Fan Clutch W126 is repair possible ??
 

:confused: I believe that my fan clutch is dead and a new one is $200. Is there a way of fixing it. It's -25f here and when I accelerate I can really hear the fan whirr away. Even at idle in the cold it kicks on and off and my car will only get up to 52deg Celsius maybe 70c when in traffic for 1hr. The point is I can really hear it spin up when revving. and it never runs slow any more.

Is there a fix?

No there is no fix, it sounds like its locked up and therefore very noisy at speed, bite the bullet and buy and new one, try ebay , Larry:)

Replace the clutch. Don't wait or you will throw a blade though something expensive.


I don't recomend it, but during the winter I have run the diesels without them for various reasons. The engines ran slightly warmer at idle but other than that no change. Of course when its 30 degrees out diesels don't produce much heat.

No matter what you determine to be the temporary fix, eventually you will need to repalce the clutch as there is no way to fix a bad one and as soon as it gets warm again, you will need to rely on a funtioning cooling system. New ones online are a better cost than dealer and not really any different, used ones are a dangerous deal since they may be on their last leg also. no way to determine a fan clutch's remaining life span.

$200 is cheap for a fan clutch. Just be glad you don't have an M119 as that clutch will set you back more than 2x as much.

Replace it - that fan was not designed to turn that fast and failure will be catastrophic.

you guys are right
 

it's 4.2 V8 and it is -15c out side but I think I still need the fan. I will buy one from eBay for $129. Does any body here know what temp the 4,2L V8 runs when it's below freezing? Is 60c-70c too low? Or even 50c engine temp??

I bet fan clutch is keeping it from getting to normal operational temperature.

420 Fan Clutch
 

I saw a post on a fix a long time ago; I remember it saying you could fix the fan clutch by drilling a small hole on the back and refilling it with some special heavy oil used for Toyota fan clutches using a Turkey baster syringe, then plugging the hole back up with solder, liquid solder or epoxy. I understood what goes wrong with the fan clutch is that oil leaks out or looses viscosity. Never tried it so I don't know if it works but it is a cheap fix that I understand works for Toyotas.

buy a new one.....

In my opinion the fan clutch is too important, at too big of pain to replace ( not hard,just a pain) to not buy a new one. Maybe not OEM MB parts, a replacement part would be fine, but buy a new one, install and forget about it. Engine temps are not something to play with and I have seen what a fan flying around in the engine compartment can do, it is not pretty.

just as an aside you probably have thermostat issues as well because no matter how fast the fan is turning the t/stat should not open until the engine is up to temp.you are relying on the fan to get rid of excess heat not to keep heat in the engine.

thermostat
 

has anyone had a hard time replacing a thermostat on a w126 420sel? I know on GMs the 2 bolts are always seized ... and they break is this an issue with Mercedes? :confused:

My pal's Suburban came out fine (TBI 350, 1989 model)...

Hit with some penetrating oil if you're paranoid.

Here I go
 

Fan clutch seems to have smartened up a bit but the thermostat is being replaced now. Here goes nothing. Maybe I will photograph it and add it to the Do It Yourself section.