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W124 E220 Overheating - Thermostat?

Discussion in 'Engine' started by Blackman, Aug 19, 2010.

  1. Blackman

    Blackman Hardcore MB Enthusiast

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    Car:
    1998 W124 E220 Saloon
    Got a weird problem with my W124 E220. When driving along in the city/motorway, the temp gauge sits nicely around 80/90 mark.

    As soon as I get stuck in traffic, it slowly starts going up, and the last time it went up as high as 100-110 :eek:

    Then it goes down again, when I start moving...

    Am I right that it's the thermostat? Done some searching on the forum, and found that the part number is: A 111 200 09 15 and it's about 20 quid from MB?

    It's for a Coupe, but should be the same for a Saloon, isn't it?

    Any help appreciated.

    Thanks
     
    Last edited: Aug 19, 2010
  2. Adam230K

    Adam230K Hardcore MB Enthusiast

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    WHy dont you check to see if your car is truly overheating or not. While you are sitting in traffic, put your heaters on full blast, as hot as the car will allow and see if the heat goes down. If it doesn't you have a cooling issue I think
     
  3. Uncle Fester

    Uncle Fester Hardcore MB Enthusiast

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    Have you checked the coolant level of the car?

    Start with the basics, when was the coolant last changed?

    Do you have the correct concentration of coolant?
     
  4. d w124

    d w124 Hardcore MB Enthusiast

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    I doubt is the thermostat but you never know.Why not bypass the thermostat first and see if it cures the problem.The coupe saloon and estate have the same one
    Most likely is the fan but check first
     
  5. kth286

    kth286 Hardcore MB Enthusiast

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    that is likely a pump problem.

    the impellar is likely to be eaten away because the coolant solution mix is wrong - it should be 50/50 water and coolant solution mix.

    you have likely got too much water which has allowed corrosion of the cooling system components.

    your car should be capable of sitting in traffic for a long time with the temperature staying steady 90 ish. A good pump even at idle should still be capable of sending the coolant around the radiator circuit and therefore cooling the liquid; but a worn impellar will hardly be moving the water around the circuit, until the engine speeds up.

    Do the simple jobs first like checking the coolant and changing the thermostat.
     
  6. OP
    OP
    Blackman

    Blackman Hardcore MB Enthusiast

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    The coolant level is ok, but not sure what's the mixture.

    In regards of the "test" with heaters, I remember I tried them a while ago, but didn't seem to make a difference. The temperature was still 100-110.

    I'll get the thermostat changed, and let's hope that will be it.
     
  7. Uncle Fester

    Uncle Fester Hardcore MB Enthusiast

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    Might as well get the coolant changed at the same time, two birds one stone. :thumb:
     
  8. renault12ts

    renault12ts Hardcore MB Enthusiast

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    Concentration will not effect cooling. You could have pure water in there and it would work the same. The concentration is for anti freeze properties and rust inhibitors
     
  9. renault12ts

    renault12ts Hardcore MB Enthusiast

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    In warm weather the temperature of the engine will rise if you are sitting in traffic. The engine fan should then take over and provide cooling. Is the fan working, ie is the viscous clutch cutting in.
     
  10. OP
    OP
    Blackman

    Blackman Hardcore MB Enthusiast

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    Checked today, and yes, the fan is working, but I think it's spinning kind of slowly? It might be the way it is, but not sure...

    Anyway, a new thermostat is on my "to-do" list.
     
  11. stwat

    stwat Hardcore MB Enthusiast

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    It could be a faulty fan switch. A quite common replacement item on the cars equipped with the electromagnetic clutch type cooling fan.
     
  12. Simba

    Simba Active Member

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    As Stu says, I would also suspect the cooling fan. They do spin slowly,this is only caused by fricton. It does not mean that they are working in the proper sense.

    I had this on my 190E,and had to replace the fan sensor. To test if the fan is properly working you need to bridge the two contacts on the plug. This should show what I mean.

    [​IMG]

    [​IMG]


    Picture one shows the plug taken off the fan sensor,picture two shows the red wire I used to bridge the two contacts in the plug.I left the bridging wire in place for a few days while I got the new fan sensor.



    Hope this helps.
     
    Last edited: Aug 21, 2010
  13. balge

    balge Hardcore MB Enthusiast

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    hi
    what car is this? Assuming '98 W124 is a misprint
    If putting the heater on doesn't cool it you have a problem, could be fan as mentioned.
    Do you have electric or viscous fan?
    My 230TE has electric fan, this should freewheel until the temp switch on the head cuts it in, when it will ROAR, and slice a carrot to death. The sensor is on the front of the head, 2 minute job to replace, cost a tenner or so
    My 300TD has a viscous fan, this should be loose but not freewheeling at rest and start driving when the motor has warmed it up a bit, when it too will start roaring away. No sensor for these fans.

    cheers!
     
  14. d w124

    d w124 Hardcore MB Enthusiast

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    No,it is not.When the stoped the production in Germany,they were buillt in India till 2001 I think and were only 220s or 250 diesel.All manual
     
  15. balge

    balge Hardcore MB Enthusiast

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    good god well I never...
    Built in India eh.....nice
    And I thought the build-quality drop between my '88 and '93 estates was a surprise...


    What fan type though, thats still the question eh?
     
  16. d w124

    d w124 Hardcore MB Enthusiast

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    He has the same type as your estate,clutch type sort of thing
     
  17. OP
    OP
    Blackman

    Blackman Hardcore MB Enthusiast

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  18. Simba

    Simba Active Member

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    Car:
    190E Sportline.
    First of all, you need to check that its the correct one for your car. On mine, a190E,it seems that two different ones were used. I got a two pin one first,wrong. When I went to put it on I saw mine should have been a three pin one. So I had to take it back and change it.I got mine in GSF,I think mine was a tiny bit cheaper than that one.


    Fitting was simple on mine. There is a plastic sheild thing which was in the way, that simply pulled off,straight up.

    Then I used a big socket,cant remember what size,just got it from my set and it came straight out.


    I would check yours first before getting a new one. If you just bridge the two contacts in the plug with a bit of wire, if its working the the fan should spring into action,if it doesnt then you will need a new one.




    Mike.
     
  19. balge

    balge Hardcore MB Enthusiast

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    Well thats the question, the two are both estates, one has electric and the other is viscous?

    cheers!

    edit pretty sure the 230TE uses a 2-pin sensor (1988)...3-pin may be for a/c systems?
    no point replacing it til you've tested it though...
     
    Last edited: Aug 21, 2010
  20. andymerc

    andymerc Hardcore MB Enthusiast

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    e220 will have a viscous coupling, your promblem is most likely the viscous coupling
     
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