Replacement

Camshaft Timing Chain and Sprocket Replacement

Removal Procedure

Tools Required
^ J 28509-A Crankshaft Sprocket Remover
^ J 41371 Reluctor Wheel Remover

1. Disconnect the negative battery cable.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

For Vehicles equipped with OnStar (UE1) with Back Up Battery:

The Back Up Battery is a redundant power supply to allow limited OnStar functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar module). Do not disconnect the main vehicle battery or remove the OnStar fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the driver door should disable RAP) before disconnecting power. Disconnecting power to the OnStar module in any way while the ignition is On or with RAP activated may cause activation of the OnStar Back-Up Battery (BUB) system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The BUB is not rechargeable and once activated the BUB must be replaced.

2. Remove the air cleaner assembly.
3. Remove the engine cooling fan. Refer to Cooling System.
4. Remove the water pump. Refer to Cooling System.
5. Remove the engine front cover.

Important: If the crankshaft sensor reluctor ring is removed, a new crankshaft sensor reluctor ring must be installed.





6. Remove the reluctor ring from the crankcase using reluctor wheel remover.
7. Measure the camshaft timing chain free play. If the chain can be moved back and forth in, excess of 16 mm (0.625 inch), make a note that the camshaft timing chain and the sprockets must be replaced during assembly.





8. Align the timing marks.
9. Remove the camshaft sprocket bolts.





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





11. Remove the crankshaft sprocket using a crankshaft sprocket remover.
12. Remove the key, if necessary.

Installation

Tools Required
J 22102 Crankshaft Sprocket Installer

1. Install the crankshaft key, if necessary.

Important: Ensure that the sprocket alignment mark faces away from the engine block. Ensure that the sprocket is fully seated against the crank shoulder.





2. Install the crankshaft sprocket using the J 22102.

Important: Ensure that the following conditions exist:
^ The camshaft and the crankshaft timing marks are aligned
^ The camshaft dowel pin and the camshaft sprocket hole are properly aligned
^ The gears and the chain mesh





3. Install the camshaft timing chain to the camshaft sprocket.
4. Install the camshaft sprocket and the camshaft timing chain to the front of the camshaft.

Notice: Do not hammer the camshaft sprocket onto the camshaft. To do so may dislodge the rear camshaft plug and damage the camshaft.

5. Install the camshaft sprocket bolts. Use the bolts to draw the camshaft sprocket onto the camshaft.

Tighten
Tighten the camshaft sprocket bolts to 34 Nm (25 lb ft).

Important: Replace the crankshaft position sensor reluctor ring with a new component.





6. Install the crankshaft position sensor reluctor ring onto the crankshaft until the ring is completely seated against the crankshaft sprocket using the J 22102.
7. Install the engine front cover.
8. Install the water pump. Refer to Cooling System.
9. Install the engine cooling fan. Refer to Cooling System.
10. Install the air cleaner assembly.
11. Connect the negative battery cable.