R129 500sl Overheating in Traffic

Discussion in 'Engine' started by Miro 0606, Aug 22, 2017.

  1. Miro 0606

    Miro 0606 New Member

    Messages:
    5
    Joined:
    Aug 21, 2017
    Car:
    500sl 500sec W123 280e 280sl
    Hello everyone.
    I'm new to the club.


    I'm having an overheating problem with my car when in traffic the temperature goes up to 115.
    So far I replaced the water pump, radiator, thermostat, all three switches, viscous fan, belt, tensioner.
    I also done the test for CO2.
    There's no coolant loss.
    There's also cold start problem, for first 2 min the battery light com on, and you can feel misfire.
    After couple of minutes the lights gone off.
    I swapped the alternator, all fuses and the OVP relay, Battery.
    It made no difference.
    Does anyone went through this problem?
     
  2. rifiki

    rifiki Active Member

    Messages:
    367
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    Jun 4, 2014
    Car:
    clk 280 Ponton 190
    Over heating, sediment in radiator/engine?
     
  3. Charles Morgan

    Charles Morgan MB Enthusiast

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    Car:
    Mercedes 250CE W114, Alfa Romeo GT Coupe 3.2 V6
    Which car are you talking about?
     
  4. OP
    OP
    Miro 0606

    Miro 0606 New Member

    Messages:
    5
    Joined:
    Aug 21, 2017
    Car:
    500sl 500sec W123 280e 280sl
    1990 500sl
     
  5. OP
    OP
    Miro 0606

    Miro 0606 New Member

    Messages:
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    Joined:
    Aug 21, 2017
    Car:
    500sl 500sec W123 280e 280sl
    I replaced the radiator and flushed the engine- there's nothing to indicate there's a blockage- wouldn't the car overheats on the long run if there was a blockage?
     
  6. brucemillar

    brucemillar MB Enthusiast

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    Car:
    C55 AMG Wagon - W124 300te 4matic Wagon - BMW 4.8is X5 E53 - SWB Pajero 3.5 V6 24v
    Sounds simple.......BUT.

    Replace the rad/header cap. A microscopic leak here will allow pressure to blow past as steam, so you will never see it with the bonnet closed (maybe not even with the bonnet open). It it blows past then you will have no coolant pressure so will rapidly overheat when standing still or climbing hills.

    Also check the hose from the header tank, to the radiator and any joints at the radiator and the header tank. Same issue with tiny leaks allowing pressure to blow by.
     
  7. OP
    OP
    Miro 0606

    Miro 0606 New Member

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    Car:
    500sl 500sec W123 280e 280sl
    Sorry forgot to mention I replaced the radiator cap.
     
  8. brucemillar

    brucemillar MB Enthusiast

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    Have you had a pressure test?

    Have you calibrated the gauge?

    How are you reading the overheat? If it is only from the gauge and you have no coolant loss and no visible sign of leakage? The the gauge should be considered suspect.

    You should also try an infrared thermometer. That will allow you to see exactly where the temps are at in part of the engine/system at any time.
     
    Last edited: Aug 22, 2017
  9. OP
    OP
    Miro 0606

    Miro 0606 New Member

    Messages:
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    Joined:
    Aug 21, 2017
    Car:
    500sl 500sec W123 280e 280sl
    I haven't done the pressure test yet. It is the next thing on my list- never done it before any advice would be appreciated.
    The gage reads correct. There's no visible coolant loss.
    The car is steaming hot I checked the temperature manually. I will try to check the temperature with infrared Thermometer, what should I look for?
    Thanks
     
  10. brucemillar

    brucemillar MB Enthusiast

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    C55 AMG Wagon - W124 300te 4matic Wagon - BMW 4.8is X5 E53 - SWB Pajero 3.5 V6 24v
    Okay.

    1) Boil a kettle and point the infrared thermometer into it. It should read 100 Degrees C. But whatever the reading remember to add or subtract the difference when you measure at the engine.

    2) Run the car up to 'normal' temp.

    3) Point the thermometer at the top hose and read it.

    4) Point at the top of the rad.

    5) move down the rad going side to side. You are looking for any cold spots that will indicate a blocked or sludged rad.


    Basically you should see the temps lower as you go drop lower for the top end to the bottom end. Most cars will sit at around 90c with antifreeze added 50/50.
     
  11. LvR

    LvR Member

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    Location:
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    Car:
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    IMO with no coolant loss as stated, all the tests already done and all the parts replaced there can only be one answer ...................

    My guess is the engine was run on a pure water diet over the years iso a coolant mix that would prevent rust - the result is that block's internal coolant passages are now covered in rust that is acting as an insulator and all the new stuff in the world will not be able to remove any more heat from those contaminated surfaces.

    Plausible?
     
  12. brucemillar

    brucemillar MB Enthusiast

    Messages:
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    It is plausible, very plausible. A good strong coolant flush left in for a couple of days should clear most of any build up. In my experience most of these issues are simple fixes with some being quite humorous.

    * Blocked heater Matrix.
    * Rad Cap.
    * Viscous or electric fan blade re-fitted back to front.
    * Viscous fluid dried out.
    * Unseen micro leaks, allow the pressure to escape and lower the boiling point.
    * No overheating but a poorly calibrated gauge (this is very common).
    * Running AC with hot weather and a lack of fan cooling.
    * Debris. between the AC condenser and the Radiator
    * Blocked Radiator Core.

    A pressure test may/should expose any leaks. You can get a bright dye added to the coolant to spot any leaks. A compression test my highlight leaks around the head.
     

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