Timing Belt: Service and Repair

TIMING BELT
REMOVAL

CAUTION: The 3.5L is NOT a freewheeling engine. Therefore, care should be taken not to rotate the camshafts or crankshaft with the timing belt removed.

1. Disconnect negative cable from battery.
2. Remove radiator fan module (Refer to 7 - COOLING/ENGINE/RADIATOR FAN - REMOVAL).
3. Remove accessory drive belts (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
4. Remove crankshaft damper and front timing belt covers (Refer to 9 - ENGINE/ENGINE BLOCK/VIBRATION DAMPER - REMOVAL) and (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN COVER(S) - REMOVAL).
5. Mark belt running direction, if timing belt is to be reused.

CAUTION: When aligning timing marks, always rotate engine by turning the crankshaft. Failure to do so will result in valve and/or piston damage.





6. Rotate engine clockwise until crankshaft mark aligns with the TDC mark on oil pump housing and the camshaft sprocket timing marks are between the marks on the rear covers (Fig. 143).

CAUTION: Align the camshaft sprockets between the marks on rear belt covers before timing belt removal or damage to valve and/or pistons could occur.

7. Using a ink or paint marker, mark the exact position of the camshaft sprocket timing mark relative to the two timing marks on the rear timing cover.

NOTE: When timing belt tensioner is removed from engine, always store in the vertical (plunger facing upward) position.





8. Remove the timing belt tensioner (Fig. 144) and remove timing belt.
9. When tensioner is removed from the engine it is necessary to compress the plunger into the tensioner body.

CAUTION: Compress the tensioner slowly, as damage to tensioner could result.





10. Place the tensioner into a vise and SLOWLY compress the plunger (Fig. 145). Total bleed down of tensioner should take about 5 minutes.

CAUTION: Index the tensioner in the vise the same way it is installed on the engine. This is to ensure proper pin orientation when tensioner is installed on the engine.

11. When plunger is compressed into the tensioner body install a pin through the body and plunger to retain plunger in place until tensioner is installed.

NOTE: When timing belt tensioner is removed from engine, always store in the vertical (plunger facing upward) position.


INSPECTION - TIMING BELT - IN VEHICLE
1. Remove the accessory drive belts (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
2. Remove front timing belt covers (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN COVER(S) - REMOVAL).





3. Inspect both sides of the timing belt. Replace belt if any of the following conditions exist (Fig. 146):
a. Hardening of back rubber back side is glossy without resilience and leaves no indent when pressed with fingernail.
b. Cracks on rubber back.
c. Cracks or peeling of canvas.
d. Cracks on rib root.
e. Cracks on belt sides.
f. Missing teeth.
g. Abnormal wear of belt sides. The sides are normal if they are sharp as if cut by a knife.
h. Vehicle mileage at component maintenance requirement. Refer to LUBRICATION AND MAINTENANCE.
4. If none of the above conditions are seen on the belt, the belt cover can be installed.

NOTE: If belt requires replacing, ensure the proper length belt is used.


INSTALLATION

CAUTION: This procedure can only be used when the camshaft sprockets HAVE NOT BEEN LOOSENED or removed from the camshafts (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN AND SPROCKETS - INSTALLATION).

CAUTION: If camshafts have moved from the timing marks, always rotate camshaft towards the direction nearest to the timing marks (DO NOT TURN CAMSHAFTS A FULL REVOLUTION OR DAMAGE to valves and/or pistons could result).





1. Align the crankshaft sprocket with the TDC mark on oil pump cover (Fig. 147).
2. Align the camshaft sprockets (to reference mark made upon removal) between the marks on the rear covers (Fig. 143).
3. Install the timing belt starting at the crankshaft sprocket going in a counterclockwise direction (Fig. 147). Install the belt around the last sprocket. Maintain tension on the belt as it is positioned around the tensioner pulley.
4. Holding the tensioner pulley against the belt, Install the tensioner into the housing and tighten to 28 Nm (250 in. lbs.). Each camshaft sprocket mark should still fall between the cover marks.
5. When tensioner is in place pull retaining pin to allow the tensioner to extend to the pulley bracket.
6. Rotate crankshaft sprocket two revolutions and check the timing marks on the camshafts and crankshaft. The marks should line up within their respective locations (Fig. 147). If marks do not line up, repeat procedure.
7. Install timing belt covers and crankshaft damper.
8. Install accessory drive belts.
9. Install radiator fan module.
10. Connect negative cable to battery.
11. Start engine and allow to idle for approximately one minute. Then, preferably using a DRBIII, operate the engine at speed of 1600-2000 RPM for ten minutes. This will help to bleed out any possible air in the timing belt tensioner.

NOTE: If air ingestion has occurred, the timing belt tensioner will be soft and may generate noise. This noise should disappear after no more than 15 minutes of engine running time.