W204 overheating, cooling fan not working, any ideas?

Discussion in 'Engine' started by razzer21, Dec 15, 2016.

  1. razzer21

    razzer21 New Member

    Messages:
    8
    Joined:
    Nov 30, 2015
    Car:
    2010 W204 C200 CDI
    Hi All,

    I have a 2010 W204 C200 Cdi with the OM646 engine.

    It has recently started to get hot when in stationary traffic but the engine cooling fan fails to kick in.

    The temperature gauge went to around 100 then I got a warning symbol in the multi function display, the symbol I got points to a fault with the electronic cooling fan according to my hand book, rather than an overheating error symbol.

    I have checked the coolant and all is good.

    I am assuming it could be a fault with either the sensor which brings the cooling fan on or the fan itself which is faulty?

    Can anybody advise any checks I can carry out before taking it to the main dealer?

    I am able to check voltages & resistances if anybody can point me in the right direction and the location of the components?

    Thanks in advance.
     
  2. W210Virgin

    W210Virgin Hardcore MB Enthusiast

    Messages:
    255
    Joined:
    Feb 25, 2014
    Location:
    Norn Iron
    Car:
    2002 S210 Avantgarde 320CDi in silver. Black leather interior
    Start by putting 12V on the fan directly from the battery and see if tit can get it to run.

    Sent from my SM-G935F using Tapatalk
     
  3. ioweddie

    ioweddie Hardcore MB Enthusiast

    Messages:
    1,303
    Joined:
    Sep 16, 2012
    Location:
    Winford Isle of Wight
    Car:
    AMG Line Premier Plus Estate C220d
    water pump is a common failure on W204 as its plastic
     
  4. cws196

    cws196 Hardcore MB Enthusiast

    Messages:
    234
    Joined:
    Jan 4, 2013
    Car:
    S204 C250 Estate AMG Sport Plus - 2013
    I thought it was only the OM651 with the plastic water pump?
     
  5. PSPet

    PSPet New Member

    Messages:
    1
    Joined:
    Dec 12, 2016
    Car:
    Mercedes Benz CLS
    I agree that it is probably a problem with the cooling fan relay rather than the fan itself? Or perhaps the temperature switch or computer that triggers the cooling fan relay to jump start the fan is faulty. I had this problem once and it turned out there was some problem with the temperature detection of the temperature switch that resulted in the fan not being switched on. At the time I ordered new parts from autozone as I found this website with discount codes. Perhaps it is useful for you too!
     
  6. OP
    OP
    razzer21

    razzer21 New Member

    Messages:
    8
    Joined:
    Nov 30, 2015
    Car:
    2010 W204 C200 CDI
    Thanks for all your replies.

    I connected the fan directly to a 12v supply and it did turn but only really slowly.

    However on the plug to the fan, there was 2 x thick wires, a brown and a red and also 2 thin wires, one green/blue wire and one red/black wire.

    I connected 12v onto the thick wire connectors only, but the fan only turned slowly.

    When I spin the fan by hand it sounds like plastic grating on plastic but its free to spin. Tried taking resistance readings but it was very inconclusive.

    Its the Bosch fan, part number: 3136613344

    Any suggestions appreciated.

    Thanks
     
  7. kid-jensen

    kid-jensen Hardcore MB Enthusiast

    Messages:
    1,153
    Joined:
    Dec 16, 2002
    Location:
    Epsom Downs
    Car:
    ML 320 W164
    Take the Fan Motor apart, clean up all the carbon dust and grease the bearings?

    Check the condition of the brushes whilst it's apart...
     

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