Intermittent
Test the vehicle under the same conditions that the customer reported in order to verify the system is operating as designed.
Exhaust Leakage
| Problem | Action |
|---|---|
| CAUTION: While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system. DEFINITION: An exhaust leak may show stains at the area of the leak. The leak may be felt by holding a hand close to the suspected areas or using a smoke pencil. The leak may make a popping or hissing noise.Refer to Symptoms - Engine Exhaust prior to beginning this table. | |
| Misaligned or improperly installed exhaust system components. | Align and tighten the components to the specifications. Refer to Fastener Tightening Specifications . Ensure the exhaust hangers are in the proper locations and not loose. Refer to Exhaust System Insulator, Hanger, Bracket Replacement (6.6L Engine with RPO YF2) . |
| Exhaust leaks at the following connections: Exhaust manifold to pipe Flanges Pipe clamps | Tighten the components to the specifications. Refer to Fastener Tightening Specifications . |
| Seals or gaskets leaking. Exhaust manifold to cylinder head Exhaust pipes to exhaust manifold Catalytic converter connection EGR connections AIR connections to the exhaust manifold or cylinder head | Replace the leaking seal or gasket. Refer to the affected components procedure for service. |
| Irregularities at the mating surfaces on the flange connections. | Repair as required or replace the affected component. Refer to the affected components procedure for service. |
| Exhaust manifold cracked or broken. | Replace the exhaust manifold Refer to Exhaust Manifold Replacement - Left Side (4.3L Engine) or Exhaust Manifold Replacement - Left Side (4.8L, 5.3L, and 6.0L Engine) or Exhaust Manifold Replacement - Left Side (6.6L Engine) or Exhaust Manifold Replacement - Left Side (8.1L Engine) or Exhaust Manifold Replacement - Right Side (4.3L Engine) or Exhaust Manifold Replacement - Right Side (4.8L, 5.3L, and 6.0L Engines) or Exhaust Manifold Replacement - Right Side (6.6L Engine) or Exhaust Manifold Replacement - Right Side (8.1L Engine) . |
| Exhaust system component connection welds leaking. | Replace the leaking component. Refer to the affected component's procedure for service. |
| Muffler or resonator (if equipped) damaged or leaking at the seams. | Replace the affected muffler or resonator. Refer to one of the following procedures: Muffler Replacement (4.3L, 4.8L, and 5.3L Engines) or Muffler Replacement (6.0L, 6.6L, and 8.1L Engines) Resonator replacement |
| CAUTION |
|---|
| While engine is operating, the exhaust system will become extremely hot. To prevent burns avoid contacting a hot exhaust system. |
Exhaust Leakage
Resonator
Some exhaust systems are equipped with a resonator. The resonator, located either before or after the muffler, allows the use of mufflers with less back pressure. Resonators are used when vehicle characteristics require specific exhaust tuning.
Catalytic Converter
The catalytic converter is an emission control device added to the engine exhaust system in order to reduce hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) pollutants from the exhaust gas.
The catalytic converter is comprised of a ceramic monolith substrate, supported in insulation and housed within a sheet metal shell. The substrate may be washcoated with 3 noble metals
- Platium (Pt)
- Palladium (Pd)
- Rhodium (Rh)
The catalyst in the converter is not serviceable.
Muffler
The exhaust muffler reduces the noise levels of the engine exhaust by the use of tuning tubes. The tuning tubes create channels inside the exhaust muffler that lower the sound levels created by the combustion of the engine.