OM603 location of coolant sending unit
 

Can somebody tell me the location of the coolant temp sending unit.
I'm having trouble with my temp gauge jumping and I want to replace it.
1987 300D #14 Head 270k miles.

Wrong
 

The coolant temp gauge sensor is B13, located on the left side of the engine below the intake manifold, forward of the IP and in between a couple of the glow plugs.

The sensor "forward of where lower radiator hose connects to engine" is the 50C temperature switch that operates the transmission vacuum solenoid.

Jeremy

... on the W124. The W126 doesn't have that system. On my car that temp sensor is used by the climate control system for overheat protection, which turns on the rad fans to high speed and also shuts off the AC progressively.

-Jason

OK, so which car does the OP have?

He's got the W124 based on his profile.
Gee, why is it again we ask for year and model of car???? ;)

Thanks
 

Thanks guys I edited my original post with the year make and model of my car, this jumping temp gauge is driving me nuts and unfortunately that gauge sender is in a really bad place, I was able to just barely get a finger in there to move the wire, to maybe give it a better connection if that's the problem. I'll take the car out for a ride later and see if it is still happening.

Let's slice W126s a little finer. 86-87 SDLs have the 50*C temp switch by the thermostat. 90-91 350SD/Ls don't. W140 Diesels don't.

Sixto
87 300D

I would probably remove the IM to pull that sender; others might depend upon a collection of adapters and u-joints to pull it with the IM in place.

If it isn't fixed by the wire jiggle, and odds are it won't, try running a separate ground wire "from" the frame back behind the instrument cluster "to" the back metal plate of the instrument cluster somewhere. Almost any screw location will work.
This has fixed many a persons jumping gauges.....