For 1990-2009 cars only
- 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 NEW exhaust manifold bolts.
- Install the exhaust manifold and NEW exhaust manifold gasket.
- Install the NEW exhaust manifold 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 20 N·m (15 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.
- Install the exhaust manifold heat shield and bolts, if required.
- Install the air injection reaction (AIR) pipe, with check valve, NEW gasket, and bolts.
- Install the oxygen sensor into the intake manifold.
Important:
• Tighten the NEW 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 diagnostics (OBD) II system performance. • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.
Notice: Refer to Fastener Notice in the Preface section.
Tighten
Tighten
Tighten the heat shield bolts to 9 N·m (80 lb in).
Tighten
Tighten the AIR pipe to exhaust manifold bolts to 20 N·m (15 lb ft).
Tighten
Tighten the oxygen sensor to 42 N·m (30 lb ft).
