Exhaust Noise
| Condition | Action |
|---|---|
| CAUTION: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system. DEFINITION: An audible or physical noise due to a faulty component or damaged components causing a loose or misaligned exhaust system resulting in a rattle or vibration noise (buzz, groan, hum).Refer to Symptoms - Engine Exhaust prior to beginning this table. | |
| Popping or hissing noise | Exhaust leak Refer to Exhaust Leakage |
| Loud exhaust | Compare to a known good vehicle. Inspect for a damaged or failed muffler or resonator. Replace the faulty muffler or resonator. Refer to Muffler Replacement . |
| External rattle or vibration noise | Inspect for a bent or loose hanger, loose heat shield, or loose clamp. Inspect for a exhaust pipe causing interference. Repair or replace the affected component. Refer to the affected component's service procedure. |
| Internal rattle | Test the components by tapping with a rubber mallet to confirm a rattle. Replace the faulty catalytic converter, resonator, or muffler. Refer to one of the following procedures: Catalytic Converter Replacement (4.2L Engine) Catalytic Converter Replacement (5.3L Engine) Muffler Replacement |
| CAUTION |
|---|
| While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system. |
Exhaust Noise
Scheme 19
Scheme 20
- Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-268088-S13434065972007101800000) .
- Loosen and remove the exhaust pipe bolts from the exhaust manifold.
- Lower the vehicle.
- Remove the manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement»(ref-268155-S07229583832007101800000) .
- Loosen and remove the exhaust manifold bolts.
- Remove the exhaust manifold.
- Remove the exhaust manifold gasket.
Scheme 21
Scheme 22
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Scheme 24
- Install a new exhaust manifold gasket.
- Install the exhaust manifold. NOTE: Refer to «Fastener Notice»(ref-268087-S07010920292007101800000) .
- With threadlock GM P/N 12345493 (Canadian P/N 10953488) on the manifold bolts, install the bolts onto the manifold. Tighten: Tighten the exhaust manifold bolts first pass in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts second pass in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts final pass in sequence to 20 N.m (15 lb ft).
- Install the exhaust manifold heat shield studs, if required. Tighten: Tighten the heat shield studs to 10 N.m (89 lb in).
- Install the manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement»(ref-268155-S07229583832007101800000) .
- Raise the vehicle.
- Install the exhaust pipe to the manifold with seal and secure the pipe with the nuts. Tighten: Tighten the exhaust pipe nuts to 50 N.m (37 lb ft).
- Lower the vehicle.
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- Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-268088-S13434065972007101800000) .
- Remove the nuts securing the catalytic converter to the left exhaust manifold.
- Lower the vehicle.
- Remove the spark plugs. Refer to «Spark Plug Replacement»(ref-268122-S04202183032007101800000) .
- Remove the heat shield bolts, and shield from the exhaust manifold.
- Remove the exhaust manifold bolts, manifold, and gasket.
- Discard the gasket.
- Clean and inspect the exhaust manifold. Refer to «Exhaust Manifold Cleaning and Inspection»(ref-268156-S40807375832007101800000) .