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w202 coolant

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by C250TD_1999_Auto, Jun 24, 2009.

  1. C250TD_1999_Auto

    C250TD_1999_Auto Member

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    Joined:
    Apr 13, 2009
    Location:
    Northants
    Your Mercedes:
    C250TD (181k), CLK 220 CDI (96k) - gone, Mondeo 1.8TD (101k) - gone, skoda Fabia vrs (tdi) 102k
    I have a W202 C250TD (1999), i recently changed the coolant (Red stuff) and using a mix of 50/50 (with de-ionised water) topped up - all good - now sits just under 80 when going to work (although can rise/fall to 80 through the journey).

    Yesterday I did a bit of early morning town driving that was "enthusiastic" and i noticed the temp gauge approaching the 3/4 up the temp guage on the dash. Is this normal? I never heared the electric fans infront of the radiator kick in (I have aircon) - but I understand they kick in at 100 and i think this maybe 3/4 up the gauge, in which case they wouldn't have kicked in? just worried as i've not seen it go up this far before?

    Also, is it normal to be running just below 80 temp? my trip to work is 35miles each way, single carriageway job -

    finally, I noticed that if i squish the main pipe going from the top of the engine into the top of the radiator i can hear a clicking noise coming from the engine block, tried a few times and always does this; is this normal?

    Just wanna make sure I haven't spannered something, or if I have how to fix it!

    cheers guys
    :shock:
     
  2. wireman

    wireman Senior Member

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    Location:
    lancashire
    Your Mercedes:
    nice 201 2.5D 1993 & very nice 129 SL500 1994
    It should run at above 80, that is 85/90 but there is no saying how accurate your temp indicator is so it may be OK, If the car takes ages to warm up the stat is going and should be changed. When you thrash it expect it to rise a little but if it rises a lot and quickly then the stat again becomes a suspect.

    The electric fans are set at 100 or so.

    Since your car is 10 years old I would suggest that if its practical change your stat soon since what you describe is symptoms similar to the first stages of thermostat failiure, the second stage usualy ends with the stat stuck open/closed/partialy open, all of which can have bad effects on engine longevity. In addition I would also replace the pressure cap.

    The click is probably the plug in the bleed hole in your engine thermostat being joggled by the rushing to and fro of the coolant as you squash the top hose, its normal behaviour dont worry.
     
  3. OP
    C250TD_1999_Auto

    C250TD_1999_Auto Member

    Messages:
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    Joined:
    Apr 13, 2009
    Location:
    Northants
    Your Mercedes:
    C250TD (181k), CLK 220 CDI (96k) - gone, Mondeo 1.8TD (101k) - gone, skoda Fabia vrs (tdi) 102k
    Cheers for a speedy reply ;) - ok, so replace the thermostat and the cap on the coolant tank?

    do mb sell the caps for these?

    Am I correct in thinking that removing the stat will result in the coolant from the engine block rushing out?

    Finally, if I buy this from merc will that come with all the seals etc? not sure if the stat is built into the housing or free from the housing either? better see how much these cost then! :shock:
     
  4. bigasotonuk

    bigasotonuk Senior Member

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    Location:
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    Your Mercedes:
    C43/55 AMG 1999 / C230K 1997
    Hi,
    The twin electric fans in front of the radiator on my W202 AMG are for the A/C, and come on with the refrigerant gas pressure via low/high presure switches in the refrigerant line (I do have a viscous fan, driven off of the water pump for engine cooling).
     
  5. wireman

    wireman Senior Member

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    Location:
    lancashire
    Your Mercedes:
    nice 201 2.5D 1993 & very nice 129 SL500 1994
    The coolant will want to fall out of the system (more slowly if you leave the cap on while it drains), some models have a drain on the bottom of the radiator (a red plastic thumb screw in one of the rads end tanks), if you are lucky the coolant can be drained out at the rad and reused. Alternatively you could take off any underside covers and it may be possible to drain it into a bucket by opening the bottom hose to radiator joint. Since you have only recently renewed it the coolant can be reused, normaly I would say don't bother reusing old coolant since it only has a usefull life of two years.

    You will need a stat and its rubber seal ring to do the job, if you have not got a new ring dont start the job untill you have one. ECP and GSF may beat MB on price with parts every bit as good as MB.
     
  6. OP
    C250TD_1999_Auto

    C250TD_1999_Auto Member

    Messages:
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    Joined:
    Apr 13, 2009
    Location:
    Northants
    Your Mercedes:
    C250TD (181k), CLK 220 CDI (96k) - gone, Mondeo 1.8TD (101k) - gone, skoda Fabia vrs (tdi) 102k
    well, i finally got round to looking into this properly (the merc was my second car until very recently) - anyway, the radiator top was getting hot but the bottom was cold (as was the bottom hose) - so I drained some coolant from the bottom pipe and the drain plug on the other side and now it's sweet - sits just under 80 until I boot it then it goes to 80 or just over - nothing more - happy days!!! I also cleaned (with the hose pipe) the intercooler - the car is transformed - it's way cool - its moves and responds with urgency - i now love my car - get panels sorted (starting to rust in places) and respray, plus transmission oil change and we're onto a winner - now looking at a w140 S class - yeah baby!!! :D
     

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