Removing and installing toothed belt, engine code AHH — AUDI

AFF AFN AHH AHU AVG
Special tools,
testers and auxiliary items required

Special tool 2065 A
Special tool 3036
Special tool 3359
Special tool Matra V/159

Engine in vehicle
Lock carrier must be in service position => Page
13-1
.

Removing

Remove engine cover panel -arrows-.
Removing toothed belt => Page
13-19
Remove viscous fan (with belt pulley) => Page
13-13
.
Install ribbed belt tensioner => Page
13-7
.

Remove bolts -3- and detach cover -2-.
Place solenoid valve for boost pressure control-1- to one side with hoses connected.

Unbolt vibration damper.

Remove upper and bottom section of toothed belt guard -arrows-.

Turn crankshaft to TDC No. 1 cylinder -arrow- (vehicles with manual gearbox).

Turn crankshaft to TDC No. 1 cylinder -arrow- (vehicles with automatic gearbox).

Note:

With engine removed turn crankshaft to TDC No. 1 cylinder=> Page
13-59
.

Remove cylinder head cover => Page
15-8
.

Lock camshaft with setting bar 2065 A.
Align setting bar as follows:
Turn arrested camshaft so that one end of setting bar contacts cylinder head. Measure the gap at other end of setting bar using a feeler gauge. Place a feeler gauge corresponding to half the gap between setting bar and cylinder head. Turn camshaft until setting bar contacts feeler gauge. Insert a 2nd feeler gauge of same thickness at other end, between setting bar and the cylinder head.

Lock injection pump sprocket with setting pin 3359.
Remove securing bolts -arrows- of injection pump sprocket.

Note:

Do not loosen central nut -2- of injection pump sprocket. Otherwise the injection pump basic setting is maladjusted and can no longer be corrected using workshop tools.

Mark direction of rotation of belt with chalk or felt pen.
Remove tensioner.
Remove idler wheel.
Take off toothed belt.

Installing (adjust valve timing)

Camshaft locked with setting bar.
Injection pump locked with setting pin 3359.

Notes:

The position of the toothed belt must be set as described below, even after repairs in which the belt is only taken off the camshaft sprocket.
When turning the camshaft, the crankshaft must not be at TDC at any cylinder. Danger of damage valves/piston crown.
Never use setting bar to counterhold when loosening and tightening camshaft sprocket. Counterhold with 3036.

Replace securing bolts -1- of injection pump sprocket.

Loosen securing bolt of camshaft sprocket by 1/2 turn. Release camshaft sprocket from camshaft taper by tapping with a hammer (using a drift through hole of rear toothed belt guard).
Centre the injection pump sprocket in the slots.
Check again whether TDC mark on flywheel and reference mark are aligned.
Place toothed belt on crankshaft sprocket, intermediate shaft, injection pump sprocket and tensioner (note direction of rotation).
Install camshaft sprocket together with toothed belt and position with securing bolt (camshaft sprocket can still be turned).
Install the idler wheel.

Turn tensioner eccentric clockwise using nut driver (e.g. Matra V/159) until notch and lobe -arrows- are aligned.

Note:

If eccentric has been turned too far clockwise during tensioning, tensioner must then be fully released. Then turn eccentric clockwise again to tension.

Tighten lock nut on tensioner to 20 Nm.
Check again whether TDC mark on flywheel and reference mark are aligned.
Tighten securing bolt for camshaft sprocket to 45 Nm.

Note:

Never use setting bar to counterhold when loosening and tightening camshaft sprocket. Counterhold with 3036.

Tighten new securing bolts for injection pump sprocket initially to 20 Nm.

Notes:

After injection start dynamic test, bolts must be tightened by a 1/4 (90°) turn.
The securing bolts are stretch bolts and cannot be re-used. Once tightened to correct torque (20 Nm + 90°), they must be replaced after loosening.

Remove setting bar 2065 A from camshaft and setting pin 3359 from injection pump sprocket.

Turn crankshaft a further two rotations in direction of engine rotation and reset to TDC No. 1 cylinder.

Check tension of toothed belt.
Markings -arrows- must be aligned.

If necessary retighten toothed belt.
Check if injection pump sprocket can be locked with pin 3359.
Check position of camshaft with setting bar 2065 A.

Notes:

If it is not possible to insert setting bar, repeat adjustment.

If setting pin 3359 cannot be inserted:

Loosen securing bolts -arrows- of injection pump sprocket.
Rotate injection pump sprocket hub until setting pin fits.
Retighten securing bolts for injection pump sprocket to 20 Nm.

Install viscous fan=> Page
13-13
.

Install ribbed belt =>Page
13-20
.
Dynamically check commencement of injection

=> Diesel direction-injection and glow lamp system (4-cyl.) 07.97 ä; Repair group 23; Servicing diesel direct injection system; Dynamically checking and adjusting commencement of injection
Diesel direction-injection and glow lamp system (4-cyl.) 07.97 ä
Servicing diesel direct injection system
Dynamically checking and adjusting commencement of injection

Tightening torques

Component · Nm
Toothed belt sprocket to camshaft · 45
Idler wheel to bracket · 25
Semi automatic tensioner to cylinder block · / 20
Bottom section of toothed belt guard to cylinder block · / 10
Vibration damper · 8.8 · 25
to crankshaft · 10.9 · 35
Tensioner for ribbed belt to bracket for alternator, vane pump and viscous fan · / / 45
Injection pump toothed belt sprocket to injection pump hub · / 20 + 90°1)2)

1)
Stretch bolts - renew

2)
90°corresponds to a quarter turn