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Renewing valve stem oil seals with cylinder head installed > < Removing and installing camshafts and camshaft adjuster

A4 Mk2

Checking hydraulic bucket tappets
Checking hydraulic bucket tappets
Special tools and workshop equipment required
t  Feeler gauge
t  Wooden/plastic wedge
Test sequence
  Note
t  Hydraulic bucket tappets cannot be serviced.
t  Irregular valve noises when starting engine are normal.
–  Start engine and leave it running until coolant temperature has reached approx. 80 °C.
–  Increase engine speed to approx. 2500 rpm for 2 minutes (perform road test if necessary).
  Note
If the irregular valve noises stop but recur repeatedly during short trips, renew the oil retention valve. Fitting location of oil retention valve: beneath cover on intake manifold → Item.
If the hydraulic tappets are still noisy, locate defective tappet as follows:
–  Remove cylinder head cover: left-side → Chapter, right-side → Chapter.
   
–  Vehicles with auxiliary heater: remove bolts -arrows- securing exhaust pipe for auxiliary/additional heater to noise insulation.
  A10-0407
–  Release bolts or quick-release fasteners -1- and -2- and take off front noise insulation.
  A10-1320
–  Rotate crankshaft clockwise at central bolt for toothed belt sprocket until cams of cylinder to be checked are pointing upwards -arrows-.
  A13-0472
–  Push bucket tappet down with a wooden or plastic wedge to determine play between cam and bucket tappet.
If it is possible to insert a feeler gauge of 0.20 mm between camshaft and bucket tappet:
–  Renew bucket tappet → Chapter „Removing and installing camshafts and camshaft adjuster“.
  V15-0880

Renewing valve stem oil seals with cylinder head installed > < Removing and installing camshafts and camshaft adjuster