Variable Valve Timing Solenoid: Service and Repair

WM 155519 Removing and installing solenoid/hydraulic valve for valve lift switchover

Preliminary work

Information

Guided Fault Finding using the PIWIS Tester as well as the DME short test "Valve lift" must be performed before replacing the hydraulic valve. This is essential in order to avoid replacing the hydraulic valve unnecessarily.

The hydraulic valves lie on the rear side of the cylinder heads facing the plenum panel (under vacuum pump and fuel high-pressure pump).

Cylinder bank 1 to 4 =>
1. Remove vacuum pump. -> 477619 Removing and installing vacuum pump Service and Repair

Cylinder bank 5 to 8 =>
2. Remove high-pressure pump. -> 246319 Removing and installing high-pressure pump 246319 Removing and installing high-pressure pump

Removing hydraulic valve for valve lift switchover

1. Pull off cable plug for hydraulic valve and remove both screws.





Camshafts, cylinder bank 1 to 4









Camshafts, cylinders 5 to 8





2. Pull hydraulic valve out of cylinder head. Make sure that the sealing ring is also removed. If it is not, look for the sealing ring using a mirror and a torch.
3. Clean front strainer of hydraulic valve with solvent naphtha. Replace the hydraulic valve if damaged or heavily soiled.

Installing hydraulic valve for valve lift switchover

Information

- The tightening specifications for the basic engine are stored centrally. -> 1001IN Tightening torques, tightening sequences, assembly overviews [1][2]Specifications. Tightening torques and assembly instructions for other assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.

Cylinder bank 1 to 4:
1. Install hydraulic valve -4- with new sealing ring in correct position.
Sealing ring must not slip out of place. Fit and tighten screws -3-.





Camshafts, cylinder bank 1 to 4





Cylinder bank 5 to 8:
2. Install hydraulic valve -4- with new sealing ring in correct position.
Sealing ring must not slip out of place. Fit and tighten screws -5-.





Camshafts, cylinder bank 5 to 8





3. Connect cable plug for hydraulic valve.

Subsequent work

Cylinder bank 1 to 4 =>
1. Install vacuum pump. -> 477619 Removing and installing vacuum pump Service and Repair

Cylinder bank 5 to 8 =>
2. Install high-pressure pump. -> 246319 Removing and installing high-pressure pump 246319 Removing and installing high-pressure pump