123 300d sedan?
The fuel guage looks to be acting up on the 79 300d....shows a quarter tank and then all of a sudden the red light comes on showing low fuel. I was hoping to swap the sending unit out of one of my 88 420 sel parts cars.Thanks.

Pretty sure a 126 unit won't work in a 123 unit. But I think a 123 gas unit will work in a 123 diesel just as a 126 diesel and gas unit is interchangeable.

Let me rephrase that, it will probably work, it just won't read empty when empty or it will read empty when there is still fuel in there.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

I've been wondering about this sort of question also, but I would want to go from a '82 300sd into a '83 300d? It sounds like that won't work.....

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'83 300D (220000 miles and counting)

Answered my own question...
'83 300d Fast lane part # W0133-1604571
'82 300sd Fast lane part # W0133-1611374

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'83 300D (220000 miles and counting)