Hey all,
Just following up on this earlier issue- for those who may suffer something similar.

The ENGINE TEMP SENSOR aka FAN CLUTCH SWITCH aka ENGINE TEMP CONTROL was bad after all. It is a simple switch that is screwed into the water neck that activates the magnetic fan clutch when the engine temp reaches 100 degrees C. In later models it activates the fan clutch at higher temps and has a green cap.

NOTE- my 87 euro 190d with 2.0L diesel has a magnetic clutch like on the early gasoline models. In talking with SEVERAL shops/techs/parts suppliers I found that MB used several different configurations to cool 190s (diesel and gas) depending on what they were destined to be used for, and where- so this results in the confusion.

I went to my dealer and several parts suppliers, and we found that even though MY temp switch had OEM PART# 006-545-4224 on the body (red plastic top with 3 male terminals on top- configured as 2 on one side of a plastic seperator/blade and one on the other with a brass body), THE CROSS REFERENCE AT THE DEALER AND MOST PARTS SUPPLIERS WAS WRONG. What I was often handed was a similar switch with only ONE male terminal on top, or told that the "factory air" brand's number was a hi-pressure cut-out switch for ac's.

Community Auto Parts here in Chicago WAS finally able to get the switch, but the oem part number is written on the side of the box. SO for the benefit of anyone else who might have this problem, I am listing the manufacturer's "Nr." to help other forum members locate this rare switch.

It is a BEHR Nr. 817505 and is listed as a "TEMPERATURE SWITCH."
You might want to pick one up if your's hasn't been replaced to prevent overheating this summer.
Cheers- John