Basic information about 6- and 8-cylinder engines (Audi A4 B6)

The engines have three intake and two exhaust valves per cylinder. Each bank of engine cylinders has two camshafts. In the V6 engine, the exhaust camshafts are driven by a toothed belt, the intake camshafts are driven by a chain from the exhaust camshafts. In the V8 engine, four camshafts, as well as auxiliary units, are driven by several chains. The drive chains are located on the flywheel side (checkpoint side).

Cylinder block, crankshaft and flywheel of a V6 engine

1 — Crankshaft

Checking axial play:

New: 0.07-0.23 mm
Wear limit: 0.25 mm
Radial clearance check using Plastigage: 0.018 - 0.045 mm
Wear limit: 0.10 mm

Attention: When checking the radial clearance, do not rotate the crankshaft.

2 — Main bearing cap 4 with recess for thrust washer
3 - Bolt. Replace, 60 Nm+90°. To measure the radial clearance, tighten the bolt with a force of no more than 60Nm
4 — Main bearing thrust washer 4
5 — Flywheel/Drive Disc
6 - Flywheel/drive plate bolt. Replace, (flywheel 60Nm+180°), (drive disk 60 Nm+90°). When giving up, use tool 3242 to lock the crankshaft
7 — Main bearing shells. Do not mix up the removed shells
8 — Sealed flange with seal. Replaced as an assembly. Drain coolant before removing
9 — Gasket. Replace
10 - Bolt, 10 Nm
11 — Cylinder block thrust washer, bearing 4
12 - Bolt, 25 Nm. Pre-tighten by hand before tightening the main bearing cap bolts
13 — Cylinder block
14 — Guide bushing

Main elements of the V6 engine timing drive

1 - Bolt, 55 Nm
2 — Timing belt tensioner. Before removing, lock with tool 3204
3 - Upper right timing belt cover
4 - Center right timing belt cover
5 — Toothed belt. Before removing, mark the direction of the belt. Check for wear. Do not bend
6 - Upper left timing belt cover
7, 8 - Bolt, 25 Nm
9 — Washer
10 — Bearing bushing
11 — Timing belt tension roller
12 — Tension lever
13 — Sealing ring
14 - Bolt, 25 Nm
15 — Bracket
16 - Connection (thermostat housing)
17 - Water pump
18 — Oil pump
19 — Cylinder head
20 — Crankcase breather housing
21 — Cylinder block
22 - Bolt, 45 Nm
23 — Bracket
24 — Oil pan
25 — Guide roller
26 - Bolt, 45 Nm
27 — Crankshaft gear
28 - Bolt 200 Nm+180°, replace
29 — Belt tensioner
30 - Bolt, 10 Nm. Install with D6 grease
31 — Fan pulley
32 — Bolt M8 - 25 Nm, M6 - 10 Nm
33 — Timing belt cover
34 - Bolt, 10 Nm
35 — Torsional vibration damper
36 - Bolt, 25 Nm

Chain drive intake camshaft. V6 engine

1 - Upper right timing belt cover
2 - Center right timing belt cover
3 - Upper left timing belt cover
4 - Hex nut, 10 Nm
5 - Rear timing belt cover
6 - Lifting eye
7 - Bolt, 25 Nm
8 — Cylinder head cover gasket. Replace if damaged. Before installation, lubricate the gasket surface between the bearing cover and the cylinder head with D 454 300 A3 grease
9 — Cylinder head cover
10 — Gasket
11 — Cover. If damaged, replace the gasket
12 — Bracket
13 - Hex nut, 10 Nm. Tighten from the center outward
14 — Cylinder head bolt. Replace
15 — Cylinder head. Check flatness
16 — Oil deflector
17 — Cylinder head gasket (metal). Replace
18 — Crankshaft gear
19 — Clamping plate
20 - Bolt, 55 Nm

Cylinder head components. V6 engine

1 - Double bearing cap. Lightly lubricate the mating surface with AV 174 004 01 grease
2 - Bolt, 10 Nm
3 — Camshaft bearing covers for exhaust valves. Lightly lubricate the mating surfaces of the extreme (outer) bearings with AV 174 004 01 grease
4 — Exhaust camshaft. Checking radial clearance using Plastigage:

Runout, no more than: 0.01 mm
Wear limit: 0.10 mm

5 — Cap. Replace. To remove, remove the bearing cap. With the bearing cap installed, press on using tool 3202 and a plastic hammer
6 — Intake camshaft bearing caps
7 — Exhaust camshaft
8 — Camshaft adjuster. Before removing, lock with chain tensioner lock 3366. Check camshaft adjustment
9 — Drive chain. Before removing, mark the direction of movement
10 - Bolt, 10Nm
11 — O-ring. Replace
12 — Valve 1 or 2 for adjusting the camshaft N₂05 or N₂08. Check the camshaft adjustment
13 — Gasket (rubber/metal). Replace
14 - Segment insert. Replace
15 — Hydraulic valve lifter. Do not interchange the lifters of different valves. Store with the contact surface with the camshaft cam down
16 - Split lock crackers
17 — Valve spring holder
18 — Valve spring
19 — Oil deflector cap
20 — Valve push rod
21 — Cylinder head
22 — Valves
23 — Seal. Lightly lubricate the seal lips
24 — CMP valve
25 - Conical washer
26 - Bolt, 25Nm
27 — Camshaft Position (CMP) Sensor
28 - Bolt, 10Nm
29 — Guide bushing