temp gauge sending unit 72 220d
 

where is sending unit,is it on head above glow plugs?i know it is mechanical,not really sure what that means ,can i just change out sending unit or is it all one hard wire to gauge?

anyone out there have any info on this

I do not have a 72 220d. The 84 190D had the same problem with a non functional temp gauge. I am telling you what I did and it may or may not apply to the 220d. My 190D temp sensor is in the engine block where the glow plugs are. A ONE pin sensor with a wire to it. I remove the connector, shorted the connector to ground and the gauge shot up to red. It shows the gauge and the wiring from the connector to the gauge is good. I replaced the sensor and all is well.

Hope this help.

On my 70 it is 1 wire from the instrument cluster to the engine I think.
You should be able to follow that wire to the engine.

Not sure, but I think on a 220D it may be a metal tube rather than a wire.

Yes its a metal tube filled with ether, as it gets hot the ether expands and causes the gauge to rise.