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Renewing valve stem oil seals with cylinder head installed > < Removing and installing camshafts and hydraulic chain tensioner

A4 Mk1

Checking hydraulic bucket tappets
Checking hydraulic bucket tappets
Special tools and workshop equipment required
t  Feeler gauge
t  Wooden/plastic wedge
Procedure
  Note
t  Hydraulic bucket tappets cannot be serviced.
t  Irregular valve noises when starting engine are normal.
–  Start engine and run until radiator fan has started up once.
–  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. The oil retention valve is located in the oil filter bracket → Item.
If the hydraulic tappets are still noisy, locate defective tappet as follows:
–  Remove cylinder head cover → Chapter.
–  Turn crankshaft until cams of bucket tappets to be tested are at top:
   
t  On vehicles with manual gearbox: push vehicle in direction of travel with fourth gear engaged and ignition switched off until “TDC” marking on vibration damper aligns with marking on bottom section of toothed belt cover -arrows-.
t  On vehicles with automatic gearbox: rotate crankshaft to “TDC” by turning toothed belt sprocket bolt in direction of engine rotation.
  A13-0154
–  Push bucket tappet down with a wooden or plastic wedge to determine play between cam and bucket tappet.
–  If an 0.20 mm feeler gauge can be inserted between camshaft and tappet, renew tappet → Chapter „Removing and installing camshafts and hydraulic chain tensioner“.
  V15-0880

Renewing valve stem oil seals with cylinder head installed > < Removing and installing camshafts and hydraulic chain tensioner