For 1990-2009 cars

Important: Note the position and direction of the engine flywheel before removal. The flywheel does not use a locating pin for alignment and will not initially seat against the crankshaft flange, but will be pulled onto the crankshaft by the engine flywheel bolts. This procedure requires a three stage tightening process.

1. Install the manual transmission engine flywheel to the crankshaft, if applicable.
2. Install the automatic transmission engine flywheel to the crankshaft, if applicable.
3. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the threads of the flywheel bolts.

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.

4. Install the engine flywheel bolts.

Tighten

1. Tighten the engine flywheel bolts first pass in sequence to 20 N·m (15 lb ft).
2. Tighten the engine flywheel bolts second pass in sequence to 50 N·m (37 lb ft).
3. Tighten the engine flywheel bolts final pass in sequence to 100 N·m (74 lb ft).