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SL55 Coolant Light - Please help

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by azam6380, Nov 5, 2012.

  1. azam6380

    azam6380 Senior Member

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    Hi Guys,

    Problem with my SL55 unfortunately. The coolant light came on the other day, obviously thought it would be something simple but when I came to fill up the coolant, the coolant tank was full. The engine fans turn on everytime I start the car but the temperature remains constant at 80.

    I thought it was a malfunctioning temp sensor so left it at the garage this morning. Just spoke to them and they said they are trying to etablish what the problem is but they arent sure.

    They said the ECU isnt giving off the right voltage, apparently less than it should? (Does that make sense) or the fan might be defective.

    Either way - this could end up costing me loads....cira 1k.

    Does anyone have any thoughts or something to cheer me up!

    :(
     
  2. OP
    azam6380

    azam6380 Senior Member

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    Apologies if I have posted this in the wrong section...
     
  3. television

    television Always remembered RIP

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    The header tank is wired in series with the washer tank, and either sensor will cause this
     
  4. andy@pcd-ltd

    andy@pcd-ltd Guest

    Do you know if there was any fault codes stored in the ecu
     
  5. OP
    azam6380

    azam6380 Senior Member

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    They dont know what the problem is yet. and I don't know what the code was either Im afraid. I hope its nothing too grim. have a sick feeling at the moment!
     
  6. OP
    azam6380

    azam6380 Senior Member

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    Thankyou Malcolm. In layman terms, is that expensive to fix? and do you think that is likely to be the problem?
     
  7. television

    television Always remembered RIP

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    The sensors are resistive and either one could be faulty, not that expensive,,,one of these days I must measure them so that we have a reference to work to
     
  8. OP
    azam6380

    azam6380 Senior Member

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    Thankyou-I will explain this to them
     
  9. OP
    azam6380

    azam6380 Senior Member

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    Hi Malcolm, I just spoke with the garage and they have no idea what I mean by the Header and Washer tank sensors? They asked if I meant the windscreen washer tank.

    Sorry, I'm a total noob with this part of the car, what would you suggest i tell them?
     
    Last edited: Nov 6, 2012
  10. OP
    azam6380

    azam6380 Senior Member

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    They have indicated that the voltage readings from the ECU are very strange. Groan. I'm so clueless!
     
  11. toby1

    toby1 Senior Member

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    I'd find another garage TBPFH
     
  12. OP
    azam6380

    azam6380 Senior Member

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    :(
     
  13. Alps

    Alps Senior Member

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    azam, id agree with the above, what garage have you taken it to? are they a MB independent? or back street garage.

    they really dont sound like they know whats going on!
     
  14. OP
    azam6380

    azam6380 Senior Member

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    They are a proper Mercedes/BMW garage in South London. Not a smalltime operation by any means! Do you guys know exactly what the header and washer tank are? Sorry, I've not got a clue.
     
  15. toby1

    toby1 Senior Member

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    Header tank is usually the expansion bottle for the coolant.

    Washer tank? - at a guess the windscreen/headlamp washer bottle
     
  16. television

    television Always remembered RIP

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    Yes as Toby header tank and washer tank wired in series in a resistive circuit
     
  17. OP
    azam6380

    azam6380 Senior Member

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    Right...So i need to tell them to check the sensors in the Header tank (expansion bottle for the coolant) and the washer tank (windscreen/headlamp washer bottle)?
     
  18. OP
    azam6380

    azam6380 Senior Member

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    as these have 2 sensors that work in tandem and if one fails the fan will come on and the coolant light will go on? Apologies for my asinine questions.
     
  19. television

    television Always remembered RIP

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    Correct :D
     
  20. television

    television Always remembered RIP

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    A piggy job as the off side wheel arch liner has to come off (rear section)
     

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