Overhaul

Removing and installing hydraulic valve for valve lift switchover (variable valve lift adjustment)

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.

Cylinder bank 5 to 8

2. Remove high-pressure pump.

Removing hydraulic valve for valve lift switchover (variable valve lift adjustment)

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

1 - Camshaft (outlet)
2 - Camshaft (intake)
3 - Hydraulic valve for variable valve lift control
4 - Screw, M5 x 12
5 - Switching tappet (oil with engine oil)
6 - Bucket tappet (oil with engine oil)
7 - Stopper
8 - Mounting saddle 1 to 4
9 - Stopper
10 - Bearing locations (oil with engine oil)
A - Direction of travel

Camshafts, cylinders 5 to 8

1 - Switching tappet (oil with engine oil)
2 - Bucket tappet (oil with engine oil)
3 - Camshaft (intake)
4 - Hydraulic valve for variable valve lift control
5 - Screw, M5 x 12
6 - Camshaft (outlet)
7 - Stopper
8 - Mounting saddle, cylinders 5 to 8
9 - Stopper
10 - Bearing surfaces (oil with engine oil)
A - Direction of travel

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 (variable valve lift adjustment)

Installing hydraulic valve for valve lift switchover

1. Install hydraulic valve with new sealing ring in correct position. Sealing ring must not slip out of place. Position screws and tighten.

Camshafts, cylinder bank 1 to 4

1 - Camshaft (outlet)
2 - Camshaft (intake)
3 - Hydraulic valve for variable valve lift control
4 - Screw, M5 x 12 - Tightening torque: 6 Nm (4.5 ftlb.)
5 - Switching tappet (oil with engine oil)
6 - Bucket tappet (oil with engine oil)
7 - Stopper
8 - Mounting saddle 1 to 4
9 - Stopper
10 - Bearing locations (oil with engine oil)
A - Direction of travel