Removing and Installing Cylinder Head

Removing and installing cylinder head on V6 DFI engines





Preliminary work

1. Remove belt tensioner.

Pfeile - Cheese head bolts on belt tensioner





Belt tensioner

2. Release the engine wire harness around the cylinder head.
3. Remove bar ignition modules.
4. Remove intake-air distributor.
5. Remove cylinder head cover (valve cover.
6. Remove upper timing-case cover.
7. Set cylinder 1 to compression TDC.
8. Remove the timing chain from the camshaft controllers and put it to one side.

Removing cylinder head

Warning:
Danger of injury and crushing!
^ Risk of injury when lifting the cylinder head.

-> Wear suitable protective gear (e.g. gloves).

Information:
^ If more extensive work was carried out, e.g. if the cylinder head was replaced, the exhaust manifolds, fuel injectors, fuel distributor pipe, combination valve, timing chain housing and various small parts must also be modified.

1. Remove cylinder head. Loosen the screws one after the other in the opposite sequence to the sequence shown, i.e. start at cylinder-head screw 20 and loosen cylinder-head screw 1 last.





Cylinder head

1-6 - Pistons of cylinders 1 - 6
20-1- Loosening sequence for cylinder-head screws

Installing cylinder head

Caution:
Leaks due to components being at too low a temperature or at different temperatures!
^ If components that are cold or at different temperatures are sealed together by the application of sealant, adhesion problems and leaks can arise due to the build-up of condensation water or component distortion.

-> Components must have reached at least 17°C. throughout.

-> Components must not be too hot (distortion).

-> Spare parts that are stored in the cold or heat (strong sunlight), must be brought to room temperature or the same temperature as other parts before installation.

1. Install cylinder head.





Cylinder head

1-6 - Pistons of cylinders 1 - 6
1 - - Tightening sequence for cylinder-head screws -> Initial tightening: 15 Nm (11 ftlb.) -> Tightening 20 torque: 30 Nm (22 ftlb.) -> Torque angle: 180°

Information:
^ It is best to use only a spatula and acetone to clean the sealing faces. Ensure good ventilation because of the acetone!
^ Use a cleaning cloth to wipe the sealing faces clean and remove any grease.
^ Replace the cylinder-head gasket.
^ Replace the cylinder-head screws with new ones.

1.1. Thoroughly clean all sealing faces before assembly.
1.2. Cylinder head gasket must always be replaced.
1.3. Always observe tightening sequence (1-20) for cylinder-head screws -1 to 20- and tighten to the specified torque.
1.3.1. Tighten cylinder-head screws to an initial tightening torque of 15 Nm (11 ftlb.).
1.3.2. Tighten cylinder-head screws to 30 Nm (22 ftlb.).
1.3.3. Then tighten all cylinder-head screws a second time to 30 Nm (22 ftlb.).
1.3.4. And finally, tighten the cylinder-head screws to a torque angle of 180°.

Subsequent work

1. Fit timing chains.





Component overview of timing chains

1 - Timing chain housing
2 - Oval-head screw on timing chain housing -> Tightening torque: 8 Nm (6 ftlb.)
3 - Timing chain
4 - Outlet camshaft controller (marking 32 A)
5 - Sealing ring
6 - Oil pump
7 - Fastening screw on oil pump -> Tightening torque: 8 Nm (6 ftlb.)
8 - Tensioning rail
9 - Chain tensioner on timing chain -> Tightening torque: 40 Nm (30 ftlb.)
10 - Sealing ring (A22 x 27), always replace
11 - Bearing pin on guide rail -> Tightening torque: 10 Nm (7.5 ftlb.)
12 - Sprocket
13 - Drive wheel for timing chain
14 - Hexagon-head bolt -> Initial tightening: 60 Nm (44 ftlb.) -> Torque angle: 90°
15 - Chain tensioner for drive chain
16 - Drive gearwheel for drive chain
17 - Drive chain
18 - Guide rail for drive chain
19 - Bolt for guide rail -> Tightening torque: 10 Nm (7.5 ftlb.)
20 - Fastening screw on guide rail -> Tightening torque: 20 Nm (15 ftlb.)
21 - Hexagon-head bolt on guide rail -> Tightening torque: 23 Nm (17 ftlb.)
22 - Hexagon-head bolts on camshaft controllers -> Initial tightening: 60 Nm (44 ftlb.) Torque angle: 90°
23 - Guide rail for timing chain
24 - Drive gearwheel for high-pressure pump
25 - Intake camshaft controller (marking 24 E)
26 - Valve for outlet camshaft controller
27 - Valve for intake camshaft controller
28 - Guide rail

1.1. Install chain tensioner.

Caution:
Damage to engine by turning crankshaft against the rotation direction of the engine (engine assembled)!

-> Never rotate crankshaft against the operating direction if the timing drive mechanism is mounted (timing chain jumps over).

-> Proceed carefully while working as otherwise the engine can be damaged.

-> Always turn the engine on the crankshaft and never on the camshaft as the timing chain may jump over.

-> After working on the camshaft wheels, the timing must be set.

-> Please observe general warning notes and working regulations.

2. Check the timing.
3. Fit upper timing-case cover.

1 - Drive shaft
2 - Upper timing-case cover
3 - Oval-head screw -> Tightening torque: 8 Nm (6 ftlb.)
4 - Oval-head screw on vacuum pump -> Tightening torque: 8 Nm (6 ftlb.)
6 - Seal
7 - Sealing ring





Removing and installing vacuum pump

4. Install cylinder head cover.





Removing and installing valve cover seal

1 - Cylinder head cover
2 -Cylinder head cover gasket (valve cover seal)
3 - Fastening screw on cylinder head cover -> Tightening torque: 10 Nm (7.5 ftlb.)
4 - Cover

5. Install belt tensioner.

Pfeile - Cheese head bolts on belt tensioner -> Tightening torque: 25 Nm (19 ftlb.)





Belt tensioner

6. Fit and tension the drive belt.





Fitting sequence

1 - Crankshaft vibration balancer
2 - Coolant pump
3 - Drive belt tensioning roller
4 - Air conditioning compressor
5 - Power-steering pump/tandem pump
6 - Generator
7 - Deflection roller

7. Install intake-air distributor.
8. Install bar ignition modules.
9. Install engine wire harness.