Timing Chain and Sprocket
Camshaft Timing Chain and Sprocket Replacement
Removal Procedure
Tool Required
- J 22888-20A Crankshaft Sprocket Puller
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 crankcase front cover.
3. Align the crankshaft sprocket and camshaft sprocket timing marks with the alignment tabs on the timing chain tensioner.
4. Remove the timing chain tensioner bolts.
5. Remove the camshaft sprocket bolt.
6. Remove the camshaft sprocket and timing chain.
7. Remove the Torx bolt and the tensioner assembly.
8. Remove the crankshaft sprocket using J 22888-20A.
Installation Procedure
Tool Required
- J 5590 Crankshaft Sprocket Installer.
1. Install the crankshaft sprocket using J 5590. Make sure that the crankshaft sprocket is seated against the crankshaft.
2. Install the timing chain and install the timing chain tensioner.
3. Compress the timing chain tensioner spring.
4. Insert a cotter pin or a nail into the hole in the tensioner to retain the timing chain tensioner shoe.
5. Install the timing chain tensioner. Do not tighten the timing chain tensioner bolts.
6. Align the crankshaft timing marks with the tab on the timing chain tensioner.
7. Align the camshaft timing mark with the tab on the timing chain tensioner.
8. Install the camshaft sprocket and install the timing chain. Tighten the timing chain tensioner bolts to 24 Nm (18 lb ft). Tighten the camshaft sprocket bolt to 130 Nm (96 lb ft).
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.
9. Remove the cotter pin or nail from the hole in the timing chain tensioner.
10. Install the crankcase front cover.
11. Connect the negative battery cable.