Audi Workshop Service and Repair Manuals

Removing and installing toothed belt

Special tools and workshop equipment required

t	Diesel injection pump locking pin -3359-

t	Crankshaft stop -T10100-

t	Locking pin -T10115-

t	Counterhold tool -T10172- with pin -T10172/4-

t	Locking fluid → Electronic parts catalogue

Removing –  Vehicles with auxiliary heater: remove bolts -arrows- securing exhaust pipe for auxiliary/additional heater to noise insulation.

–  Release quick-fasteners -1- and -2- and take off front noise insulation. Leave rear noise insulation in position. –  Remove bumper cover (front) → Rep. Gr.63. –  Move lock carrier to service position → Rep. Gr.50.

–  Unclip cover caps. –  Unscrew nuts -arrows- and detach engine cover panel. Also pull out dipstick if necessary. –  Remove insulation beneath cover panel (if fitted).

–  Remove top toothed belt cover by releasing retaining clips -arrows-.   Note

Before removing, mark direction of rotation of poly V-belt with chalk or felt-tipped pen. If the belt runs in the opposite direction when it is refitted, this can cause breakage. –  Turn the tensioner in the direction of the -arrow- to slacken the poly V-belt. –  Remove poly V-belt from alternator pulley.

–  Unscrew bolts -3- and detach cover -2-. –  Move charge pressure control solenoid valve -N75--item 1- clear to one side with hoses connected.

–  Lever off cover cap from vibration damper. –  Unbolt vibration damper; counterhold on centre bolt with ring spanner.

–  Unbolt toothed belt cover (centre and bottom) -arrows-.   Caution The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).   Note Turn over the engine at the central bolt on the crankshaft.

–  Turn the crankshaft to TDC. l  The space between the two lugs -1- on sender wheel of camshaft must align with marking “4Z”-item 2- on toothed belt cover (rear).   Note For illustration purposes, the camshaft sprocket is shown with the toothed belt removed. –  Lock hub with locking pin -3359-.

–  Lock crankshaft sprocket with crankshaft stop -T10100-. l  The markings on the toothed belt sprocket -2- and the crankshaft stop -T10100--item 1- must align. The pin of the crankshaft stop -T10100- must engage in the aperture in the sealing flange.   Note The crankshaft stop -T10100- can only be pushed onto the sprocket from the front face of the teeth.

–  Mark rotation direction of toothed belt with chalk or felt-tip pen. –  Loosen securing bolts for camshaft sprocket -arrows-.

–  Loosen securing nut -1- for tensioning roller.   Note t  Make sure that stud is securely fitted. t  If stud is not securely fitted, apply locking fluid onto stud and screw in as far as stop. –  Using a hexagon key, turn eccentric adjuster on tensioning roller anti-clockwise -arrow- until it is possible to lock tensioning roller in position with locking pin -T10115-.

–  Then turn hexagon key clockwise -arrow- until stop and tighten securing nut -1- finger-tight. –  Take off toothed belt first from coolant pump and then from the remaining sprockets. Installing (adjusting valve timing) l  Camshaft locked with locking pin -3359-. l  Crankshaft locked in position with crankshaft stop -T10100-. l  Tensioning roller locked with locking pin -T10115- and secured at right stop with securing nut.   Note t  Toothed belt adjustment must always be performed when the engine is cold. t  The crankshaft must not be at TDC at any cylinder when the camshaft is turned. Otherwise, there is a risk of damage to valves and piston crowns.

–  Ensure that tensioning roller is seated properly in rear toothed belt cover -arrow-.

–  Screw in bolts -arrows-, but do not tighten. l  It should just be possible to turn the camshaft sprocket on the hub without axial movement. –  Turn the camshaft sprocket in its elongated hole clockwise until the stop. –  Fit toothed belt first onto camshaft sprocket, tensioning roller, crankshaft sprocket and then onto coolant pump sprocket.

–  Adjust toothed belt tension as follows: –  Remove locking pin -T10115-. –  Loosen securing nut -1- for tensioning roller.   Note When loosening securing nut -1-, make sure that the threaded pin is not loosened together with the securing nut. –  Turn eccentric adjuster of tensioning roller clockwise -arrow- using hexagon key until pointer -2- aligns with the centre of the slot on the base plate.   Note Make sure that the securing nut does not also turn. –  Hold tensioning roller in this position and tighten tensioning roller nut to 20 Nm + 45°.   Note When tightening the securing nut, the pointer may move up to 5 mm (maximum) to the right of the slot in the base plate. This position must not be corrected, because the toothed belt stretches slightly when running in.

–  Insert counterhold tool -T10172- with pins -T10172/4- as shown in illustration and apply tension to camshaft sprocket by pressing in -direction of arrow-. –  Tighten bolts -1- on camshaft sprocket to 25 Nm. –  Remove locking pin -3359- and crankshaft stop -T10100-.

Checking valve timing   Caution The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise). –  Turn crankshaft two rotations in normal direction of rotation until the crankshaft is just before TDC again. –  Lock the hub into place with the locking pin -3359- when turning. l  The space between the two lugs -1- on sender wheel of camshaft must align with marking “4Z”-item 2- on toothed belt cover (rear).   Note For illustration purposes, the camshaft sprocket is shown with the toothed belt removed. –  Check whether: l  The crankshaft can be locked with the crankshaft stop -T10100-. l  The tensioner pointer is centred or a maximum of 5 mm to the right of the slot in the base plate.

If the crankshaft cannot be locked: –  Loosen securing bolts -arrows- of camshaft sprocket.

–  Turn the crankshaft slightly further in the normal direction of rotation until it can be locked with crankshaft stop -T10100-.   Note If the crankshaft has been rotated beyond TDC, turn it back slightly so you can then reset it to TDC by turning in the normal direction of rotation.

–  Tighten securing bolts for camshaft sprocket -arrows- to 25 Nm. –  Remove locking pin -3359- and crankshaft stop -T10100-.   Caution The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise). –  Turn crankshaft two rotations in normal direction of rotation until crankshaft is at TDC again. –  Check valve timing once again → Anchor. Assembling Installation is carried out in the reverse order; note the following:   Note t  Renew seals and gaskets. t  Secure all hose connections with the correct type of hose clips (same as original equipment) → Electronic parts catalogue. t  To ensure that the charge air hoses can be properly secured at their connections, spray rust remover onto the worm thread of used hose clips before installing. –  Install toothed belt cover (bottom and centre). –  Install vibration damper → Anchor. –  Install poly V-belt → Anchor. –  Fit toothed belt cover (top section). –  Install lock carrier with attachments → Rep. Gr.50. –  Install bumper cover (front) → Rep. Gr.63. Tightening torques

Component	Nm
Camshaft sprocket to hub	25
Tensioning roller for toothed belt to cylinder head	20 + 45°
Toothed belt cover (bottom) to cylinder block	10 1)
Toothed belt cover (centre) to cylinder block	10 1)
l  1) Apply locking fluid when installing; refer to → Electronic parts catalogue for locking fluid.