Removal, Inspection and Installation of Balance Shaft Gears and Drive Belt

If noise increases due to the balance shaft drive belt, always adjust its tension first. This procedure can be performed without removing the timing cover. The tension of this belt is adjusted by the timing belt tensioner.

REMOVAL
PROCEDURE

1. Set the right cylinder piston to Top Dead Center (TDC) of the compression stroke (see Section Positioning No. 1 Piston at Top Dead Center (TDC)). Disconnect the negative battery cable.

If the vehicle is equipped with a stereo system with an anti-theft code, make sure you have the correct code to reactivate the audio system before disconnecting the battery!
2. Remove the power steering pump drive belt. Detach the pump from its support bracket (see Chapter Suspension and Steering) and move it aside.
3. Remove the alternator with its brackets from the timing belt cover (see Chapter Engine Electrical).
4. Raise the vehicle and support it on stands. Remove the engine undertray (see Chapter Body) and the left wheel arch cover.

5. Holding the crankshaft pulley from turning with a chain wrench, loosen its mounting bolt. Remove the pulley, using a puller if necessary.

6. Support the powertrain with a jack, placing a wooden block between the jack head and the oil pan to distribute the load. Remove the left powertrain mount together with its bracket (see Section Inspection and Replacement of Powertrain Mounts).
7. Remove the engine oil dipstick and its guide tube from the engine block.
8. Unscrew the bolts securing the timing cover to the engine block. Make a diagram showing the positions of the fasteners of different lengths, as they must be reinstalled in their original holes.

9. Remove the upper and lower timing belt covers.
10. Insert a bolt or a 6 x 100 mm rod into the special hole in the rear wall of the engine block (the hole is plugged with a bolt, which must be removed beforehand). This locks the rear balance shaft against rotation while the drive belt is removed.

Do not insert the bolt/rod deeper than 74 mm (mark the appropriate depth)!

For detailed information on balance shaft removal, refer to Balance Shafts Removal and Inspection (4-Cylinder Engines).

11. Temporarily install one of the timing belt cover bolts into the hole on the left side of the timing belt tensioner arm lever and tighten it to lock the tensioner while loosening the tensioner nut. Loosen the tensioner nut and push the tensioner roller away from the balance shaft drive belt to release its tension. Remove the belt.

If the belt is not being replaced, mark its original direction of rotation. This direction must be observed during installation.

12. If the balance shaft gears (front and rear) are damaged, remove their mounting bolts. The rear shaft is already locked by the bolt/rod inserted into the access hole at the rear of the engine block. The front shaft can be locked by inserting a suitable screwdriver into the service hole at its end (directly below the gear). Also remove the crankshaft gear.

The rear balance shaft gear set must be marked for position before removal to avoid errors during assembly.
INSPECTION
PROCEDURE

Carefully inspect the drive belt and balance shaft gears for signs of wear, cracks and other mechanical damage. Replace defective components.

INSTALLATION

PROCEDURE

1. Inspect the condition of the crankshaft front oil seal and replace it if necessary (refer to Crankshaft Front Oil Seal Replacement). Install the gear onto the front journal of the crankshaft, making sure the key on the journal aligns with the keyway in the gear hub.
2. Before installing the balance shaft drive belt and its gears, make sure the timing belt is installed correctly (refer to Timing Belt and Timing Gears Removal, Inspection and Installation). Also make sure the No. 1 piston remains at TDC at the end of its compression stroke (refer to Positioning No. 1 Piston at Top Dead Center (TDC)). Both balance shafts and the oil pump must be in their correct positions, with the rear shaft locked by the bolt/rod in the access hole. Move the drive belt tensioner away and lock it in the new position, following the procedure described in paragraph 11.

3. If removed, install the gears onto the balance shafts. Make sure both sets of alignment marks on the front balance shaft are aligned. Correct installation of the rear balance shaft is ensured automatically by the guide pin (or bolt) that enters the special service hole. Place the drive belt over the gears.

4. Check the alignment marks again, then install the gear mounting bolts and tighten them to the specified torque.

5. Now adjust the belt tension. Make sure the tensioner adjusting nut is loosened, then turn the crankshaft so that the camshaft gear rotates approximately three teeth. The slack in both belts must be fully taken up. Tighten the tensioner nut to the specified torque.

To check belt tension, press firmly on the belt with your thumb near the camshaft gear. The belt must be taut on both sides of the gear.
The timing belt and balance shaft drive belt tension can be adjusted without removing the timing covers. However, it is advisable to remove the covers so that the alignment of the timing marks can be checked.
6. If only the balance shaft drive belt was removed or replaced, remove the bolt used to lock the tensioner. Install the timing covers and tighten the mounting bolts to the specified torque. Make sure the edges of the gaskets do not protrude from under the ribs at the front cover joints.

7. When installing the crankshaft pulley, lubricate the thread and the underside of the bolt head. Install the bolt and tighten it to the specified torque.