Audi Workshop Service and Repair Manuals

Removing toothed belt from camshaft sprockets

Special tools and workshop equipment required

t	Locking pin -T40011-

t	Counter-hold tool -3036-

t	Socket (22 mm) -3078-

t	Locking pin -3242-

t	Diesel injection pump locking pin -3359-

t	Camshaft holder -3458-

t  Two-arm puller -T40001-

Removing l  Engine in vehicle. l  Lock carrier must be in service position → Chapter. –  Open oil filler cap. –  Turn engine until the marking “- OT -” (TDC) is visible on camshaft.   Note Turn over the engine at the central bolt on the crankshaft. –  Unscrew plug for TDC marking from cylinder block.   Note There is a TDC drilling in the crankshaft directly behind the plug (it is possible to feel the hole).   WARNING Injury risk. Do not rotate the crankshaft while feeling for the TDC drilling with your finger.

–  Screw locking pin -3242- into threaded hole where plug has been removed, and tighten.

–  Unbolt coolant expansion tank -arrows 1-. –  Detach wire for coolant shortage indicator switch -F66- and move coolant expansion tank to one side with coolant hoses -2- attached.

–  Remove bolts -1- for exhauster pump with heat shield on cylinder head (left-side) and turn pump in anti-clockwise direction -arrow-. –  Move exhauster pump clear to the rear (leave hose attached).

–  Slacken hose clip -3-. –  Unplug connector -4-. –  Pull hose -2- off air cleaner housing. –  Unscrew bolt -1- and remove air cleaner housing. –  Unfasten clamping nut for fuel filter and lift filter out of retainer. –  Disengage fuel lines at retainer and move fuel filter to side with lines connected.

–  Remove air intake pipe between turbocharger and charge air cooler (right-side) -arrows-.

–  Using a screwdriver, lever off sealing cap -arrow- on cylinder head (right-side).   Note t  Removal destroys sealing cap. t  Take care not to damage sealing surfaces.

–  Insert camshaft holder -3458- in both cylinder heads and secure them with chain to prevent them from falling.   Caution Do not use camshaft holders -3458- as counterhold tools.

Caution If a used belt runs in the opposite direction when it is refitted, this can cause breakage. Before removing, mark direction of rotation of toothed belt with chalk or felt-tipped pen for re-installation. –  Slacken toothed belt tensioner and take toothed belt off camshaft sprocket.

–  Unbolt drive sprocket -1- for injection pump from camshaft sprocket -arrows-.   Caution Do not use camshaft holder -3458- as a counterhold tool.

–  Loosen bolts for camshaft sprockets using counter-hold tool -3036-.   Note Leave bolts screwed in loosely. –  Detach cover cap at bottom right of bracket for viscous fan.

–  Turn toothed belt tensioning roller in anti-clockwise direction -arrow- using an 8 mm hexagon key until tensioning lever of tensioner is compressed far enough to allow locking pin -T40011- to be inserted into hole and plunger.   Note The toothed belt tensioner is oil-damped and can therefore only be compressed slowly by applying constant pressure.

Caution If a used belt runs in the opposite direction when it is refitted, this can cause breakage. Before removing, mark direction of rotation of toothed belt with chalk or felt-tipped pen for re-installation. –  Pull camshaft sprockets (left and right) off their tapers using two-arm puller -T40001- with claws -T40001/2-. –  Unbolt camshaft sprocket, left-side (cylinder bank 2). –  Detach toothed belt from camshaft sprockets. Installing (adjusting valve timing) l  Camshafts locked in position with camshaft holders -3458-. l  Crankshaft locked in position with locking pin -3242-. l  Camshaft sprockets free to turn. The valve timing must be adjusted as described below, even when the toothed belt has only been removed from the camshaft sprocket: l  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. l  Do not use camshaft holders -3458- as counterhold tools. l  Adjustment can be performed with cold or warm engine.

–  Fit the toothed belt onto one of the camshaft sprockets. –  Take second camshaft sprocket, fit toothed belt and install sprocket on camshaft. –  Tighten the two camshaft sprocket bolts until the sprockets can still just be turned without axial movement.

–  Use an 8 mm hexagon key to slacken toothed belt tensioning roller in anti-clockwise direction -arrow- and pull out locking pin -T40011-.

–  Use torque wrench to pretension toothed belt to 15 Nm in clockwise direction -arrow-.

–  Tighten bolts for camshaft sprockets using counter-hold tool -3036-.   Caution Do not use camshaft holders -3458- as counterhold tools.

–  Lock injection pump sprocket with diesel injection pump locking pin -3359-.

–  Install drive sprocket for injection pump -1- so that it is aligned centrally in elongated holes. –  Tighten drive sprocket -arrows- until it is still just possible to turn it on the camshaft sprocket. –  Position toothed belt for injection pump. Pay attention to the direction of rotation as marked upon removal.

–  Tension toothed belt by turning Allen key in anti-clockwise direction -arrow- until marks -1- coincide. –  Then tighten nut using socket (22 mm) -3078-.   Note Depending on version, pointer -1- may have no tip. –  Tighten bolts at camshaft sprocket. –  Remove diesel injection pump locking pin -3359-. –  Remove camshaft holders -3458- from both cylinder heads. –  Remove locking pin -3242-. –  Turn crankshaft two rotations in normal direction of rotation until the crankshaft is at “TDC” again.

–  To check adjustment, screw locking pin -3242- into hole in cylinder block once again.

–  Check positions of camshafts with camshaft holders -3458-. If it is not possible to insert camshaft holders, repeat adjustment. –  Remove camshaft holders -3458- from both cylinder heads. –  Remove locking pin -3242-.

–  Check tension of toothed belt for injection pump. l  Marks -1- and -2- must be opposite one another. –  Screw plug for the TDC mark into cylinder block with a new seal. –  Install exhauster pump with new O-rings on cylinder head (left-side).

–  Renew sealing cap (rear) on cylinder head (right-side). –  Using a suitable drift, knock in new sealing cap (core plug) -arrow- until flush. Remaining installation steps are carried out in reverse sequence; note the following:   Note Renew seals and O-rings. –  Dynamically check and adjust commencement of injection → Rep. Gr.23. Tightening torques

Component	Nm
Camshaft sprocket to camshaft	75
Drive sprocket for injection pump to camshaft	22
Exhauster pump to cylinder head	10
Screw plug in cylinder block	10
Tensioning roller for injection-pump toothed belt to bracket for viscous fan	36