fan switch - where is it?

[james watson]

Hi all,
       the thermo viscous cooling fan on my 91 260e,which worked fine till now,has suddenly stopped cutting in(works at 102.C) I have checked the fuse which is ok, and my next port of call is the fan switch.
Where exactly is it on the engine,and is this a likely cause of the problem(am worried it may be the fan coupling which is a bigger job)
thanks in anticipation
jim

 

[Andy]

fan switch

Hi

The fan on your model is NOT operated electronically. It is a viscous operated model. The only fans which may be operated electronically would be the auxillary air fans for the AC system.

Regards

Andy @ www.mercedesservicing.com

 

[james watson]

fan switch

Andy,
        Thanks for replying-so am i correct in assuming that if the fan does'nt switch on when it should and there's no fan switch,then i need to replace the fan coupling,or are there any other areas i need to check before doing this?
thanks

jim

 

[Andy]

fan switch

Hi James

What exactly is the problem James. Is the vehicle over heating?

Does it have AC fitted?

Let me have the answers to these and we will see if we cant set you on the right track

Regards
Andy @ www.mercedesservicing.com

 

[james watson]

fan switch

Andy,
       Thanks for your continuing help!
Basically its not overheating-BUT! the fan is'nt cutting in when it should. It used to cut in when the temp gauge reached 100.c- (i know this because you could hear the extra fan noise from the front of the engine when you revved it-lot louder than normal)which brought the temp down fairly rapidly to about 85.c.
At the moment, when the temp gauge reaches 100.c (usually in heavy traffic),it keeps rising albeit without overheating ,to well above 100,and the fan does'nt cut in as it used to.
It is'nt actually overheating in traffic,but it is getting fairly hotter than it should do and it is  something that i would like to fix to sort out before we enter warmer weather.
Also i don't have any AC fitted
I was told it was the fan switch-i presume there is one as euro car parts sold me one!(although they may be wrong)


thanks for your time
jim

 

[Matt Crooke]

fan switch

Following on from Andy's replies, as he says there is no electrics involved in a Viscous fan. Its merely a gel like substance inside the fan coupling, that congeals when then heat from the engine reaches a certain temparature, thus locking the fan on and spinning the same speed as the engine. They do pack up after a while, ive had 2 go on a couple of Granada's i used to own.

 

[Andy]

fan switch

Hi,

Well 260e's arn't fitted with fan switches. I can't comment on what you are actually hearing. But if the engine temp is not going much over 100 when ticking over in traffic then I wouldn't bother. You could check and make sure the radiator is hot all over. Thereby checking the water is flowing throughout the radiator. If there any cold spots then get the rad checked.
Again the fan is a viscous type and sense the temp of the radiator. You are down to two components either the radiator is faulty or the fan coupling. If with the engine stoped the fan has plenty of friction to move it then I would say that it ok.

Trouble is as you say. The car has never overheated. So I am not sure there is a problem.

Regards

Andy @ www.mercedesservicing.com

 

[David Halsey]

fan switch

Is the cowling onb the rad complete or missing/broken

viscous couplings rely on residual heat in the vacinity to operate.
If the cowling and even the undersheild is missing then too much air gets to the area, keeping the local temp down and stopping the coupling to not operate.

 

[james watson]

fan switch

Hi ,
   no- all the mounting/undertrays are ok-i had a new rad installed earlier this year.
Maybe i'll get the coupling changed.
jim