Replacement W/Hydraulic Tensioner
Replacing timing belt
Special Tools: 998 8500, 999 5456
Remove:
- spark plug cover
- two fuel line clamps
- lift expansion tank and place over engine to one side
- front timing cover
- auxiliaries belt
Position camshafts/crankshaft according to marking
- Remove right front wheel and slacken off fender liner slightly.
- Remove vibration damper heat shield.
- The camshaft pulleys should rotate until all the markings are aligned.
Check measure the belt tension
Wait 5 minutes after aligning timing belt.
Position measuring instrument 998 8500 between the exhaust camshaft pulley and coolant pump.
Read the value using a mirror, the measuring instrument must not removed before the reading is taken.
- For 21 mm belts, the tension should be between 3.5-4.6 units.
- For the 23 mm belt the following applies:
B5204/B5254/B5234: 2.5-4.0 units
B5252: 2.7-4.2 units
Replace tensioner damping unit if the recommended values are NOT kept.
Removing timing belt
Hold tensioner damping unit upper screw
Slacken off the lower screw
Turn the tensioner damping unit so that the pulley comes free
Remove:
- lower screw
- tensioner damping unit
- upper timing cover
- timing belt
Greasing the bushing
Engines with automatic timing belt tensioners should have the lever bushing greased every time the belt is changed or the tension pulley removed. The lever arm must be greased so that the bearing does not stick and give the wrong tension.
Remove:
- Tension pulley lever screw
- Tension pulley
- Sleeve behind screw
Grease the surfaces on the lever bushing, the screw and the sleeve with grease P/N. 11 61 246-2 (50g) or 11 61 247-0 (500g).
Install:
- Sleeve
- Tension pulley
- Tension pulley lever screw
Torque tighten screw to 39 Nm ±5 Nm
Check tensioner and idler pulleys:
Spin the pulleys and listen for noise in the bearings.
Check that the tensioner pulley actuator arm has not seized in its bearing. Check the idler pulley and tensioner pulley are tightened correctly.
Pulley, tighten to: 30 Nm (22 ft lb)
Idler pulley, tighten to: 24 Nm (18 ft lb)
Adjusting the mechanical belt tensioner
If a mechanical belt tensioner is being used, adjust according to "Adjusting the Mechanical Belt Tensioner" Adjustments
Lock tensioner damping unit
Check there there is no visible leakage.
Compress tensioner with tools 939 5456. Position tensioner damping unit in the tool and screw tool center nut to the bottom. Wait until compression is complete and install a lock pin (2.0 mm) in the piston.
NOTE: If there is leakage or no resistance when pushed in or if it cannot be pushed in the tensioner damping unit must be replaced.
Install the new timing belt
Install tensioner damping unit torque to 25 Nm (18 ft lbs).
Place belt around the crankshaft and right idler pulley.
Place belt over camshaft pulley.
Place belt around coolant pump and press the belt over the tensioner pulley.
Installing camshaft pulley and timing belt
Caution! The timing belt must be installed correctly to obtain the correct timing. Before tightening the screws between the camshaft and camshaft pulley press hard (or hit with a plastic mallet) twice on the belt between the camshafts and then twice on the belt between the exhaust camshaft and the engine coolant pump. Do this to ensure that the gears mesh with the timing gear pulleys.
Secure drive belt
Press hard or knock the belt twice in the direction of arrow (1) and twice in the direction of arrow (2) using a rubber mallet.
Secure camshaft pulleys
Tighten the camshaft screws (2 x 3) to 20 Nm
Turn engine crankshaft two turns
Pull lock pin out of tensioner damping unit
Position upper timing cover.
Turn the crankshaft two revolutions and check that the markings on the crankshaft and camshaft pulleys are align.
Install
- the two fuel line clamps
- front timing cover
- accessory belt
- spark plug cover
- expansion tank
- vibration damper protective panel
- fender liner, wheel
Test function
Test run engine.