Tools Required

Notice: In order to rotate the engine install a bolt with the same threads as the crankshaft, but do not use the crankshaft balancer bolt or a bolt longer than 1 inch, in the crankshaft. Failing to do so will cause damage to the bolt threads and the crankshaft threaded hole when removing the bolt.

1. Remove the crankshaft position (CKP) sensor reluctor ring. Refer to Crankshaft Position Sensor Reluctor Ring Replacement .
2. Install a 7/16-20 x 1 inch bolt into the end of the crankshaft.

Notice: Align the timing marks before removing the timing chain. If it is necessary to turn either the camshaft or the crankshaft with the timing chain removed, loosen or remove the valve rocker arms. Turning either the crankshaft or camshaft with the timing chain removed may cause the pistons to contact the valves, resulting in damage.

3. Rotate the crankshaft until:

3.1.	The timing marks on both sprockets line up.

3.2.	The number four cylinder is at top dead center (TDC) of the compression stroke.




4. Remove the camshaft sprocket bolts.



5. Remove the camshaft sprocket and the camshaft timing chain.



6. Using J 5825-A and an open end wrench, remove the crankshaft sprocket.



7. Remove the crankshaft balancer key.
8. Clean and inspect the timing chain and sprockets, if necessary. Refer to Camshaft Timing Chain and Sprocket Cleaning and Inspection in Engine Mechanical - 4.3L Unit Repair.

1. Install the key into the crankshaft keyway.

The crankshaft balancer key should be parallel to the crankshaft or with a slight incline.




2. Align the keyway of the crankshaft sprocket with the crankshaft balancer key.
3. Using J 5590 , install the crankshaft sprocket.




Important: Install the camshaft sprocket with the alignment mark at the 6 o'clock position.

4. Install the camshaft sprocket and the camshaft timing chain.



5. Ensure that the crankshaft sprocket is aligned at the 12 o'clock position and camshaft sprocket is aligned at the 6 o'clock position.




Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Important:  Do not use a hammer to install the camshaft sprocket onto the camshaft. To do so may dislodge the expansion cup plug.

6. Install camshaft sprocket bolts.

Tighten
Tighten the camshaft sprocket bolts to 25 N·m (18 lb ft).

7. Remove the bolt that was installed in the end of the crankshaft.
8. Install the CKP sensor reluctor ring. Refer to Crankshaft Position Sensor Reluctor Ring Replacement .