audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

ABOUT US
Renewing valve stem oil seals > < Removing and installing camshafts and camshaft adjusters

A4 Mk2

Checking hydraulic bucket tappets
Checking hydraulic bucket tappets
Special tools and workshop equipment required
t  Feeler gauge
t  Wooden/plastic wedge
  Note
t  Hydraulic bucket tappets cannot be serviced.
t  Irregular valve noises when starting engine are normal.
Procedure
–  Start engine and run until coolant temperature reaches 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 → Chapter.
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.
–  Rotate crankshaft clockwise at centre bolt for toothed belt sprocket until cams of cylinder to be checked are pointing upwards.
–  Determine clearance between cam and bucket tappet.
  A10-1320
–  Push tappet down with a wooden or plastic wedge. If an 0.20 mm feeler gauge can be inserted between camshaft and tappet, renew tappet.
–  Renewing tappets → Chapter „Removing and installing camshafts and camshaft adjusters“.
  Note
t  After installing the camshaft, the engine must NOT be started for about 30 minutes. Hydraulic valve compensation elements have to settle (otherwise valves will strike pistons).
t  After working on the valve gear, turn the engine carefully at least 2 rotations by hand to ensure that none of the valves make contact when the starter is operated.
  V15-0653

Renewing valve stem oil seals > < Removing and installing camshafts and camshaft adjusters