Installation Procedure

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to FASTENER NOTICE in Cautions and Notices.

Install the exhaust manifold heat shield and bolts, if required.
Tighten

Tighten the bolts to 9 N.m (80 lb in).

Fig 1: Installing Exhaust Manifold Heat Shield & Bolts - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.

Important: To assist in installing the exhaust manifold and gasket to the engine, tabs on a NEW exhaust manifold gasket will hold the gasket and bolts in place.
Install NEW exhaust manifold gaskets to the exhaust manifold.
Ensure that the exhaust manifold bolts/stud, and plug wire shields are held in place by the tabs on the exhaust manifold gaskets.

Fig 2: Installing Exhaust Manifold Gaskets - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.
Install the exhaust manifold and plug wire shields.
If reusing the old fasteners, apply threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts/stud.
Tighten the exhaust manifold bolts/stud.
Tighten

Tighten the bolts/stud to 30 N.m (22 lb ft).

Fig 3: Installing Exhaust Manifold & Plug Wire Shields - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.
Connect the ECT sensor electrical connector (5).

Fig 4: Connecting ECT Sensor Electrical Connector (4.3L)
Courtesy of GENERAL MOTORS CORP.
Install the spark plugs.
Tighten

Tighten the plugs to 15 N.m (11 lb ft).

Fig 5: Installing Spark Plugs - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.
Position the wire harness to the engine.
Install the spark plug wire retainer bolts.
Tighten

Tighten the bolts to 12 N.m (106 lb in).
Connect the spark plug wires to the spark plugs.
Raise the vehicle.

Fig 6: Installing Spark Plug Wires & Retainer Bolts - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.
Install the exhaust manifold pipe nuts.
Tighten

Tighten the nuts to 50 N.m (37 lb ft).
Lower the vehicle.

Fig 7: Installing Exhaust Manifold Pipe Nuts - Left (4.3L)
Courtesy of GENERAL MOTORS CORP.