I think that the fan clutch on my '92 190E 2.6 may be failing. Even though it has been hot here in Arkansas lately, I am almost positive that the aux. elec. fans are coming on much sooner and staying on longer. I try to let it cool off a little after pulling into the garage on a hot day, before turning the engine off. I will often increase the idle speed to around 1500 and wait until it cools enough to turn off the electric fans. They will not shut off any more, they just keep running, and the temperature stays just above 100. Cruising along about 45 mph it runs somewhere in the 80's. I can spin the main engine fan when the engine is hot, and it will turn 90 degrees or so, and then stop. I called the dealer to order a new fan clutch, and the parts guy said that they had never ordered one before, therefore it was probably something else. I checked on Fastlane, and the part is not available.

I feel fairly confident with my diagnosis, but as the new part is $150.00, I thought I might ask you guys if you agree with me before I take the plunge.
Thanks!
George

If the fan clutch runs off a thermostat through a wire check them first, the're cheeper.

As far as I can tell, there is no wire. I think that it is the viscous type clutch, which engages when the oil contained inside the clutch heats up and expands.

Make sure your thermostat is operating properly first. It only take 2 minutes to remove. My 2.6 had the same symptoms and it was the thermostat. It was puzzling because it would open just a crack and the circulation at highway speeds would get the temp around 80 and would rapidly go up past 105 at a stop light or in traffic. I thought it could'nt be the thermostat at first because it never would boil over. The thermostat is about $25. If you are going to do the fan clutch, you are going to need to purchase at least one special tool or improvise to get the fan clutch off. There is a special tool that holds the fan pulley so you can remove the center bolt. Also a special short hex socket to get the fan allen bolt out, as you know it is very tight working on the front of the engine.
It is far easier to start with the thermostat. The fan clutch is not a fun job.

__________________
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T

Well, I will give it a try first, as this is what the parts man suggested also. I just wish I could get a better handle on how these viscous fan clutches are supposed to act under different conditions. I am having a similar problem on an old Dodge Motorhome with a 440 engine. I have already replaced everything on it. When its fan clutch engages, you can definiltely hear the increased "roar" of the fan blades. I hear nothing like this on the Mercedes. I saw the special tool in the manual, and they do not have it at the dealer, but it looks like I could make one out of a steel rod of some sort. It just holds the pulley so you can unscrew the center bolt, right? It is cramped up there though!
Thanks for the input!
George

Well, I hate to admit it, but I ran to Auto Zone and found a thermostat made in Germany by a company named "Wahler", I believe, for about $14.99. It was after 7 p.m. here, and nothing else would have been open. ( I can always put in a better one later, right?) I put it in, and at first test, it seems to be working. Thank you JDUB, I hope it continues to work tomorrow in the heat of the day, but I bet it does. I still have lots to learn! What a dream these cars are to work on, at least compared to what I have been used to, or at least this job, or whatever!
Thanks again!
George
1992 190E 2.6
1995 Plymouth Voyager
1973 Land Rover
1971 VW Bus
1967 Dodge(Travco) Motorhome

Wahler is a pretty good brand. Don't worry about getting a better thermostat.
You can buy the holding tool through ************************. Get the 190 catalog. But buy your parts here, you know what name brand that your getting and the prices here are better. Also get the Hazet drain plug wrench for your differntial and trans drain while your at it.

__________________
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T

All 190E 2.6 run over 100 in hot weather with the A/C running or not at idle or slow moving. Don't waste your time.

Well, all seemed to work today during an hour long run thru town around noon time, with lots of stop and go driving. It never once topped 100, and I never heard the aux. elec. fans kick on. The old thermostat must have been failing since I bought the car last August and was just getting progressively worse over time. Thanks again to JDUB for sharing his similar experience with me.
George