Engine Exhaust System Chevrolet Impala VIII

SPECIFICATIONS

Fastener Tightening Specifications

Diagnostic Starting Point - Engine Exhaust

Begin the system diagnosis by reviewing the system Description and Operation. Reviewing the information will help you determine the correct symptom diagnostic procedure when a malfunction exists. It will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Exhaust in order to identify the correct procedure for diagnosing the system.

Symptoms - Engine Exhaust

1. Review the Exhaust System Description and Operation in order to familiarize yourself with the system functions. Refer to «Exhaust System Description»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system__exhaust-system-description) .
2. All diagnostics on a vehicle should follow a logical process. Strategy Based Diagnostics is a uniform approach for repairing all systems. The diagnostic flow is the place to start when repairs are necessary and may always be used in order to resolve a system problem.

Visual/Physical Inspection

1. Inspect for aftermarket or non-OEM devices such as, but not including; tailpipe extensions, headers, and exhaust cutouts. This could affect the operation and proper performance of the exhaust system.
2. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, engine temperature, engine load, and frequency of concern.
3. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause any symptom.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating as designed.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. Loss of Power. Refer to «Restricted Exhaust»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
2. Poor acceleration. Refer to «Restricted Exhaust»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
3. Poor fuel economy. Refer to «Restricted Exhaust»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Excessive smoke - diesel. Refer to «Restricted Exhaust»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
5. Exhaust hissing noise. Refer to «Exhaust Leakage»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
6. Exhaust popping noise. Refer to «Exhaust Leakage»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
7. Exhaust rattle noise. Refer to «Exhaust Leakage»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
8. Loud exhaust noise. Refer to «Exhaust Noise»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
9. Exhaust buzz, groan, hum noise. Refer to «Exhaust Noise»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .

Diagnostic Aids

For dual exhaust systems a quick check of exhaust flow will help determine which side of the exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect, and the diagnosis should begin there.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 4) - The exhaust system has very low back pressure under normal conditions. If the exhaust system is restricted, a significant increase in the exhaust pressure is noticed on the J 35314-A Exhaust Back Pressure Gage. Removing the HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
2. 5) - This step will isolate the catalytic converter from the remainder of the exhaust system.
3. 8) - Confirming that the condition has been fixed is essential. If the symptom still exists and the vehicle has a dual exhaust system, proceed to Step 2 and repeat the diagnostic procedure on the opposite exhaust pipe.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

1. Disconnect the negative battery cable.
2. Remove the air cleaner intake duct.
3. Remove the right engine mount strut bracket. Refer to «ENGINE MOUNT STRUT (RIGHT) -- REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-34l-v6-vin-e-on-vehicle) .
4. Remove the exhaust crossover pipe heat shield bolts and the heat shield.
5. Remove the exhaust crossover pipe nuts from the left exhaust manifold.
6. Remove the left exhaust manifold heat shield bolts.
7. Remove the left exhaust manifold heat shield.
8. Remove the left exhaust manifold nuts.
9. Remove the left exhaust manifold.
10. Remove the left exhaust manifold gasket.
11. Clean and inspect the left exhaust manifold mating surfaces.

Installation Procedure

1. Install the left exhaust manifold gasket.
2. Install the left exhaust manifold.
3. Install the left exhaust manifold nuts. Tighten the left exhaust manifold nuts to 16 N.m (12 ft lbs).
4. Install the left exhaust manifold heat shield.
5. Install the left exhaust manifold heat shield bolts. Tighten the left exhaust manifold heat shield bolts to 10 N.m (89 in lbs).
6. Install the exhaust crossover pipe nuts to the left exhaust manifold. Tighten the exhaust crossover pipe nuts to 25 N.m (18 ft lbs).
7. Install the exhaust crossover pipe heat shield and bolts. Tighten the exhaust crossover pipe heat shield bolts to 10 N.m (89 in lbs).
8. Install the right engine mount strut bracket.
9. Install the air cleaner intake duct.
10. Connect the negative battery cable.

Scheme 6

1. Remove the fuel injector sight shield. Refer to «FUEL INJECTOR SIGHT SHIELD - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .
2. Remove the right and left engine mount struts. Refer to «ENGINE MOUNT STRUT (RIGHT) -- REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-34l-v6-vin-e-on-vehicle) and «ENGINE MOUNT STRUT (LEFT) - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .
3. Remove the exhaust crossover pipe from the left exhaust manifold. Refer to «Exhaust Crossover Pipe Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Remove the spark plug wires from the left side spark plugs.
5. Remove the oil level indicator tube.
6. Remove the left engine lift bracket nut, bolt and engine lift bracket.
7. Remove the left exhaust manifold heat shield nuts and the exhaust manifold heat shield.
8. Remove the left exhaust manifold bolts and studs.
9. Remove the left exhaust manifold and gasket.
10. Clean and inspect the left exhaust manifold mating surfaces.

1. Install the left exhaust manifold gasket and the left exhaust manifold to the cylinder head.
2. Install the left exhaust manifold bolts and studs to the left exhaust manifold. Tighten the exhaust manifold bolts and studs to 30 N.m (22 ft lbs).
3. Install the left exhaust manifold heat shield to the exhaust manifold.
4. Install the exhaust manifold heat shield nuts. Tighten the exhaust manifold heat shield nuts to 20 N.m (15 ft lbs).
5. Install the left engine lift bracket, nut and bolt to the engine. Tighten the engine lift bracket nut and bolt to 30 N.m (22 ft lbs).
6. Install the oil level indicator tube.
7. Install the spark plug wires to the left side spark plugs.
8. Install the exhaust crossover to the left exhaust manifold. Refer to «Exhaust Crossover Pipe Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
9. Install the right and left engine mount struts. Refer to «ENGINE MOUNT STRUT (RIGHT) -- REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-34l-v6-vin-e-on-vehicle) and «ENGINE MOUNT STRUT (LEFT) - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .
10. Install the fuel injector sight shield.

Scheme 7

Scheme 8

1. Remove the windshield wiper motor cover.
2. Remove the air cleaner intake duct.
3. Remove the accelerator cable bracket from the throttle body.
4. Rotate the engine for service access. Refer to «ROTATING THE ENGINE FOR SERVICE ACCESS»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-34l-v6-vin-e-on-vehicle__rotating-the-engine-for-service-access) .
5. Remove the manifold air pressure (MAP) sensor.
6. Remove the exhaust gas recirculation (EGR) pipe.
7. Remove the ignition module and the ignition coils with the bracket.
8. Remove the spark plug wires from the right side spark plugs.
9. Disconnect the heated oxygen (HO2S) sensor electrical connector.
10. Remove the evaporative emissions (EVAP) solenoid bracket.
11. Remove the exhaust crossover heat shield bolts.
12. Remove the exhaust crossover heat shield.
13. Remove the exhaust crossover pipe nuts from the right exhaust manifold. Refer to «Exhaust Crossover Pipe Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
14. Raise and support the vehicle.
15. Remove the catalytic converter. Refer to «Catalytic Converter Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
16. Remove the exhaust manifold heat shield bolts.
17. Remove the exhaust manifold heat shields.
18. Remove the exhaust manifold nuts.
19. Remove the exhaust manifold.
20. Remove the exhaust manifold gasket.
21. Clean and inspect the right exhaust manifold mating surfaces.
22. If replacing the right exhaust manifold, remove the heated oxygen (HO2S) sensor.

1. If removed, install the heated oxygen (HO2S) sensor.
2. Install the exhaust manifold gasket.
3. Install the exhaust manifold.
4. Install the exhaust manifold nuts. Tighten the exhaust manifold nuts to 16 N.m (12 ft lbs).
5. Install the exhaust manifold lower heat shield.
6. Install the exhaust manifold upper heat shield.
7. Install the exhaust manifold heat shield bolts. Tighten the exhaust manifold heat shield bolts to 10 N.m (89 in lbs).
8. Install the catalytic converter.
9. Lower the vehicle.
10. Install the exhaust crossover pipe nuts to the right exhaust manifold.
11. Install the exhaust crossover pipe heat shield.
12. Install the exhaust crossover pipe heat shield bolts. Tighten the exhaust crossover pipe heat shield bolts to 10 N.m (89 in lbs).
13. Install the evaporative emissions (EVAP) solenoid bracket.
14. Connect the heated oxygen (HO2S) sensor electrical connector.
15. Install the spark plug wires to the right side spark plugs.
16. Install the ignition module and the ignition coils with the bracket.
17. Install the exhaust gas recirculation (EGR) valve to the intake manifold.
18. Install the manifold absolute pressure (MAP) sensor.
19. Rotate the engine back to the original position.
20. Install the accelerator cable bracket to the throttle body.
21. Install the throttle body air inlet duct.
22. Install the windshield wiper motor cover.

Scheme 9

Scheme 10

Scheme 11

1. Remove the fuel injector sight shield. Refer to «FUEL INJECTOR SIGHT SHIELD - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .
2. Remove the cross vehicle brace.
3. Remove the exhaust crossover pipe from the right exhaust manifold. Refer to «Exhaust Crossover Pipe Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Remove the AIR pipe, if equipped.
5. Raise and support the vehicle.
6. Remove the exhaust manifold pipe stud nuts and the catalytic converter pipe from the right exhaust manifold.
7. Remove the exhaust gas recirculation (EGR) adapter pipe from the right exhaust manifold.
8. Lower the vehicle.
9. Rotate the engine to access the right side of the engine. Refer to «ROTATING THE ENGINE FOR SERVICE ACCESS»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-34l-v6-vin-e-on-vehicle__rotating-the-engine-for-service-access) .
10. Disconnect the heated oxygen (HO2S) sensor wiring harness connector (3) and remove the heated oxygen (HO2S) sensor connector (4) from the fuel injector sight shield bracket (1).
11. Remove the spark plug wires from the right side spark plugs.
12. Remove the right engine lift bracket bolt and nut.
13. Remove the right engine lift bracket.
14. Remove the fuel injector sight shield bracket nuts.
15. Remove the fuel injector sight shield bracket.
16. Remove the transaxle fluid filler tube.
17. Remove the right exhaust manifold bolts and nuts.
18. Remove the right exhaust manifold.
19. Remove the right exhaust manifold gasket.
20. Remove the upper right exhaust manifold heat shield.
21. Remove the lower right exhaust manifold heat shield.
22. If replacing the right exhaust manifold, remove the heated oxygen sensor from the right exhaust manifold.
23. Clean and inspect the right exhaust manifold mating surfaces.

1. If replacing the right exhaust manifold, install the heated oxygen sensor to the right exhaust manifold.
2. Install the lower right exhaust manifold heat shield.
3. Install the upper right exhaust manifold heat shield. Important: Whenever the EGR pipe is removed from the right exhaust manifold, the outlet pipe should be inspected for leaks during installation. If leaks are present, replace the EGR adapter.
4. Install the new right exhaust manifold gasket.
5. Install the right exhaust manifold.
6. Install the exhaust manifold bolts and nuts. Tighten the exhaust manifold bolts and nuts to 30 N.m (22 ft lbs).
7. Install the transaxle fluid filler tube.
8. Install the fuel injector sight shield bracket.
9. Install the fuel injector sight shield bracket nuts. Tighten the fuel injector sight shield bracket nuts to 30 N.m (22 ft lbs).
10. Install the right engine lift bracket.
11. Install the right engine lift bracket bolt and nut. Tighten the right engine lift bracket bolt and nut to 30 N.m (22 ft lbs).
12. Install the right spark plug wires.
13. Install the heated oxygen (HO2S) sensor electrical connector (4) to the fuel injector sight shield bracket (1) and connect the heated oxygen (HO2S) sensor wiring harness electrical connector (3).
14. Rotate the engine back to the original position.
15. Raise the vehicle.
16. Install the EGR adapter pipe and bolt to the right exhaust manifold. Tighten the EGR adapter pipe bolt to 29 N.m (21 ft lbs).
17. Install the catalytic converter pipe to the right exhaust manifold.
18. Install the exhaust manifold pipe stud nuts to the exhaust manifold studs. Tighten the exhaust manifold pipe stud nuts to 32 N.m (24 ft lbs).
19. Lower the vehicle.
20. Install the AIR pipe, if equipped.
21. Install the exhaust crossover pipe to the right exhaust manifold. Refer to «Exhaust Crossover Pipe Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Exhaust Crossover Pipe Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
22. Install the cross vehicle brace.
23. Install the fuel injector sight shield. Refer to «FUEL INJECTOR SIGHT SHIELD - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .

Scheme 12

Scheme 13

1. Remove the air cleaner intake duct.
2. If equipped remove the AIR pipe.
3. Remove the thermostat by-pass pipe.
4. Remove the exhaust crossover heat shield bolts.
5. Remove the exhaust crossover heat shield.
6. Remove the exhaust crossover pipe nuts.
7. Remove the exhaust crossover pipe.

1. Install the exhaust crossover pipe.
2. Install the exhaust crossover pipe nuts. Tighten the nuts to 25 N.m (18 ft lbs).
3. Install the exhaust crossover heat shield.
4. Install the exhaust crossover heat shield bolts. Tighten the bolts to 10 N.m (89 in lbs).
5. Install the thermostat by-pass pipe.
6. If equipped install the AIR pipe.
7. Install the air cleaner intake duct.

Scheme 14

1. Remove the fuel injector sight shield. Refer to «FUEL INJECTOR SIGHT SHIELD - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle)
2. Remove the air cleaner intake duct.
3. Remove the exhaust crossover heat shield nuts.
4. Remove the exhaust crossover heat shield.
5. Remove the exhaust crossover pipe bolts.
6. Remove the exhaust crossover pipe.
7. Remove the exhaust crossover pipe seal.

1. Install the exhaust crossover pipe seal to the exhaust crossover pipe at the right exhaust manifold connection.
2. Install the exhaust crossover pipe.
3. Install the exhaust crossover pipe bolts. Tighten the bolts to 20 N.m (15 ft lbs).
4. Install the exhaust crossover heat shield.
5. Install the exhaust crossover heat shield nuts. Tighten the nuts to 20 N.m (15 ft lbs).
6. Install the air cleaner intake duct.
7. Install the fuel injector sight shield. Refer to «FUEL INJECTOR SIGHT SHIELD - REPLACEMENT»(/chevrolet/impala/viii-1999-2006/remont/mechanical/#engine-mechanical-38l-on-vehicle) .

Scheme 15

1. Raise and support the vehicle. Important: Use caution handling the pipe that contains an oxygen sensor. Do not cut the wire. For removal or repositioning disconnect the HO2S electrical connector.
2. Remove the exhaust manifold pipe stud nuts from the exhaust manifold studs. Important: Support the exhaust system where hangers are removed.
3. Remove the catalytic converter exhaust hangers.
4. Reposition the exhaust system.
5. Remove the exhaust manifold pipe gasket.

1. Install the exhaust manifold pipe gasket.
2. Install the exhaust system to the original position.
3. Install the catalytic converter exhaust hangers.
4. Remove the support from the exhaust system.
5. Install the exhaust manifold pipe nuts to the exhaust manifold pipe studs. Tighten the nuts to 35 N.m (26 ft lbs).
6. Inspect the exhaust system for leaks and underbody contact.
7. Lower the vehicle.

Removal Procedure

1. Raise and support the vehicle. Important: Use caution handling the pipe that contains an oxygen sensor. Do not cut the wire. For removal or repositioning disconnect the HO2S electrical connector.
2. Remove the exhaust manifold nuts from the exhaust manifold pipe studs. Important: Support the exhaust system where hangers are removed.
3. Remove the catalytic converter exhaust hangers.
4. Reposition the exhaust system.
5. Remove the exhaust manifold pipe gasket.

1. Install the exhaust manifold pipe gasket.
2. Install the exhaust system to the original position.
3. Install the catalytic converter exhaust hangers.
4. Remove the support from the exhaust system.
5. Install the exhaust manifold pipe nuts to the exhaust manifold pipe studs. Tighten the nuts to 35 N.m (26 ft lbs).
6. Inspect the exhaust system for leaks and underbody contact.
7. Lower the vehicle.

Important; Replace the entire converter assembly in order to properly service the 3-way catalytic converter.

Scheme 16

1. Raise and support the vehicle.
2. Remove the exhaust manifold pipe nuts from the exhaust manifold pipe studs.
3. Remove the catalytic converter nuts from the exhaust pipe.
4. Remove the 3-way catalytic converter.
5. Clean the 3-way catalytic converter mating surfaces.

Note. To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.

1. Install a new catalytic converter gasket.
2. Install a new exhaust manifold pipe gasket.
3. Position and support the new 3-way catalytic converter under the vehicle.
4. Install the exhaust pipe to the 3-way catalytic converter with the catalytic converter nuts. Do not tighten the nuts.
5. Install the exhaust manifold pipe nuts to the exhaust manifold pipe studs. Tighten the exhaust manifold pipe nuts to the exhaust manifold pipe stud to 32 N.m (24 ft lbs). Tighten the catalytic converter nuts to the 34 N.m (25 ft lbs).
6. Lower the vehicle.
7. Inspect the exhaust system for leaks.

Important: The 3-way catalytic converter is serviced by replacing the entire assembly. Always replace the gasket at the front flange when servicing the 3-way catalytic converter assembly. Never install the original gasket.

Scheme 17

Scheme 18

1. Raise and support the vehicle.
2. Disconnect the heated oxygen sensor (HO2S) electrical connector.
3. Remove the exhaust manifold pipe stud nuts.
4. Remove the catalytic converter bolts.
5. Remove the 3-way catalytic converter.
6. Remove the exhaust manifold pipe gasket at the catalytic converter front flange.
7. Remove the heated oxygen sensor (HO2S).

1. Install the heated oxygen sensor (HO2S).
2. Install a new exhaust manifold pipe gasket to the exhaust manifold pipe studs.
3. Install and support the three way catalytic converter.
4. Install the catalytic converter bolts.
5. Install the exhaust manifold pipe stud nuts. Tighten the exhaust manifold pipe stud nuts to 32 N.m (24 ft lbs). Tighten the catalytic converter bolts to 45 N.m (33 ft lbs).
6. Connect the heated oxygen sensor (HO2S) electrical connector.
7. Lower the vehicle.
8. Inspect the exhaust system for leaks.

Scheme 19

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the exhaust pipe rear hanger insulator from the exhaust pipe rear hanger bracket.
4. Remove the exhaust pipe rear hanger bolt.
5. Remove the exhaust pipe rear hanger bracket.
6. Remove the exhaust pipe rear hanger insulators from the exhaust muffler rear hanger bracket.
7. Remove the rear bumper impact bar bolt.
8. Remove the exhaust muffler rear hanger bracket.

1. Install the exhaust muffler rear hanger bracket.
2. Install the rear bumper impact bar bolt. Tighten the rear bumper impact bar bolts to 25 N.m (18 ft lbs).
3. Install the exhaust pipe rear hanger insulators to the exhaust muffler rear hanger bracket.
4. Install the exhaust pipe rear hanger bracket.
5. Install the exhaust pipe rear hanger bracket bolt. Tighten the exhaust pipe rear hanger bracket bolt to 25 N.m (18 ft lbs).
6. Install the exhaust pipe rear hanger insulator to the exhaust pipe rear hanger bracket.
7. Remove the support from the exhaust system.
8. Inspect the exhaust system for underbody contact.
9. Lower the vehicle.

Scheme 20

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the exhaust pipe hanger insulator from the exhaust pipe hanger bracket.
4. Remove the exhaust pipe hanger bolt.
5. Remove the exhaust pipe hanger bracket.
6. Remove the exhaust pipe rear hanger insulators from the muffler rear hanger brackets.
7. Remove the rear bumper impact bar bolts.
8. Remove the exhaust muffler rear hanger brackets.

1. Install the exhaust muffler rear hanger brackets.
2. Install the rear bumper impact bar bolts. Tighten the bolts to 25 N.m (18.4 ft lbs).
3. Install the exhaust pipe rear hanger insulators to the muffler and the rear hanger bracket.
4. Install the exhaust pipe hanger bracket.
5. Install the exhaust pipe hanger bolt. Tighten the bolt to 25 N.m (18.4 ft lbs).
6. Install the exhaust pipe rear hanger insulator to the exhaust pipe hanger bracket.
7. Remove the support from the exhaust system.
8. Inspect the exhaust system for underbody contact.
9. Lower the vehicle.

Important: The muffler is serviced as a complete assembly and cannot be serviced separately.

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the catalytic converter from the muffler. Refer to «Catalytic Converter Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Remove the muffler from the exhaust hangers.
5. Clean the catalytic converter and the muffler gasket mating surfaces.

1. Install the muffler to the exhaust hangers.
2. Support the exhaust system.
3. Install a new gasket to the catalytic converter and the muffler.
4. Install the catalytic converter to the muffler.
5. Remove the exhaust system support.
6. Lower the vehicle.
7. Inspect for exhaust leaks.

Important: The muffler is serviced as a complete assembly and cannot be serviced separately.

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the catalytic converter from the muffler. Refer to «Catalytic Converter Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Remove the exhaust system from the exhaust hangers.
5. Clean the catalytic converter and the muffler gasket mating surfaces.

1. Install the muffler to the exhaust hangers.
2. Support the exhaust system.
3. Install a new gasket to the catalytic converter and the muffler.
4. Install the catalytic converter to the muffler.
5. Remove the exhaust system support.
6. Lower the vehicle.
7. Inspect for exhaust leaks.

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the 3-way catalytic converter pipe hangers.
4. Inspect the 3-way catalytic converter brackets for serviceability. Repair or replace as necessary.

1. Install the 3-way catalytic converter pipe hangers.
2. Remove the support from the exhaust system and the vehicle.
3. Inspect the exhaust system for underbody contact.
4. Lower the vehicle.

Scheme 21

Scheme 22

1. Raise and support the vehicle.
2. Support the exhaust system.
3. Remove the catalytic converter. Refer to «Catalytic Converter Replacement (3.4L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) or «Catalytic Converter Replacement (3.8L)»(/chevrolet/impala/viii-1999-2006/remont/exhaust/#engine-exhaust-system) .
4. Remove the heated oxygen sensor (HO2S) wiring harness (3) from the catalytic converter heat shield (4).
5. Remove the catalytic converter heat shield rivets.
6. Remove the catalytic converter heat shield.

1. Install the catalytic converter heat shield.
2. Install the converter heat shield rivets.
3. Install the heated oxygen sensor (HO2S) wiring harness (3) to the catalytic converter heat shield (4).
4. Install the catalytic converter.
5. Remove the support from the exhaust system.
6. Lower the vehicle.
7. Inspect the exhaust system for leaks.

Exhaust System Description

Important: Use of non-OEM parts may cause driveability concerns.

The exhaust system carries exhaust gases, treated by the catalytic converter, through a resonator, if applicable and into the exhaust muffler where exhaust noise is lessened.

In order to secure the exhaust pipe to the exhaust manifold, a flange and seal-joint coupling is utilized. The exhaust system may utilize a slip-joint coupling design with a clamp and a U-bolt or a flange connection with a gasket.

Exhaust hangers and rubber insulators help to support the weight of the exhaust pipe along with insulating any exhaust system vibration, rattle, or noise.

Exhaust hangers also space the exhaust system away from the underbody of the vehicle and allows the exhaust system to expand as the exhaust system warms up.

Exhaust heat shields are used to protect the body and other components from damage due to the heat from the exhaust system.

The exhaust system may be comprised of the following components

1. Exhaust manifold
2. Exhaust pipes
3. Catalytic converters
4. Exhaust muffler
5. Exhaust resonator, if equipped
6. Exhaust tail pipe, if equipped
7. Exhaust hangers
8. Exhaust heat shields

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

1. Platinum (Pt)
2. Palladium (Pd)
3. 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.

Scheme 23

See also:
• ENGINE MOUNT STRUT (RIGHT) -- REPLACEMENT
• FUEL INJECTOR SIGHT SHIELD - REPLACEMENT
• ROTATING THE ENGINE FOR SERVICE ACCESS
• Symptoms - Engine Exhaust
• Exhaust System Description
• Restricted Exhaust