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Engine Exhaust System Chevrolet Chevy Express G3500

Exhaust 2 illustrations ~2853 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Catalytic Converter Clamp - Right Side54 N.m40 lb ft
Catalytic Converter Pipe to Exhaust Manifold Nuts65 N.m48 lb ft
Catalytic Converter to Muffler Retaining Nuts48 N.m35 lb ft
Exhaust Hanger Bolts17 N.m13 lb ft
Exhaust Manifold Bolts First Pass - 4.3L15 N.m11 lb ft
Exhaust Manifold Bolts Second Pass - 4.3L30 N.m22 lb ft
Exhaust Manifold Bolts First Pass - 4.8L, 5.3L, 6.0L15 N.m11 lb ft
Exhaust Manifold Bolts Second Pass - 4.8L, 5.3L, 6.0L25 N.m18 lb ft
Exhaust Manifold Studs18 N.m13 lb ft
Heat Shield Bolts12 N.m106 lb in
Spark Plug Wire Support Bolts12 N.m106 lb in

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/chevy-express-g3500/1996-2012/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. For a detailed explanation, refer to «Strategy Based Diagnosis»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__strategy-based-diagnosis) in General Information.

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/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  2. Poor acceleration Refer to «Restricted Exhaust»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  3. Poor fuel economy Refer to «Restricted Exhaust»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  4. Excessive smoke (diesel) Refer to «Restricted Exhaust»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  5. Exhaust hissing noise Refer to «Exhaust Leakage»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
  6. Exhaust popping noise Refer to «Exhaust Leakage»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
  7. Exhaust rattle noise Refer to «Exhaust Noise»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise) .
  8. Loud exhaust noise Refer to «Exhaust Noise»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise) .
  9. Exhaust buzz, groan, hum noise Refer to «Exhaust Noise»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise) .

Diagnostic Aids

CAUTIONRefer to Hot Exhaust System Caution in Cautions and Notices.

If the vehicle is equipped with a 6.5 L diesel engine do not perform this diagnostic. The exhaust system does not have a location for installing the J 35314-A . See Special Tools and Equipment . Instead remove the suspect component, operate the vehicle, verify for improved performance. If performance is improved then replace the faulty component.

Test Description

Tools Required

J 35314-A Exhaust Back Pressure Gage. See Special Tools and Equipment .

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 . Removing the AIR check valve or HO2S sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes. See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  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 diagnostic procedure on the opposite exhaust pipe.
StepActionValue(s)YesNo
DEFINITION: If the vehicle is equipped with the 6.5L diesel engine, do not perform this test. For the 6.5L, remove the suspected component and road test for improved performance.
1Did you verify the customers complaint?Go to Step 2
2Did you review the exhaust symptoms diagnostic information and perform the necessary inspections?Go to Step 3Go to Symptoms - Engine Exhaust
3Is the vehicle equipped with a 6.5L diesel engine?Go to Diagnostic AidsGo to Step 4
4Remove the HO2S that is in front of and closest to the catalytic converter. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 in Engine Controls - 4.3L. Install the J 35314-A in place of the AIR check valve or HO2S sensor. See Special Tools and Equipment . Start the engine. Increase and monitor the engine speed at 2000 RPM. Observe the exhaust system back pressure reading on the gage. Does the reading exceed the specified value?14 kPa (2 psi)Go to Step 5Go to Step 8
5Turn the engine off and place the ignition in the lock position. Remove the J 35314-A . See Special Tools and Equipment . Re-install the HO2S sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 in Engine Controls - 4.3L. Remove the post-catalyst HO2S sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 in Engine Controls - 4.3L. Install the J 35314-A in place of the post HO2S sensor. See Special Tools and Equipment . Start the engine. Increase and monitor the engine speed at 2000 RPM. Observe the exhaust system back pressure reading on the gage. Does the reading exceed the specified value?14 kPa (2 psi)Go to Step 6Go to Step 7
6Inspect the exhaust system for the following conditions: Damage in the exhaust pipe Debris in the exhaust pipe Muffler or resonator internal failure Two-layer exhaust pipe separation Did you find and correct the condition?Go to Step 8
7Replace the catalytic converter. Refer to Catalytic Converter Replacement (4.3L) . Did you find and correct the condition?Go to Step 8
8Remove the J 35314-A . See Special Tools and Equipment . Reinstall the AIR check valve or HO2S sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 in Engine Controls - 4.3L. Clear any codes. Road test the vehicle in order to verify the repair. Did you correct the condition?System OKGo to Step 2

Restricted Exhaust

Exhaust Leakage

ProblemAction
CAUTION: Refer to Hot Exhaust System Caution in Cautions and Notices. 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 componentsAlign and tighten the exhaust system components to the specifications. Refer to Fastener Tightening Specifications . Ensure the exhaust hangers are in the proper locations and not loose. Refer to Exhaust Hanger Replacement (Dual Exhaust) .
Exhaust leaks at the following connections: Exhaust manifold to pipe Flanges Pipe clampsTighten 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 headReplace the leaking seal or gasket. Refer to the affected components procedure for service.
Irregularities at the mating surfaces on the flange connectionsRepair as required or replace the affected component. Refer to the affected components procedure for service.
Exhaust manifold cracked or brokenReplace the exhaust manifold. Refer to the following procedures: Exhaust Manifold Replacement - Left (4.3L) or Exhaust Manifold Replacement - Left (4.8L, 5.3L, 6.0L) Exhaust Manifold Replacement - Right (4.3L) or Exhaust Manifold Replacement - Right (4.8L, 5.3L, 6.0L)
Exhaust system component connection welds leakingReplace the leaking component. Refer to the affected component's procedure for service.
Muffler or resonator (if equipped) damaged or leaking at the seamsReplace the affected muffler or resonator. Refer to one of the following procedures: Muffler Replacement Resonator replacement
CAUTION
Refer to Hot Exhaust System Caution in Cautions and Notices.

Exhaust Leakage

Exhaust Noise

ConditionAction
CAUTION: Refer to Hot Exhaust System Caution in Cautions and Notices. 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).
Popping or hissing noiseExhaust leak
Loud exhaustCompare 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 noiseInspect 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 rattleTest the components by tapping with a rubber mallet to confirm a rattle. Replace the faulty catalytic converter or muffler. Refer to one of the following procedures: Muffler Replacement Catalytic Converter Replacement (4.3L)
CAUTION
Refer to Hot Exhaust System Caution in Cautions and Notices.

Exhaust Noise

Removal Procedure

  1. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  2. Disconnect the engine coolant temperature (ECT) gage sensor electrical connector.
  3. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  4. Remove the left front tire.
  5. Remove the left fender wheelhouse extension (1).
  6. Remove the catalytic converter assembly. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  7. Remove the EGR valve inlet pipe from the exhaust manifold.
  8. Remove the spark plug wires from the spark plugs.
  9. Remove the spark plug wire support bolts.
  10. Remove the spark plug wire support with the spark plug wires.
  11. Remove the spark plugs.
  12. Remove the exhaust manifold, gaskets and the spark plug wire shields from underneath the vehicle.
  13. Clean all gasket surfaces.

Installation Procedure

  1. Sub-assemble the NEW gaskets, the spark plug wire shields, and the bolts to the exhaust manifold.
  2. Ensure that the exhaust manifold bolts are held in place by the tabs on the exhaust manifold gaskets.
  3. Install the exhaust manifold. Tighten: Tighten the exhaust manifold bolts - First Pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts - Second Pass to 30 N.m (22 lb ft).
  4. Install the spark plugs.
  5. Install the spark plug wires to the spark plugs.
  6. Install the spark plug wire support and bolts. Tighten: Tighten the spark plug wire support bolts to 12 N.m (106 lb in).
  7. Install the EGR valve inlet pipe to the exhaust manifold. Tighten: Tighten the EGR valve inlet pipe exhaust manifold nut to 30 N.m (22 lb ft).
  8. Install the catalytic converter assembly. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  9. Install the fender wheelhouse extension (1).
  10. Install the left front tire.
  11. Lower the vehicle.
  12. Connect the ECT gage sensor electrical connector.
  13. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the catalytic converter from the exhaust manifold. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  3. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  4. Disconnect the EGR valve pipe from the exhaust manifold if equipped.
  5. Remove the spark plug wires.
  6. Remove the exhaust manifold.
  7. Clean all sealing surfaces.
  1. Install the exhaust manifold. Tighten: Tighten the exhaust manifold bolts - First Pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts - Second Pass to 25 N.m (18 lb ft).
  2. Connect the EGR valve pipe to the manifold.
  3. Install the spark plug wires.
  4. Install the exhaust pipe to the exhaust manifold.
  5. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the right front tire.
  3. Remove the right fender wheelhouse extension (1).
  4. Disconnect the spark plug wires from the spark plugs.
  5. Remove the bolts and the spark plug wire support.
  6. Remove the starter. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  7. Remove the catalytic converter assembly. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  8. Remove the exhaust manifold bolts through the wheelhouse.
  9. Remove the exhaust manifold with the exhaust manifold gaskets and the spark plug wire shields from the engine.
  10. Clean all gasket surfaces.
  1. Sub-assemble the NEW gaskets, the spark plug wire shields, and the bolts to the exhaust manifold.
  2. Ensure that the exhaust manifold bolts are held in place by the tabs on the exhaust manifold gaskets.
  3. Install the exhaust manifold. Tighten: Tighten the exhaust manifold bolts - First Pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts - Second Pass to 30 N.m (22 lb ft).
  4. Install the catalytic converter assembly. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  5. Install the starter. Refer to «Starter Motor Replacement (4.8L, 5.3L, and 6.0L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) or «Starter Motor Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
  6. Install the spark plug wire support and bolts. Tighten: Tighten the spark plug wire support bolts to 12 N.m (106 lb in).
  7. Install the spark plug wires. Refer to «Spark Plug Wire Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
  8. Install the fender wheelhouse extension (1).
  9. Install the front tire. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/chevy-express-g3500/1996-2012/remont/wheel-tire-system/#tires-and-wheels__tire-and-wheel-removal-and-installation) in Tire and Wheels.
  10. Lower the vehicle.
  1. Remove the catalytic converter from the exhaust manifold. Refer to «Catalytic Converter Replacement (4.3L)»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  2. Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  3. Remove the oil level indicator tube. Refer to «Oil Level Indicator and Tube Removal»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-removal-installation-1-of-3-48l-53l-60l__oil-level-indicator-and-tube-removal) in Engine Mechanical - 4.8L, 5.3L and 6.0L.
  4. Remove the exhaust manifold, bolts and exhaust manifold.
  5. Clean all sealing surfaces.
  1. Install the exhaust manifold and bolts. Tighten: Tighten the exhaust manifold bolts - First Pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts - Second Pass to 25 N.m (18 lb ft).
  2. Install the oil level indicator tube. Refer to «Oil Level Indicator and Tube Removal»(/chevrolet/chevy-express-g3500/1996-2012/remont/mechanical/#engine-mechanical-removal-installation-1-of-3-48l-53l-60l__oil-level-indicator-and-tube-removal) in Engine Mechanical - 4.8L, 5.3L and 6.0L.
  3. Install the catalytic converter to the exhaust manifold.
  4. Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/chevy-express-g3500/1996-2012/remont/exteriorinterior-trim/#interior-trim) in Interior Trim.
  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the catalytic converter pipe to exhaust manifold flange nuts.
  3. Remove the catalytic converter pipe from the exhaust manifold.
  4. Remove and discard the seal.
  5. Inspect the exhaust manifold studs for damage.
  6. Remove any damaged studs.
  1. Install any studs that were removed. Tighten: Tighten the exhaust manifold studs to 18 N.m (13 lb ft).
  2. Install the catalytic converter pipe and NEW seal to the exhaust manifold.
  3. Install the catalytic converter pipe to exhaust manifold flange nuts. Tighten: Tighten the catalytic converter pipe to manifold flange bolts to 65 N.m (48 lb ft).
  4. Lower the vehicle.
  5. Inspect for any exhaust leaks and proper alignment of the exhaust system.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Disconnect the heated oxygen sensor (HO2S) electrical connections from catalytic converter pipe.
  3. Remove the exhaust hanger bolts and hanger from the transmission.
  4. Remove the nuts and the seals retaining the catalytic converter pipe to the exhaust manifolds.
  5. Remove the flange nuts from the catalytic pipe to the muffler.
  6. Remove the catalytic converter from the vehicle.
  7. Remove the oxygen sensors as necessary. Refer to «Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
  1. Install the oxygen sensors as necessary. Refer to «Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1»(/chevrolet/chevy-express-g3500/1996-2012/remont/testing-diagnostics/#engine-control-system-43l-introduction) in Engine Controls - 4.3L.
  2. Position the catalytic pipe to the vehicle.
  3. Install the retaining nuts to the front of the muffler. Do not tighten the nuts.
  4. Install the new seals, the nuts and the exhaust pipe flange to exhaust manifold. Tighten: Tighten the exhaust pipe flange to exhaust manifold nuts to 65 N.m (48 lb ft). Tighten the catalytic converter to muffler retaining nuts to 48 N.m (35 lb ft).
  5. Connect the HO2S electrical connections.
  6. Install the exhaust hanger and bolts to the transmission. Tighten: Tighten the bolts to 17 N.m (13 lb ft).
  7. Verify the exhaust system for proper clearance and the alignment of all components.
  8. Lower the vehicle.
  1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the exhaust hanger bolts from the transmission.
  3. Using a suitable pry bar, remove the applicable hanger pin attached to the pipe from the exhaust hanger insulator.
  4. Remove the hanger from the vehicle.
  1. Install the exhaust pipe hanger pins in the exhaust hanger insulator.
  2. Install the exhaust hanger to the transmission.
  3. Install the exhaust hanger bolts. Tighten: Tighten the exhaust hanger bolts to 17 N.m (13 lb ft).
  4. Verify the exhaust system for proper clearance and the alignment of all components.
  5. Lower the vehicle.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the nuts retaining the exhaust pipe flange to the catalytic converter pipe.
  3. Remove the nuts retaining the exhaust pipe flange to the muffler.
  4. Remove the exhaust pipe.
  5. Remove the both flange gaskets.
  1. Install new gaskets to the muffler flange and the catalytic converter pipe flange.
  2. Install the exhaust pipe.
  3. Install the nuts for the muffler to the exhaust pipe.
  4. Install the nuts for the catalytic converter pipe to exhaust pipe. Tighten: Tighten the flange nuts to 48 N.m (35 lb ft).
  5. Verify the exhaust system for proper clearance and the alignment of all components.
  6. Lower the vehicle.
CAUTIONRefer to Protective Goggles and Gloves Caution in Cautions and Notices.
CAUTIONRefer to Exhaust Service Caution in Cautions and Notices.
IMPORTANTThe muffler is serviced as one complete unit with an exhaust pipe and tail pipe. Some variations of vehicles may have an aftermarket tail pipe added. When the vehicle is raised on the hoist it must be raised by the frame to allow the rear axle to be lowered.
  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. If equipped with 4.3L engine with a single catalytic converter pipe, remove the nuts retaining the catalytic converter pipe from the muffler flange.
  3. If equipped with a 4.8L/5.3L/6.0L engine with dual catalytic converter pipes, loosen the clamp for the right catalytic converter.
  4. Remove the nuts retaining the left catalytic converter to the muffler flange.
  5. Remove the muffler assembly hanger pins from the exhaust hanger insulators. Due to the weight of the exhaust system it may take 2 people.
  6. Remove the muffler assembly by lifting over the rear axle and remove towards the front of the vehicle.
  1. Install the muffler assembly from the front of the vehicle by lifting over the rear axle. Due to the weight of the exhaust system it may take 2 people.
  2. Install the muffler assembly hanger pins to the exhaust hanger insulators.
  3. If equipped with a 4.3L engine, install the retaining nuts and new gasket to the front of the muffler. Tighten: Tighten the catalytic converter to muffler retaining nuts to 48 N.m (35 lb ft).
  4. If equipped with a 4.8L/4.3L/6.0L engine, install the right catalytic converter in the muffler. Tighten: Tighten the clamp nut to 54 N.m (40 lb ft).
  5. Install a new gasket and the nuts retaining the left catalytic converter to the muffler flange. Tighten: Verify that the exhaust system is properly aligned and tighten the right catalytic converter clamp to 54 N.m (40 lb ft). Tighten the catalytic converter to the muffler flange nuts to 48 N.m (35 lb ft).
  6. Lower the vehicle.

Tools Required

J 34940 Rivet Gun. See Special Tools and Equipment .

  1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Using a 1/4 inch (6 mm) drill bit, remove the rivets from the heat shields, as necessary.
  3. Remove the exhaust tailpipe heat shield from the vehicle.
  4. Remove the muffler heat shield.
  5. Remove the front exhaust pipe heat shield.
  1. Install the front exhaust pipe heat shield on the vehicle.
  2. Install the rivets on the heat shield using the J 34940 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  3. Install the muffler heat shield on the vehicle.
  4. Install the rivets on the heat shield using the J 34940 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  5. Install the exhaust tailpipe heat shield on the vehicle.
  6. Install the rivets on the heat shield using the J 34940 . See «Special Tools and Equipment»(/chevrolet/chevy-express-g3500/1996-2012/remont/exhaust/#engine-exhaust-system) .
  7. Lower the vehicle.
  1. Raise and suitably support the vehicle with safety stands. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
  2. Remove the exhaust system, as necessary.
  3. Remove the bolts retaining the heat shield.
  4. Remove the heat shield.
  1. Install the heat shield.
  2. Install the heat shield bolts. Tighten: Tighten the heat shield retainer bolt to 12 N.m (106 lb in).
  3. Install the exhaust system, as necessary.
  4. Remove the safety stands and lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/chevy-express-g3500/1996-2012/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.

Exhaust System Description

IMPORTANTUse 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. Platium (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.

Special Tools

Special Tools Illustration Tool Number/ Description J 34940 Rivet Gun J 35314-A/BT-8515/BT-8515A Exhaust Back Pressure Tester/Air Pump Adapter

Scheme 1

Scheme 1: Special Tools
Scheme 1: Special Tools

Scheme 2

Scheme 2
Scheme 2