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a6 2.5 tdi oil in water help!!!

amifa Mar 12, 2011

  1. amifa

    amifa New Member

    I am a mechanic and have a problem with my audi a6 2.5 tdi bau engine code that has me exasperated!!!

    Car overheated when wife was on her way to work - tested head gasket and it failed - Head gasket went on car aaagh!! - I drove car in to workshop with the engine running ok and no oil in water. Changed both head gaskets, water pump and timing belts - car starts and runs absolutely fine, brilliant.
    However I now have neat oil from the engine going directly into the coolant system (no cream), within a matter of minutes the coolant has changed to neat oil in appearance.

    I have joined the two coolant pipes from the oil cooler together to bypass this and rule this out, but it continues to refill with oil.

    Does anyone know if there is a possible oil feed pipe that could have been reconnected incorrectly or is it a case of an oil/waterway having a crack in it allowing the oil in.

    Heads were not pressure tested but were checked to see if they were warped and the oil was not previously showing in coolant.

    As a follow up, if it is that I need to change the engine over, is it the same basic engine for all the 2.5 tdi's from 1999 to 2004 and I just need to transfer over ancilliaries?

    Mant thanks in advance for any help you can offer:yum:

  2. amifa

    amifa New Member

    any ideas anyone???
  3. PeterFD

    PeterFD New Member

    How did you pressure test the HG's.
    If the header if filling with oil where is the coolant going. Ignore the Reverse gear rating I've popped in form the other Audi Forum ( Fourth Gear )Regards Peter
    Last edited: Mar 22, 2011
  4. adamss24

    adamss24 Well-Known Member

    Cracked head...Oil cooler failures are very rare on v6 tdi engines, i never seen one with a failed cooler. Did you used new bolts on refitting of the heads ? The early AFB/AKE engines had rocker arms the later (like yours) had cam rollers so they are not the same. They are interchangeable though...
  5. amifa

    amifa New Member

    Many thanks
    Fluid colour test was carried out to confirm head gasket failure. Coolant along with oil leaves via the bottom of the reservoir bottle - no coolant in oil at any time. I can run car for 10 mins everyday and not lose oil but as soon as it begins to warm and with no coolant in at all the reservoir and coolant pipes begin to fill with oil.
    Looks to be either a cracked head or block

    I can only find the AKE engine as a replacement which I intend to use to replace the engine as this appears to be the simplest option. Is there any reason not to use this engine as a swap. .i.e. fuel pump, turbo and ancilliaries are all the same.
    Thanks in advance
    Last edited: May 23, 2011

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