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a4 2.5 dti time for belt change help needed

davek Apr 6, 2011

  1. davek

    davek Member

    Hi all
    Going to change the timing/pump belt soon.
    Is there a diagram for the timing marks about.
    i have done a search but came up with things
    completly different.
    thank you.
    dave king
  2. adamss24

    adamss24 Well-Known Member

    I would not attempt-it without locking tools as its very easy to screw-up the engine ! Where abouts are u based ? If not too far from n. london come to me and i will do- it for you , drop me a pm for a price. The cams are on a tapper and to properly time the engine and tension the belt corectly allong its whole lenght, the cam pulley's need taking off the camshafts. You need to lock the cams and crank + injector pump pump needs setting via dedicated diagnostic equipment. The clearances are very small and if the "mark and pray" method is used severe damage could result from pistons hitting the valves. The cost will be high due to the ammount of parts required for a propper job. The water pump needs re-newing at the same time allong with tensioner, aux. roller and the vibration damper (this on its own is over 100 quid from dealer!). Also its wise to replace the thermostat and seal while the car is in pieces as the thermostat ussualy goes soon after a cambelt and will require cambelt removal. I also check and repair/rebuild the aux. belt tensioner as they are known to wear out and if not cought in time-the ac bracket will need replacing wich bumps up the price. Drop me a pm or call 07789912128 for more details. regards,
  3. davek

    davek Member

    Thanks for your reply.
    I have a full universal locking kit and have done many over the years.
    The belt has done less than 200 miles as the pump packed up and it has been sat
    for 2 years.
    thanks again.
    dave king
  4. PAULF

    PAULF Active Member VCDS Map User

    Wot Adamss24 said!

    The problem you will have is that after timing it statically (which you can do like any other engine.There is a slot in the back of the camshaft and a pin in the pump, to get things started look through the oil filler and turn engine until you see OT(IIRC) on the camshaft) you will need to use VCDS or similar to check the dynamic timing. You MAY be lucky, but when I checked mine it was quite far out. This can involve a lot of fiddling to get correct.
  5. PAULF

    PAULF Active Member VCDS Map User

    Just a thought, but if the belts etc were changed, and then 200 miles later the pump failed, you may find the pump is ok.
    If the tensioner was not set properly, the belt will move over a period of time.
    You need to scan with VCDS and check for pump related codes. If you have any, clear them, and them try and start the car. If the car doesn't start, a look at Block 19 in the engine module will tell you what the dynamic start injection is (should be between 2.0 ATDC to 4.7 BTDC). If it is not, adjust the pump sprocket until it is within limits. If it does start, check the dynamic timing using Block 4, Basic setting, TDI Timing. The car will rev up and down a little as the timing is changed between advance and retard.
    If this is the case, you could save yourself a lot of hassle and money!
  6. a8 tech back

    a8 tech back Member

    As above but the belts are not difficult to replace and the most common issue is the lower tensioner incorrectly set up, the belt becomes slack and valve timing moves but normally no damage occurs as the engine just idles
    If this is the case just realign the crank and cams and set the tensioner up and then check dynamic timing with vcds
    If the pump has failed then its more likely to be the pump control unit pcb which can be repaired for a fraction of the cost
    A quick spray of easy start into the intake will confirm if the pump no longer induces fuel however beware as this also increases compression so if timing is ok squirt some in and if it then runs off easy start and you can see no fuel entering via the fuel pipe its likely the pump control unit has failed.However check fault codes and pre supply pressure as well
    Pretty straight forward no real need to panic
    Good luck
    Last edited: Apr 7, 2011

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