Checking and Adjusting Tension
CHECKING AND ADJUSTING BALANCE SHAFT TOOTHED BELT TENSIONNOTE: The toothed belt tension must be checked and adjusted only when the engine is cold (room temperature).
1. Undo and remove air cleaner assembly and engine underside protection.
2. Remove Poly-Rib belt or power pump belt, respectively.
NOTE: Before undoing the lock nuts, always start by slightly loosening the hexagon head bolts of the link rod.
3. Remove toothed belt cover. Undo idler until the idler no longer places a preload on the toothed belt.
TDC Mark On Cam:
4. Rotate crankshaft clockwise until TDC mark on camshaft drive sprocket lines up with mark on toothed belt cover.
TDC Mark (Double Mass Flywheel):
5. The TDC mark on the flywheel (double- mass flywheel) must also line up.
6. Check basic position of balance shaft drive sprockets. The marks on the sprockets must line up with the marks on the rear toothed belt cover.
7. Prepare Special Tool 9201 for check. Pull out lock pin of Special Tool and push measuring pin opposite the lock pin all the way out. Align non-return pointer to measuring pointer.
8. Push Special Tool onto toothed belt. Push measuring button (arrows) slowly in until engagement of the lock pin is felt and read off displayed value on dial gauge.
NOTE: To avoid reading errors, the non-return pointer must always be aligned to the measuring pointer after the lock pin has engaged (turn counterclockwise).
Adjusting value: (new and used belts) 2.7 ± 0.3 dial values If required, correct toothed belt tension.
ADJUSTING
9. The sliding blocks must rest on the belt along their entire surface. During the measuring process, the Special Tool must neither be twisted nor moved on the belt.
10. When tensioning, rotate tensioning pulley clockwise. When slackening, rotate tensioning pulley counterclockwise. Tighten hexagon nut to 45 Nm (33 ft lb), using a second wrench to lock.
1 - Idler pulley
2 - Balance shaft
3 - Tensioning pulley
11. After the toothed belt has been adjusted, follow by adjusting the idler. Using Special Tool 9207 or a feeler gauge (0.5 mm) (0,020 in), set idler pulley to a clearance of 0.5 mm (0.020 in) to the toothed belt in bottom balance shaft area and preload upper toothed belt train by 0 to 1 mm (0 - 0.040 in)at same time. Tighten idler pulley in this position. If the adjustment travel is not sufficient, turn idler pulley by 180 and repeat adjustment. Tighten hexagon head nut to 45 Nm (33 ft lbs), using a second wrench to lock.
12. Fit toothed belt cover. Install Poly-Bib belt or power pump belt, respectively, and ad- just according to specification. Fit belt or power pump belt, respectively, and adjust according to specification. Fit engine undertray and air assembly.