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1990 W124 230e cooling fan query.

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by kraM, Oct 3, 2019.

  1. kraM

    kraM Member

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    Your Mercedes:
    1999 CLK 340
    Hello,
    My car (above) has recently been getting warm in traffic (electric fan doing its job). The main fan spins freely, even when hot. I can easily stop it whilst it ticks over.
    After much head scratching, I managed to get it off, and looking at it, it has a very simple bi-metallic clutch operation.
    I've tested it with a kettle of boiling water. It didn't change shape.
    Before I buy a new one, are these Bi-metallic, or am I being a biff, and they are somehow magnetically operated?
    The only replacement I've found is about £120! Are they common parts to fail?

    Thank you.

    Mark.
     

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  2. LostKiwi

    LostKiwi Senior Member

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    Your Mercedes:
    '93 500SL-32, '01 W210 Estate E240, 02 R230 SL500 (Malcolm Spec), 04 Smart Roadster Coupe
    Not sure about yours but some cars use a silicon oil that paradoxically gets thicker as it gets hotter.
    Toyota do this on Landcruisers. Toyota do small bottles of the oil for repairs.
     
  3. d215yq

    d215yq Senior Member

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    Your Mercedes:
    1987 W124 300D 250k
    Aren't they all viscous couplings - had to replace a coupling on my W124 E220 so newer than yours so would assume yours defintiely has it? IIRC it was 40 for the part (not the whole fan) but I couldn't fit it myself so not exactly sure of the breakdown. My later E220 estate had the same problem and I just used the heater when sat in traffic for the whole time I owned it,..but neither of those had the electric fan, so it might be enough to just rely on that unless you regularly drive in queueing traffic, particularly now summer is over?
     
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  4. star

    star Forum Supporter Authorised Forum Supporter

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    That’s not a bi metallic strip or viscous fan coupling. That is just part of the “clutch” that is enguaged by the electro magnet under the water pump pulley. This is switched on by the fan temp sensor set at 100’c.
     
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  5. grober

    grober Senior Member

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    Your Mercedes:
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    At 1990 the 230 will have the 2.3 litre version of the M1O2 engine hence the electromagnetic clutch like the 4 cylinder petrol 190
     
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  6. Bogus

    Bogus Active Senior Members

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    Your Mercedes:
    W124 230E 1992. Toyota Hilux Surf 3rd gen
    You probably need a new fan switch, cost around £10.
    Its the switch they are messing with in this video

     
    Last edited: Oct 4, 2019
    kraM likes this.
  7. OP
    kraM

    kraM Member

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    Excellent, thank you very much, you've been a massive help (and saved a few quid too!) I'll be checking it tonight.
     
  8. star

    star Forum Supporter Authorised Forum Supporter

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    Two different switches, single and twin pole.
     
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  9. OP
    kraM

    kraM Member

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    After testing the loom, where both wires to the magnet go to ground?!? I pulled out apart to find no fault, gave the magnet 12v and it worked perfectly. Tested the switch and nothing (in the kitchen with the switch suspended in a saucepan of boiling water via a metal coat hanger, when my wife walked in...)
    Switch now on order.
     
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  10. OP
    kraM

    kraM Member

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    Hi, all fixed now. For others with the same problem, it's the Red sensor (two pin) at the front of the head. There is also a single connector under the air cleaner and a bolted earth.
    Sensor replaced, didn't loose more than a few drops of coolant.
    Thank you.
     
  11. Bogus

    Bogus Active Senior Members

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