Removal & Installation
3.5L & 4.0L Engines
- Before servicing the vehicle, refer to the Precautions section.
Use care when servicing a timing belt. Valve timing is absolutely critical to engine performance. If the valve timing marks on all drive sprockets are not properly aligned, engine damage will result. If only the belt and tensioner are being serviced, do not loosen the camshaft drive sprockets unless they are to be replaced. The sprockets have oversized openings and can be rotated several degrees in each direction on their shafts. This means the sprockets must be re-timed, requiring some special tools.
- Loosen the valve train rocker assemblies before servicing the timing components.
- Release the fuel system pressure using the recommended procedure.
- Remove the timing belt cover using the recommended procedure.
If the timing belt is to be reused, mark the timing belt with the running direction for installation.
WARNINGAlways align the timing marks always use the crankshaft to rotate the engine. Failure to do this will result in severe engine damage.
- Rotate the engine clockwise until the crankshaft mark aligns with the Top Dead Center (TDC) mark on the oil pump housing and the camshaft sprocket timing marks align with the marks on the rear cover.
- Remove the timing belt tensioner and the belt.
- Pre-load the timing belt tensioner as follows:
- Align the crankshaft sprocket with the TDC mark on the oil pump.
- Align the camshaft sprockets timing marks with the mark on the rear cover.
Install the belt starting at the crankshaft sprocket going in a counterclockwise direction. Install the belt around the last sprocket always maintaining tension on the belt as it is positioned around the tensioner pulley.
NOTEIf the camshaft gears have been removed it is only necessary to have the camshaft gear retaining bolts installed to a snug torque at this time.
- Holding the tensioner pulley against the belt, install the tensioner into the housing and tighten to 250 inch lbs. (28 Nm) making sure all the alignment marks remain aligned. Pull the pin from the tensioner and allow the tensioner to extend to the pulley bracket.
- Rotate the crankshaft sprocket 2 full turns and check the timing marks on the cam and crank shafts. Make sure the marks are aligned, if not repeat the procedure.
- if the camshafts were removed using a dial indicator, position the number 1 piston at TDC.
- Hold the camshaft sprocket hex with a 36mm wrench and tighten the right camshaft sprocket bolt to 75 ft. lbs. (102 Nm) plus an additional 90 degree turn. Tighten the left camshaft sprocket bolt to 85 ft. lbs. (115 Nm) plus an additional 90 degree turn.
- Remove the dial indicator. Install the spark plug and tighten to 20 ft. lbs. (28 Nm).
- Remove the camshaft alignment tools from the back of the cylinder heads and install the cam covers with new O-rings.
- Replace the timing belt cover using the recommended procedure.