For 1990-2009 cars only
- Install the heat shield (603) and bolts (604).
- Install the exhaust pipe studs (605).
- Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent, to the threads of the exhaust manifold bolts. Refer to Adhesives, Fluids, Lubricants, and Sealers .
- Install the exhaust manifold, NEW gasket, and bolts.
- Tighten the exhaust manifold bolts a first pass to 15 N·m (11 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
- Tighten the exhaust manifold bolts a final pass to 25 N·m (18 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
- Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
Notice: Refer to Fastener Notice in the Preface section.
Important:
• Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or on-board diagnostic (OBD) II system performance. • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material. • Do not apply sealant to the first 3 threads of the bolt.
Tighten
Tighten the bolts to 9 N·m (80 lb in).
Tighten
Tighten the studs to 20 N·m (15 lb ft).
Tighten
