Help- 87 190d overheating problem...
 

Hey everybody,
Drove the 190d (87 euro 2.0L 4spd) in heavy traffic and watched the needle rise to about the 110-115 degree area of my temp guage this weekend. The auxillary cooling fan (I have just one on the driver's side) never came on. I also never heard any fan noise from under the hood either. I eventually avoided overheating by running the heater...

I am nearly certain I have the "Magnetic Fan Clutch" on my model- the fan can be spun freely in either direction by hand when the car is running at idle and normal running temp.

Is there any way to TEST this fan clutch?

Also- is there some sort of temp sensor that may have caused these fans NOT to come on? If so- where is it, and is there a way to test it?

Please post or email- thanks in advance- John

Any suggestions?

First, I believe the diesel has a visco clutch (at least the 2.5L I saw Saturday does). No doubt yours is covered with sticky black oil and is non-functional.

Second, check the fuse for the aux fan, they fatigue and break. Also check the fan by wiring direct to the battery, they do sometimes fail (although not often).

Electric fan is switched on by a temp sensor on the engine, I believe, just like the older 61x engines. Aux fan should also run in slow speed when the AC is on via a pressure switch on the receiver/dryer.

Peter

Thanks so much for the reply!

I'll try testing the fan tonight if I get time, and will trace the wiring back to the block. I had assumed that the sending unit for the dash temp indicator did double duty- and activated the fan over a certain temp, but will see what I can find out.

Also- I had assumed the fan clutch to be of the magnetic type- but that was solely based on checking it in my service manual cd. I'll be looking for black sticky goo as well! Thanks again- J

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

another reason not to buy parts from the dealer.