Audi Workshop Service and Repair Manuals

Detaching and re-fitting timing chain on camshafts Special tools and workshop equipment required

t  Camshaft bar -T10068 A- t  Sealing compound (black) → Electronic parts catalogue t  Sealing paste → Electronic parts catalogue Detaching camshaft timing chain l  Engine in vehicle. –  Drain off coolant → Chapter. –  Remove intake manifold → Rep. Gr.24.

–  Unplug electrical connector at coolant temperature sender -G62-.

–  Detach coolant hoses at the connections indicated -arrows-.

–  Remove bolts -arrows-. –  Pull bracket for coolant pipe for gearbox oil cooler to the left. –  Swing the bracket for secondary air hose forwards.

–  Remove bolt -arrow- on bracket for wiring harness.   Caution When removing the thermostat housing, push coolant pipe towards coolant pump with an assembly lever to prevent it from also being detached.

–  Remove thermostat housing -2-; when doing so, press the coolant pipe -1- towards the coolant pump with an assembly lever.

Vehicles with engine code letters BDB, BMJ, BUB: –  Disconnect hose -3- and vacuum hose -2- from combination valve for secondary air system. –  Disconnect coolant hose -1-.

Vehicles with engine code letters CBRA: –  Disconnect hose -1- and vacuum hose -2- from combination valve for secondary air system (left-side).   Note Ignore items marked -3- and -arrows-.

All vehicles (continued): –  Mark and unplug the electrical connectors: 1 -  Hall sender -G40- 2 -  Hall sender 2 -G163- 3 -  Inlet camshaft control valve 1 -N205- 4 -  Exhaust camshaft control valve 1 -N318- –  Unscrew cable guide from cover for camshaft timing chain.

–  Unscrew cylinder head cover bolts in the sequence -11 ... 1-.

–  Turn the crankshaft to the TDC marking -arrow- in the normal direction of rotation via the securing bolt on the vibration damper.

–  Cams -A- of cylinder 1 must face each other.

–  At the same time insert camshaft bar -T10068 A- in the slots on both camshafts; if necessary, turn the crankshaft 1 rotation further.

–  Unscrew chain tensioner for camshaft timing chain -arrow-.

–  Unscrew bolts -1 ... 3- and remove timing chain cover (top) from cylinder head horizontally. Take care not to damage the cylinder head gasket when removing.

–  Unscrew bolts -arrows- and remove guide rail -1-. –  Remove camshaft bar -T10068 A-.   Note The camshaft bar -T10068 A- must not be in place when loosening and tightening the securing bolts for the camshaft adjusters.

–  Unscrew the securing bolt at camshaft adjuster (inlet side); counterhold with open jaw spanner (32 mm) on hexagon flats of camshaft. –  Remove camshaft adjuster (inlet side).

–  Unscrew the securing bolt at camshaft adjuster (exhaust-side); counterhold with open jaw spanner (32 mm) on hexagon flats of camshaft. –  Remove camshaft adjuster (exhaust-side). –  Remove the camshaft timing chain over the camshaft control valves and set aside.

Fitting camshaft timing chain (adjusting valve timing) l  Tightening torques → Chapter, → Fig. and → Chapter. –  Install guide rail -1- and tighten bolts -arrows-.

–  Recheck TDC position of crankshaft -arrow-.

–  Check TDC position of camshafts: l  Cams -A- of cylinder 1 must face each other.

l  You should be able to insert the camshaft bar -T10068 A- in the slots in both camshafts.

–  If necessary, turn camshafts at hexagon flats -arrows- to correct position using a 32 mm open-end spanner.   Caution Avoid damage to valves and piston crowns. The crankshaft must not be at “TDC” at any cylinder when the camshafts are turned.

Note The two camshaft adjusters (marking 24E on inlet side and 32A on exhaust side) can only be secured to camshaft mounting in one position -arrows- (due to a dowel pin fitted).

–  First install the camshaft adjuster (inlet side): –  Turn sender wheel -1- clockwise -arrow- in camshaft adjuster as far as the stop.   Note The camshaft bar -T10068 A- must not be used as a counterhold tool.

–  Tighten the camshaft adjuster (inlet side) in this position to the inlet camshaft finger-tight. l  Contact surface of sender wheel at bolt head must be dry when installing. l  The marking “24E”-item 1- and the tooth just behind it must align with the notch -2- in the valve timing housing. Markings on valve timing housing → Fig. –  Lay the camshaft timing chain in this position tautly onto the chain sprocket of camshaft adjuster (inlet side).

–  Now count exactly 16 rollers on timing chain to the right starting at gear aligning with marking “24E”. Mark this roller with coloured pen.   Note The camshaft adjuster (exhaust side) is locked in “rest position”, so the sender wheel cannot be turned out of position when adjusting the valve timing. If the camshaft adjuster is not locked in “rest position”, turn adjuster by hand in both directions until it engages. If this is not possible, renew camshaft adjuster.

–  Fit camshaft adjuster (exhaust side) “32A” into camshaft roller chain with gear tooth at marking -1-, so that there are exactly the 16 counted rollers between marking “24E” and “32A” and the markings -1- and -2- align. –  It must be easily possible to attach camshaft adjuster (exhaust side) to camshaft (exhaust side) and to tighten it hand-tight.

–  Check again that both camshaft adjusters are positioned correctly.

–  Remove camshaft bar -T10068 A-. –  Tighten bolt at camshaft adjuster (inlet side); counterhold with open-end spanner on hexagon flats of camshaft.

–  Tighten bolt at camshaft adjuster (exhaust side); counterhold with open-end spanner on hexagon flats of camshaft.

Caution Prevent timing chain from slipping. When turning the crankshaft, it is necessary to press the tensioning rail firmly against the camshaft timing chain manually (to replace function of chain tensioner) -arrow-.

–  Turn crankshaft via the securing bolt for vibration damper 2 rotations in the normal direction of rotation until the marking is at TDC -arrow-.

–  Cams -A- of cylinder 1 must face each other.

You should then be able to insert the camshaft bar -T10068 A- in the slots in both camshafts. If the camshaft bar cannot be inserted: –  Repeat adjustment of valve timing.

–  Clean any old sealing compound from the 3 mm bores -arrows- in the cylinder head gasket. –  Fill the 3 mm bores in the cylinder head gasket with sealing compound (black) → Electronic parts catalogue.   Note With the cylinder head installed the holes in the cylinder head gasket are only half visible. –  Renew the oil seals in the upper cover for timing chains → Chapter. –  Clean sealing surfaces; they must be free of oil and grease.

–  Check if the dowel sleeves -2- and -3- are inserted in the upper cover for timing chains. –  Insert a new oil seal -1- and a new seal -4-. –  Thinly coat clean surface of upper cover for timing chains -hatched surface in illustration- with sealing paste → Electronic parts catalogue.   Note t  Also apply a thin coat of sealing paste to the surface beneath the cylinder head gasket (do not kink gasket). t  The upper cover for the timing chains must be installed within 5 minutes after applying the sealing paste.

–  Install upper cover for timing chains and tighten bolts in the following sequence: 1 -  Initially tighten bolts -1- and -2- to 5 Nm. 2 -  Tighten bolts -3- to 23 Nm. 3 -  Tighten bolts -1- and -2- to 10 Nm.

–  Secure chain tensioner -arrow- for camshaft timing chain. –  Turn the crankshaft 2 rotations in the normal direction of rotation and recheck valve timing. –  Install cylinder head cover → Chapter. –  Install intake manifold → Rep. Gr.24. –  Install thermostat housing → Chapter. 1)  Renew bolt. 2)  90° = a quarter of a turn.