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Engine Exhaust System Chevrolet Colorado I

Exhaust 1 illustration ~3000 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Catalytic Converter Nut50 N.m37 lb ft
Exhaust Manifold Bolt
First Pass20 N.m15 lb ft
Second Pass20 N.m15 lb ft
Final Pass20 N.m15 lb ft
Exhaust Manifold Heat Shield Nut10 N.m89 lb in
Heat Shield Nut9 N.m80 lb in
Leaf Spring Bolt and Nut85 N.m63 lb ft
Lower Shock Absorber Bolt and Nut95 N.m70 lb ft
Muffler Nut45 N.m33 lb ft
Transmission Filler Tube Bracket Nut12.5 N.m111 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/colorado/i-2004-2012/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/colorado/i-2004-2012/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) .

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/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  2. Poor acceleration-Refer to «Restricted Exhaust»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  3. Poor fuel economy-Refer to «Restricted Exhaust»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  4. Excessive smoke-diesel-Refer to «Restricted Exhaust»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  5. Exhaust hissing noise-Refer to «Exhaust Leakage»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
  6. Exhaust popping noise-Refer to «Exhaust Leakage»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system__exhaust-leakage) .
  7. Exhaust rattle noise-Refer to «Exhaust Noise»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise) .
  8. Loud exhaust noise-Refer to «Exhaust Noise»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise)
  9. Exhaust buzz, groan, hum noise-Refer to «Exhaust Noise»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system__exhaust-noise) .

Special Tools

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

Diagnostic Aids

CAUTIONRefer to Hot Exhaust System Caution .

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 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 . See «Special Tools»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) . Removing the heated oxygen sensor (HO2S) 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 diagnostic procedure on the opposite exhaust pipe.
StepActionValue(s)YesNo
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 system equipped with dual exhaust?Go to Diagnostic AidsGo to Step 4
4Remove the heated oxygen sensor (HO2S) that is in front of the catalytic converter. Refer to Heated Oxygen Sensor 1 Replacement or Heated Oxygen Sensor 1 Replacement Install the J 35314-A Exhaust Back Pressure Gage in place of the HO2S sensor. See Special Tools . Start the engine. Increase and monitor the engine speed at 2,500 RPM. Observe the exhaust system back pressure reading on the gage. Does the reading exceed the specified value?9 kPa (1.25 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 . Re-install the HO2S sensor. Refer to Heated Oxygen Sensor 1 Replacement or Heated Oxygen Sensor 1 Replacement . Remove the post-catalyst HO2S sensor. Refer to Heated Oxygen Sensor 2 Replacement or Heated Oxygen Sensor 2 Replacement . Install the J 35314-A in place of the post HO2S sensor. See Special Tools . Start the engine. Increase and monitor the engine speed at 2,500 RPM. Observe the exhaust system back pressure reading on the gage. Does the reading exceed the specified value?9 kPa (1.25 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 Exhaust Manifold Replacement (LLV) or Exhaust Manifold Replacement (LLR) or Catalytic Converter Replacement (LLV/LLR - w/2WD) or Catalytic Converter Replacement (LLV/LLR - w/4WD) . Did you find and correct the condition?Go to Step 8
8Remove the J 35314-A . See Special Tools . Reinstall the applicable HO2S sensor. Refer to the following: Heated Oxygen Sensor 1 Replacement Heated Oxygen Sensor 2 Replacement Heated Oxygen Sensor 1 Replacement Heated Oxygen Sensor 2 Replacement 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

ConditionAction
CAUTION: Refer to Hot Exhaust System Caution . 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 System Insulator, Hanger, Bracket Replacement .
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 Catalytic converter to exhaust manifold Catalytic converter to mufflerReplace the leaking seal or gasket. Refer to the following: Exhaust Manifold Replacement (LLV) or Exhaust Manifold Replacement (LLR) Exhaust Seal Replacement
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 Exhaust Manifold Replacement (LLV) or Exhaust Manifold Replacement (LLR) .
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, if equipped. Refer to Muffler Replacement (LLV/LLR) .
CAUTION
Refer to Hot Exhaust System Caution .

Exhaust Leakage

Exhaust Noise

ConditionAction
CAUTION: Refer to Hot Exhaust System Caution . 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, i.e. buzz, groan, hum.Refer to Symptoms - Engine Exhaust prior to beginning this table.
Popping or hissing noiseExhaust leak - Refer to Exhaust Leakage .
Loud exhaustCompare to a known good vehicle. Inspect for a damaged or failed muffler. Replace the faulty muffler. Refer to Muffler Replacement (LLV/LLR) .
External rattle or vibration noiseInspect for a bent or loose hanger, or loose heat shield. Inspect for a exhaust pipe causing interference. Repair or replace the faulty hanger, or heat shield. Refer to the following: Exhaust System Insulator, Hanger, Bracket Replacement Exhaust Manifold Heat Shield Replacement (LLV) Exhaust Manifold Heat Shield Replacement (LLR) Catalytic Converter Heat Shield Replacement Exhaust Pipe Heat Shield Replacement Exhaust Muffler Heat Shield Replacement
Internal rattleTest the components by tapping with a rubber mallet to confirm a rattle. Replace the faulty catalytic converter, or muffler. Refer to Catalytic Converter Replacement (LLV/LLR - w/2WD) or Catalytic Converter Replacement (LLV/LLR - w/4WD) or Muffler Replacement (LLV/LLR) .
CAUTION
Refer to Hot Exhaust System Caution .

Exhaust Noise

Removal Procedure

CAUTIONRefer to Exhaust Service Caution .
  1. Remove the exhaust seal. Refer to «Exhaust Seal Replacement»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  2. Remove the exhaust manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement (2.9L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Heat Shield Replacement (3.7L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  3. Remove the exhaust manifold bolts.
  4. Remove the exhaust manifold and the gasket from the engine. Discard the gasket.

Installation Procedure

  1. Place a NEW exhaust manifold gasket on to the cylinder head.
  2. Position the exhaust manifold to the cylinder head.
  3. Apply threadlock GM P/N 12345493 (Canadian P/N 10953488) to the exhaust manifold bolt threads.
  4. Install the exhaust manifold bolts.
  5. Tighten the exhaust manifold bolts in sequence. Tighten: Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft).
  6. Install the exhaust manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement (2.9L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Heat Shield Replacement (3.7L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  7. Install the exhaust seal. Refer to «Exhaust Seal Replacement»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
CAUTIONRefer to Exhaust Service Caution .
  1. Remove the exhaust seal. Refer to «Exhaust Seal Replacement»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  2. Remove the exhaust manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement (2.9L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Heat Shield Replacement (3.7L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  3. Remove the exhaust manifold bolts.
  4. Remove the exhaust manifold and the gasket from the engine. Discard the gasket.
  1. Place a NEW exhaust manifold gasket on to the cylinder head.
  2. Position the exhaust manifold to the cylinder head.
  3. Apply threadlock GM P/N 12345493 (Canadian P/N 10953488) to the exhaust manifold bolt threads.
  4. Install the exhaust manifold bolts.
  5. Tighten the exhaust manifold bolts in sequence. Tighten: Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft). Tighten the exhaust manifold bolts in sequence to 20 N.m (15 lb ft).
  6. Install the exhaust manifold heat shield. Refer to «Exhaust Manifold Heat Shield Replacement (2.9L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) or «Exhaust Manifold Heat Shield Replacement (3.7L)»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
  7. Install the exhaust seal. Refer to «Exhaust Seal Replacement»(/chevrolet/colorado/i-2004-2012/remont/exhaust/#engine-exhaust-system) .
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Remove the 3 nuts attaching the catalytic converter to the exhaust manifold.
  3. Position the exhaust system rearward, enough to allow clearance to remove the seal.
  4. Remove the exhaust manifold seal from the exhaust manifold flange. Discard the seal.
  1. Install the NEW seal to the exhaust manifold flange.
  2. Position the catalytic converter to the exhaust manifold.
  3. Install the 3 nuts attaching the catalytic converter to the exhaust manifold. Tighten: Tighten the catalytic converter nuts to 50 N.m (37 lb ft).
  4. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Disconnect the heated oxygen sensor (HO2S) at the sensor pigtail (3).
  3. Remove the HO2S if replacement is necessary. Refer to «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 2.9L engine or «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 3.7L engine.
  4. Remove the nuts securing the muffler to the catalytic converter.
  5. Position the muffler rearward, enough to allow the studs located in the front to clear the catalytic converter pipe flange.
  6. Remove the 3 nuts attaching the catalytic converter to the exhaust manifold.
  7. Lower the catalytic converter from the vehicle.
  8. Remove the exhaust manifold seal from the exhaust manifold flange. Discard the seal.
  1. Install the NEW seal to the exhaust manifold flange.
  2. Position the catalytic converter to the exhaust manifold.
  3. Install the 3 nuts attaching the catalytic converter to the exhaust manifold. Do not tighten at this time.
  4. Align the catalytic converter with the studs located in the front of the muffler.
  5. Install the 2 nuts securing the muffler to the catalytic converter. Tighten: Tighten the muffler nuts by hand until each contacts the metal flange. Tighten the muffler nuts to 45 N.m (33 lb ft). Tighten the catalytic converter nuts previously installed in step 3 to 50 N.m (37 lb ft).
  6. Install the HO2S if previously removed. Refer to «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 2.9L engine or «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 3.7L engine.
  7. Connect the HO2S at the sensor pigtail (3).
  8. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Remove the right torsion bar. Refer to «Torsion Bar Replacement»(/chevrolet/colorado/i-2004-2012/remont/suspension-front/#front-suspension-system) .
  2. Disconnect the heated oxygen sensor (HO2S) at the sensor pigtail (3).
  3. Remove the HO2S if replacement is necessary. Refer to «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 2.9L engine or «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 3.7L engine.
  4. Remove the nuts securing the muffler to the catalytic converter.
  5. Position the muffler rearward enough to allow the studs located in the front to clear the catalytic converter pipe flange.
  6. Remove the 3 nuts attaching the catalytic converter to the exhaust manifold.
  7. Lower the catalytic converter from the vehicle.
  8. Remove the exhaust manifold seal from the exhaust manifold flange. Discard the seal.
  1. Install the NEW seal to the exhaust manifold flange.
  2. Position the catalytic converter to the exhaust manifold.
  3. Install the 3 nuts attaching the catalytic converter to the exhaust manifold. Do not tighten at this time.
  4. Align the catalytic converter with the studs located in the front of the muffler.
  5. Install the 2 nuts securing the muffler to the catalytic converter. Tighten: Tighten the muffler nuts by hand until each contacts the metal flange. Tighten the muffler nuts to 45 N.m (33 lb ft). Tighten the catalytic converter nuts previously installed in step 3 to 50 N.m (37 lb ft).
  6. Install the HO2S if previously removed. Refer to «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 2.9L engine or «Heated Oxygen Sensor 2 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) for the 3.7L engine.
  7. Connect the HO2S at the sensor pigtail (3).
  8. Install the right torsion bar. Refer to «Torsion Bar Replacement»(/chevrolet/colorado/i-2004-2012/remont/suspension-front/#front-suspension-system) .

Exhaust System Insulator, Hanger, Bracket Replacement

Service the exhaust hangers individually in order to retain the support of the exhaust system.

CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Apply a soapy solution to the following in order to ease the removal of the hanger (1): The frame support bracket rod (2) The exhaust pipe hanger rod (3)
  3. Pry the exhaust pipe hanger (1) free from the following: The frame support bracket rod (2) The exhaust pipe hanger rod (3)
  1. Apply a soapy solution to the following in order to ease the installation of the hanger (1): The frame support bracket rod (2) The inner diameter of the exhaust pipe hanger (1) The exhaust pipe hanger rod (3)
  2. Press the exhaust pipe hanger (1) over the following: The frame support bracket rod (2) The exhaust pipe hanger rod (3)
  3. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Complete the following in order to gain clearance to remove the muffler: Remove the lower shock absorber nuts (9) and bolts (8). Remove the right rear leaf spring nut (2) and bolt (1). Wedge a block of wood (5) between the frame (4) and the rear axle (6).
  3. Remove the nuts securing the muffler to the catalytic converter.
  4. Apply a soapy solution to the exhaust pipe hanger rods (3) in order to ease the removal of the exhaust hangers (1).
  5. Pry the exhaust hangers (1) free from the exhaust pipe hanger rods (3).
  6. Complete the following in order to remove the muffler from the vehicle: Slide the muffler rearward from the catalytic converter. Rotate the muffler 90 degrees counterclockwise from the rear. Carefully remove the muffler rearward from the vehicle.
  1. Complete the following in order to install the muffler to the vehicle: With the muffler turned 90 degrees counterclockwise from the rear, carefully insert the muffler over the rear axle until the flange is near the catalytic converter. Rotate the muffler clockwise 90 degrees to the installed position. Slide the muffler forward into position, aligning the studs with the rear of the catalytic converter.
  2. Apply a soapy solution to the following in order to ease the installation of the hangers (1): The inner diameter of the exhaust pipe hanger (1) The exhaust pipe hanger rod (3)
  3. Press the exhaust pipe hangers (1) over the exhaust pipe hanger rods (3).
  4. Install the nuts securing the muffler to the catalytic converter. Tighten: Tighten the muffler nuts by hand until each contacts the metal flange. Tighten the muffler nuts to 45 N.m (33 lb ft).
  5. Remove the block of wood (5) from between the frame (4) and rear axle (6).
  6. Install the right rear leaf spring bolt (1) and nut (2). Tighten: Tighten the leaf spring bolt and nut to 85 N.m (63 lb ft).
  7. Install the lower shock absorber bolts (8) and nuts (9). Tighten: Tighten the lower shock absorber bolts and nuts to 95 N.m (70 lb ft).
  8. Inspect the exhaust system for leaks and underbody contact.
  9. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Remove the 5 nuts securing the heat shield to the floor panel.
  3. Remove the catalytic converter heat shield from the floor panel.
  1. Position the catalytic converter heat shield to the floor panel studs.
  2. Install the 5 nuts securing the heat shield to the floor panel. Tighten: Tighten the heat shield nuts to 9 N.m (80 lb in).
  3. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  3. If equipped with M30, remove the transmission filler tube bracket nut from the A.I.R. adapter, and position aside.
  4. Remove the heated oxygen sensor (HO2S) from the exhaust manifold. Refer to «Heated Oxygen Sensor 1 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  5. Remove the 3 nuts securing the heat shield to the exhaust manifold.
  6. Remove the exhaust manifold heat shield from the exhaust manifold.
  1. Position the exhaust manifold heat shield to the exhaust manifold.
  2. Apply anti-seize GM P/N 12371386 (Canadian P/N 993128) to the exhaust manifold heat shield nuts.
  3. Install the exhaust manifold heat shield nuts. Tighten: Tighten the nuts to 10 N.m (89 lb in).
  4. Install the HO2S to the exhaust manifold. Refer to «Heated Oxygen Sensor 1 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  5. Position the transmission filler tube to the A.I.R. adapter if previously removed.
  6. Install the transmission filler tube bracket nut. Tighten: Tighten the nut to 12.5 N.m (111 lb in).
  7. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  8. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
CAUTIONRefer to Exhaust Service Caution .
  1. Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
  2. Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
  3. If equipped with M30, remove the transmission filler tube bracket nut from the A.I.R. adapter, and position aside.
  4. Remove the heated oxygen sensor (HO2S) from the exhaust manifold. Refer to «Heated Oxygen Sensor 1 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
  5. Remove the 4 nuts securing the heat shield to the exhaust manifold.
  6. Remove the exhaust manifold heat shield from the exhaust manifold.
  1. Position the exhaust manifold heat shield to the exhaust manifold.
  2. Apply anti-seize GM P/N 12371386 (Canadian P/N 993128) to the exhaust manifold heat shield nuts.
  3. Install the exhaust manifold heat shield nuts. Tighten: Tighten the nuts to 10 N.m (89 lb in).
  4. Install the HO2S to the exhaust manifold. Refer to «Heated Oxygen Sensor 1 Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
  5. Position the transmission filler tube to the A.I.R. adapter if previously removed.
  6. Install the transmission filler tube bracket nut. Tighten: Tighten the nut to 12.5 N.m (111 lb in).
  7. Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-37l-introduction-2-of-2) .
  8. Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/colorado/i-2004-2012/remont/testing-diagnostics/#engine-control-system-fuel-system-29l-introduction-2-of-2) .
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Remove the 4 nuts securing the heat shield to the floor panel.
  3. Remove the exhaust pipe heat shield from the floor panel.
  1. Position the exhaust pipe heat shield to the floor panel studs.
  2. Install the 4 nuts securing the heat shield to the floor panel. Tighten: Tighten the heat shield nuts to 9 N.m (80 lb in).
  3. Lower the vehicle.
CAUTIONRefer to Exhaust Service Caution .
  1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/colorado/i-2004-2012/remont/hoistjack/#general-information) .
  2. Remove the 3 nuts securing the heat shield to the floor panel.
  3. Remove the exhaust muffler heat shield from the floor panel.
  1. Position the exhaust muffler heat shield to the floor panel studs.
  2. Install the 3 nuts securing the heat shield to the floor panel. Tighten: Tighten the heat shield nuts to 9 N.m (80 lb in).
  3. Lower the vehicle.

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 Illustration Tool Number/ Description J 35314-A Exhaust Back Pressure Gage

Scheme 1

Scheme 1: Special Tools
Scheme 1: Special Tools