Audi A3 Workshop Service and Auto Repair Manuals

Removing and installing toothed belt - vehicles with large engine support   Note

The engine support does not have to be removed in order to remove the toothed belt on vehicles with large engine support -2-.

Special tools and workshop equipment required

t	Diesel injection pump locking pin -3359- (2x)

t	Locking pin -T10060 A-

t	Crankshaft stop -T10050- for engines with circular crankshaft sprocket

t	Crankshaft stop -T10100- for engines with oval crankshaft sprocket

t	Counter-hold tool -T10172- with pin -T10172/4-

t	Special wrench, long reach -T10264-

t  Locking tool -T10265- t  Locking fluid → Electronic parts catalogue

Removing –  Lift off engine cover panel (outside -1- and inside -2-) by pulling up evenly.

Caution Rules for cleanliness when working on the injection system → Chapter.   WARNING t  In extreme cases the fuel lines and the fuel can reach a temperature of 100 °C on vehicles with unit injector engine. Allow the fuel to cool down before disconnecting the lines - danger of scalding. t  Wear protective gloves. t  Wear safety goggles. –  Disconnect fuel supply pipe -2- and fuel return pipe -1- by pulling release tabs.

–  Disconnect fuel supply pipe -2- and fuel return pipe -1- from fuel lines.

Fuel filter - version 1: –  Pull fuel filter with hoses attached upwards out of the bracket -arrow-.

Fuel filter - version 2: –  Slacken bolt -1- one turn. –  Remove bolt -2- and nut -3-. –  Remove fuel filter with hoses attached.

All vehicles (continued): –  Unscrew bracket -3- for fuel filter. –  Unscrew bolt at filler neck -2- for washer fluid reservoir. –  Unscrew coolant expansion tank -1- and move clear to one side with the lines attached.   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.

–  Lock poly V-belt tensioner using locking pin -T10060 A-. –  Remove poly V-belt.

–  Remove tensioner for poly V-belt -arrows-.

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

–  Remove centre noise insulation -fasteners 1 ... 3-.

–  Remove noise insulation (right-side) -fasteners 1 ... 3-.

–  If fitted, remove bolts -1- and -2-. –  Remove air pipe (right-side) by lifting retaining clips -arrows- slightly.

–  Remove cover cap for vibration damper. –  Unbolt vibration damper; counterhold on centre bolt with ring spanner.

–  Unbolt toothed belt covers (bottom and centre) -arrows-.

Caution The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise). –  Turn the crankshaft to TDC for cylinder No. 1.   Note At TDC position the toothed segments -arrows- face upwards. –  Lock hubs with locking pins -3359-.

–  Lock crankshaft sprocket using crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket. l  The markings on the toothed belt sprocket and the crankshaft stop must align -arrow-. The pin of the crankshaft stop must engage in the aperture in the sealing flange.   Note The crankshaft stop can only be pushed onto the sprocket from the front face of the teeth.

–  Mark direction of rotation of toothed belt with chalk or felt pen. –  Loosen the bolts -arrows- for camshaft sprockets approx. 2 turns.

–  Loosen securing nut -1- for tensioning roller. –  Turn eccentric adjuster of tensioning roller anti-clockwise -arrow- using special wrench, long reach -T10264- until tensioning roller can be secured with locking tool -T10265-.

–  Now turn eccentric adjuster of tensioning roller 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  Camshafts locked with locking pin -3359- (2x). l  Crankshaft is locked using crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket. l  Tensioning roller locked with locking tool -T10265- 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 sprockets on the hubs without axial movement. –  Turn the camshaft sprockets in their elongated holes clockwise until the stop. –  Fit the toothed belt to crankshaft, tensioning roller, camshaft sprockets, idler roller and finally to sprocket for coolant pump.

–  Adjust toothed belt tension as follows: –  Remove locking tool -T10265- from tensioning roller. –  Loosen securing nut -1- for tensioning roller. –  Turn eccentric adjuster of tensioning roller clockwise -arrow- using special wrench, long reach -T10264- until pointer -2- aligns with the centre of the slot on the base plate.   Note Make sure that the securing nut -1- on the tensioning roller does not turn at the same time. –  Hold tensioning roller in this position and tighten securing nut -1- on tensioning roller to 20 Nm + 45° (1/8 turn).   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.

–  Attach counter-hold tool -T10172- as shown in illustration and apply tension to driving section of toothed belt by pressing in direction of -arrow-. –  Tighten camshaft sprocket securing bolts -arrows- to 25 Nm. –  Remove locking pins and crankshaft stop.

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 -A- into place with the locking pin -3359- when turning. –  Check whether: t  The hub -B- can be locked with the locking pin -3359-; t  The crankshaft can be locked with the crankshaft stop. t  The tensioner pointer is centred or a maximum of 5 mm to the right of the slot in the base plate.

Adjusting the valve timing: If hub -B- cannot be locked: –  Loosen securing bolts -2- for inlet camshaft sprocket. –  Place a ring spanner on the centre bolt for inlet camshaft. –  Turn hub until locking pin -3359- can be inserted. –  Tighten bolts -2- for inlet camshaft sprocket to 25 Nm. –  Remove locking pins and crankshaft stop.   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.

If the crankshaft cannot be locked: –  Loosen bolts -1- and -2- for the camshaft sprockets -A- and -B-. –  Continue to turn the crankshaft in the normal direction of rotation until it can be locked with crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket.   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 bolts -1- and -2- for camshaft sprockets -A- and -B- to 25 Nm. –  Remove locking pins and crankshaft stop.   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. –  Install vibration damper → Chapter. –  Install poly V-belt → Chapter. –  Adhere to the instructions for installing air pipes and hoses with plug-in connectors → Chapter. Tightening torques

Component	Nm
Tensioning roller for toothed belt to cylinder head	20 + 45° 1)
Camshaft sprocket to hub	25
Toothed belt cover (bottom) to cylinder block	10 2)
Toothed belt cover (centre) to cylinder block	10 2)
Tensioner for poly V-belt to bracket for ancillaries	23
l  1) 45° = one eighth turn. l  2) Apply locking fluid when installing; refer to → Electronic parts catalogue for locking fluid.