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expansion tank boiling after use

ANDYMC_TQS Aug 25, 2011

  1. ANDYMC_TQS

    ANDYMC_TQS Member

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    hi iv searched for hours to find a similar prolem but havent found one yet.
    basically whenever i use my car it drives fine at the temp guage sits nice and steady at 90 as it should and never passes that but when i turn the car off i can hear the water in the expansion tank boiling like a kettle and its obviously very hot there too. i checked the thermostat and that is working perfectly so not the problem,
    i checked the water pump and although it was in perfectly good order i changed it to a new one with a metal impellar.
    i also checked the rad and big hoses for blocks by running a hose through thm but good flow.
    i did find a load of browm sludge in the expansion tank so cleaned that thoroughly

    but once i re-assembled the car the promblem still remains
    does anyone have any ideas they would be greatly apreciated
    andy
     
  2. s3dave

    s3dave TFSI Hybrid Supporter

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    Maybe a faulty seal around the expansion tank?
     
  3. ANDYMC_TQS

    ANDYMC_TQS Member

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    i did find half an oring in the tank actually the size of a 10p but i dont know where its come from or where the other half is
     
  4. colicabcadam

    colicabcadam Guest

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    change the lid of the coolant chamber, chances are it's lost its air tight seal - no pressure = lower boiling point

    with an air tight system, i believe the boiling point of water / coolant is something like 125c
     
  5. ANDYMC_TQS

    ANDYMC_TQS Member

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    ok thank you i will give it a go
     
  6. colicabcadam

    colicabcadam Guest

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    they are only like £5 too
     
  7. Smokey_clark

    Smokey_clark 12th Gear

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    What he said..
     

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