Variable Valve Timing Actuator: Testing and Inspection
Variable valve timing unit, checking and adjusting
Special tools:
999 5451 ADJUSTMENT TOOL 999 5451 Adjustment Tool
999 5456 COMPRESSION TOOL 999 5456 Compression Tool
999 5452 CAMSHAFT ADJUSTMENT TOOL 999 5452 Camshaft Adjustment Tool
Note! The illustrations in this service information are used for different model years and/or models. Some variation may occur. However, the essential information in the illustrations is always correct.
Installing and adjusting the variable valve timing unit/gear pulley on the camshafts.
Note! This procedure must be carried out with precision as any deviation could generate a fault symptom.
Installing the crankshaft adjustment tool
Remove the starter motor mounting screws. Pull out the starter motor and put it aside.
Remove the blind cover plug from the hole for the adjustment tool.
Turn the crankshaft clockwise slightly.
Install: 999 5451 ADJUSTMENT TOOL 999 5451 Adjustment Tool. Ensure that the tool bottoms out against the cylinder block.
Installing the variable valve timing (VVT) unit on the camshaft
Note! Oil the center screw before installation
Push on the variable valve timing unit/timing gear pulley on the camshaft.
Install the center screw (1) which secures the variable valve timing unit to the camshaft.
Tighten the screw slightly.
Slacken off, but do not remove the screws (2) which secure the timing gear pulley to the variable valve timing unit.
Turn the timing gear pulley until the screws at the oval holes are in the center position. Tighten the screws (2) slightly.
Turn the variable valve timing unit clockwise to its limit position so that the unit is in its end position. Install the upper timing cover.
Slacken off the center screw and continue turning clockwise until the timing gear pulley marking aligns with the marking on the upper timing cover.
Tighten the center screw in the variable valve timing unit. Tighten. See: Tightening torque Tightening Torque.
Installing the timing gear pulley on the exhaust camshaft
Install:
- the timing gear pulley on the exhaust camshaft. Turn until the timing gear pulley marking aligns with the marking on the upper timing cover.
- the 3 screws. Do not tighten.
Checking the tensioner and idler pulleys
Spin the pulleys and listen for noise from the bearings.
Check that the pulley surfaces to the belt are clean and smooth.
Check the tension pulley lever and mounting.
The tension pulley lever, torque 30 Nm. The idler pulley, torque 25 Nm.
Installing the tensioner/damping unit
Check that there is no visible leakage.
Press the tensioner/damping unit together using: 999 5456 COMPRESSION TOOL 999 5456 Compression Tool.
Position the tensioner/damping unit in the tool. Screw the tool center nut to the bottom.
Wait until it is compressed and then install a lock pin in the piston.
Note! The tensioner damping unit must be replaced if there is leakage or there is no resistance when pushed in or if it cannot be pushed in.
Install the tensioner/damping unit. Tighten to 25 Nm.
Installing the timing belt
Note! Variable valve timing units do not have return springs and are easily thrown out of position when the camshaft belt is installed. Check that the markings align.
Install the belt in the following order:
- the idler pulley
- intake cam
- exhaust cam
- water pump
- tension pulley.
Tensioning of cambelt
Pull the lock pin out of the tensioner/damping unit.
Caution! Optimize the timing belt tension. Press it between the camshaft timing gear pulleys and between the water pump and exhaust camshaft.
Tightening
Slacken off the 3 timing gear pulley screws slightly (applies to both timing gear pulleys).
Install the center plug in the variable valve timing unit.
Tighten, see: Tightening torque Tightening Torque.
Hold the center plug at 35 Nm at the same time as tightening the 3 x screws on the camshaft timing gear pulley to: Tightening torque Tightening Torque.
This is to ensure that the variable valve timing unit is in its end position when the timing gear pulley is tightened.
Tighten the 3 x screws on the exhaust camshaft timing gear pulley. Tighten to: Tightening torque Tightening Torque
Remove:
- 999 5452 CAMSHAFT ADJUSTMENT TOOL 999 5452 Camshaft Adjustment Tool from the rear of the camshafts
- 999 5451 ADJUSTMENT TOOL 999 5451 Adjustment Tool. Install new plugs with new sealing washers. Tighten. See: Tightening torque Tightening Torque.
Install the deflection limiter washer on the piston rod for the tensioner/damping unit.
Checking the markings and belt tension
Position the upper timing cover.
Turn the crankshaft 2 rotations. Check that the markings on the crankshaft and timing gear pulleys correspond.
Remove the upper timing cover.