Engine Exhaust System Cadillac Escalade GMT800

Scheme 1

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»(/cadillac/escalade/gmt800-2001-2006/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. For a detailed explanation, Refer to 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»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
2. Poor acceleration Refer to «RESTRICTED EXHAUST»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
3. Poor fuel economy Refer to «RESTRICTED EXHAUST»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
4. Excessive smoke (diesel) Refer to «RESTRICTED EXHAUST»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
5. Exhaust hissing noise Refer to Exhaust Leakage, See «Exhaust Leakage»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
6. Exhaust popping noise Refer to Exhaust Leakage, See «Exhaust Leakage»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
7. Exhaust rattle noise Refer to Exhaust Noise, See «Exhaust Noise»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
8. Loud exhaust noise Refer to Exhaust Noise, See «Exhaust Noise»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
9. Exhaust buzz, groan, hum noise Refer to Exhaust Noise, See «Exhaust Noise»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .

Test Description

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

1. 3. 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 heater oxygen sensor (HO2S) sensor may set a DTC. When finishing this diagnostic table, be sure to clear all codes.
2. 4. This step will isolate the catalytic converter from the remainder of the exhaust system.
3. 7. 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.

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Removal Procedure

1. Remove the ignition coils. Refer to Ignition Coil(s) Replacement in Engine Controls -4.8L, 5.3L, and 6.0L.
2. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
3. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
4. Remove the exhaust manifold pipe nuts.
5. Lower the vehicle.
6. Remove the exhaust manifold bolts, manifold, and gasket.
7. Discard the gasket.
8. Remove the heat shield bolts (3), and shield (2) from the exhaust manifold (1), if necessary.
9. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 4.8L, 5.3L, and 6.0L.

Scheme 6

Scheme 7

1. Install the heat shield (2), and bolts (3) to the exhaust manifold (1), if necessary. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolts to 9 N.m (80 lb in). Important: Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or On-Board Diagnostics (OBD) II system performance. The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material. Do not apply sealant to the first three threads of the bolt.
2. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
3. Install the exhaust manifold, NEW gasket and bolts. Tighten 3.1. Tighten the bolts a first pass to 15 N.m (15 lb ft). Tighten the exhaust manifold bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts. 3.2. Tighten the bolts a final pass to 25 N.m (18 lb ft). Tighten the exhaust manifold bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
5. Raise the vehicle.
6. Install the exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
7. Lower the vehicle.
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls -4.8L, 5.3L, and 6.0L.
9. Install the ignition coils. Refer to Ignition Coil(s) Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.

1. Remove the wheelhouse panel. Refer to WHEELHOUSE PANEL REPLACEMENT in Body Front End. Important: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug wire or the wire could be damaged.
2. Remove the spark plug wires from the spark plugs and ignition coils.
3. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L.
4. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
5. Remove the exhaust manifold heat shield bolts and nuts.
6. Remove the exhaust manifold heat shield.
7. Lower the vehicle.
8. Remove the exhaust manifold bolt and nuts.
9. Remove the exhaust manifold.
10. Remove and discard the exhaust manifold gasket.
11. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 8.1L.

Installation Procedure

1. Install a NEW exhaust manifold gasket.
2. Install the exhaust manifold.
3. Install the exhaust manifold bolt and nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolt to 35 N.m (26 lb ft). Tighten the nuts to 16 N.m (12 lb ft).
4. Raise the vehicle.
5. Install the exhaust manifold heat shield.
6. Install the exhaust manifold heat shield bolts and nuts. Tighten Tighten the bolts and nuts to 25 N.m (18 lb ft).
7. Lower the vehicle.
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls -8.1L Important: Fully install the spark plug wire by pushing on the exposed end of the spark plug boot. Do not push the spark plug wire on to the spark plug by using the metal heat shield.
9. Install the spark plug wires to the spark plugs and ignition coils.
10. Install the wheelhouse panel. Refer to WHEELHOUSE PANEL REPLACEMENT in Body Front End.

1. Remove the ignition coils. Refer to Ignition Coil(s) Replacement in Engine Controls -4.8L, 5.3L, and 6.0L.
2. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
3. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
4. Remove the exhaust manifold pipe nuts.
5. Lower the vehicle.
6. Remove the exhaust manifold bolts, manifold, and gasket.
7. Discard the gasket.
8. Remove the heat shield bolts (1), and shield (2) from the exhaust manifold (1), if necessary.
9. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 4.8L, 5.3L, and 6.0L.

Scheme 8

Scheme 9

1. Install the heat shield (2), and bolts (1) to the exhaust manifold (1), if necessary. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolts to 9 N.m (80 lb in). Important: Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or On-Board Diagnostics (OBD) II system performance. The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material. Do not apply sealant to the first three threads of the bolt.
2. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.
3. Install the exhaust manifold, NEW gasket and bolts. Tighten 3.1. Tighten the bolts a first pass to 15 N.m (11 lb ft). Tighten the exhaust manifold bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts. 3.2. Tighten the bolts a final pass to 25 N.m (18 lb ft). Tighten the exhaust manifold bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the front of the right cylinder head.
5. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls -4.8L, 5.3L, and 6.0L.
6. Install the ignition coils. Refer to Ignition Coil(s) Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
7. Raise the vehicle.
8. Install the exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
9. Lower the vehicle.

1. Remove the wheelhouse panel. Refer to WHEELHOUSE PANEL REPLACEMENT in Body Front End.
2. Remove the oil level indicator tube. Refer to Oil Level Indicator and Tube Replacement in Engine Mechanical - 8.1L. Important: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug or the wire could be damaged.
3. Remove the spark plug wires from the spark plugs and ignition coils.
4. Remove the engine coolant temperature (ECT) sensor.
5. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls -8.1L.
6. Remove the exhaust gas recirculation (EGR) pipe nuts (5) from the exhaust manifold.
7. Remove the EGR pipe bracket bolt (4).
8. Remove and discard the EGR pipe gasket.
9. Reposition the EGR pipe (2).
10. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
11. Remove the exhaust manifold heat shield bolts and nuts.
12. Remove the exhaust manifold heat shield.
13. Lower the vehicle.
14. Remove the exhaust manifold bolt and nuts.
15. Remove the exhaust manifold.
16. Remove and discard the exhaust manifold gasket.
17. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 8.1L.

Scheme 10

1. Install a NEW exhaust manifold gasket.
2. Install the exhaust manifold.
3. Install the exhaust manifold bolt and nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolt to 35 N.m (26 lb ft). Tighten the nuts to 16 N.m (12 lb ft).
4. Raise the vehicle.
5. Install the exhaust manifold heat shield.
6. Install the exhaust manifold heat shield bolts and nuts. Tighten Tighten the bolts and nuts to 25 N.m (18 lb ft).
7. Lower the vehicle.
8. Position the EGR (2).
9. Install a NEW EGR pipe gasket.
10. Install the EGR pipe bracket bolt (4). Tighten Tighten the bolt to 50 N.m (37 lb ft).
11. Install the EGR pipe nuts (5) to the exhaust manifold. Tighten Tighten the nuts to 30 N.m (22 lb ft).
12. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L
13. Coat the threads of the sensor with sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent.
14. Install the ECT sensor. Tighten Tighten the sensor to 20 N.m (15 lb ft). Important: Fully install the spark plug wires by pushing on the exposed end of the spark plug boot. Do not push the spark plug wire on to the spark plug by using the metal heat shield.
15. Install the spark plug wires to the spark plugs and ignition coils.
16. Install the oil level indicator tube. Refer to Oil Level Indicator and Tube Replacement in Engine Mechanical - 8.1L.
17. Install the wheelhouse panel. Refer to WHEELHOUSE PANEL REPLACEMENT in Body Front End.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Support the transmission with a suitable transmission jack.
3. Remove the transmission mount to transmission support nuts.
4. Raise the transmission off of the transmission support.
5. Remove the transmission support crossmember bolts.
6. Remove the transmission support crossmember.
7. Remove the exhaust muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
8. Remove the clip around the engine harness and the oxygen sensor pigtail.
9. Disconnect the connector position assurance (CPA) retainer.
10. Disconnect the oxygen sensor electrical connector.
11. Remove the oxygen sensor.
12. Remove the exhaust manifold pipe nuts.
13. Using the transmission jack, lower the transmission slightly.
14. Remove the exhaust manifold pipe.
15. Discard the exhaust manifold pipe seal.

1. Install a NEW exhaust manifold pipe seal to the exhaust manifold pipe.
2. Install the exhaust manifold pipe.
3. Using the transmission jack, raise the transmission.
4. Install the exhaust manifold pipe nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the nuts to 50 N.m (39 lb ft).
5. If the old oxygen sensor is being reused, apply anti-seize compound GM P/N 12377953 or equivalent to the threads.
6. Install the oxygen sensor. Tighten Tighten the sensor to 42 N.m (31 lb ft).
7. Connect the oxygen sensor electrical connector.
8. Connect the CPA retainer.
9. Install the clip around the engine harness and the oxygen sensor pigtail.
10. Install the exhaust muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
11. Install the transmission support crossmember.
12. Install the transmission support crossmember bolts. Tighten Tighten the bolts to 95 N.m (70 lb ft).
13. Lower the transmission onto the transmission support.
14. Install the transmission mount to transmission support nuts. Tighten Tighten the nuts to 40 N.m (30 lb ft).
15. Remove the transmission jack.
16. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Disconnect the connector position assurance (CPA) retainer.
3. Disconnect the oxygen sensor electrical connector (1).
4. Support the catalytic converter or exhaust manifold pipe with adjustable jackstands.
5. Remove the right exhaust manifold pipe nuts.
6. Remove the left exhaust manifold pipe nuts.
7. Remove the exhaust hanger mounting bracket bolts.
8. Lower the catalytic converter or exhaust manifold pipe using the adjustable jackstands.
9. Remove the exhaust manifold pipe seal(s).

1. Install the exhaust manifold pipe seal(s).
2. Raise the catalytic converter or exhaust manifold pipe using the adjustable jackstands.
3. Install the exhaust hanger mounting bracket bolts.
4. Install the left exhaust manifold pipe nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the exhaust pipe hanger bracket bolts to 12 N.m (106 lb in). Tighten the exhaust manifold pipe nuts to 50 N.m (39 lb ft).
5. Install the right exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (39 lb ft).
6. Connect the oxygen sensor electrical connector (1).
7. Connect the CPA retainer.
8. Remove the adjustable jackstands from catalytic converter or exhaust manifold pipe.
9. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Support the transmission with a suitable transmission jack.
3. Remove the transmission mount to transmission support nuts.
4. Raise the transmission off of the transmission support.
5. Remove the transmission support crossmember bolts and nuts.
6. Remove the transmission support crossmember.
7. Remove the clip from around the engine harness and the oxygen sensor pigtail.
8. Disconnect the connector position assurance (CPA) retainers.
9. Disconnect the oxygen sensor electrical connectors.
10. Unclip the oxygen sensor electrical connectors from the following: Hose clip Transmission crossmember
11. Disconnect the CPA retainers.
12. Disconnect the oxygen sensor electrical connectors (1, 2).
13. Remove the left exhaust manifold pipe nuts.
14. Remove the right exhaust manifold pipe nuts.
15. Remove the exhaust muffler nuts.
16. Remove the catalytic converter.
17. Remove the oxygen sensors if the catalytic converter is to be replaced.

Scheme 11

1. If the catalytic converter was replaced, perform the following: Apply anti-seize compound 1.1. GM P/N 12377953 or equivalent to the threads of the old oxygen sensors. 1.2. Install the oxygen sensors. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the oxygen sensors to 42 N.m (31 lb ft).
2. Install the catalytic convertor.
3. Install NEW exhaust manifold pipe seals to the exhaust manifolds.
4. Install the right exhaust manifold pipe nuts until sung.
5. Install the left exhaust manifold pipe nuts until snug.
6. Tighten the right and left exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (39 lb ft).
7. Install the exhaust muffler nuts. Tighten Tighten the nuts to 40 N.m (30 lb ft).
8. Connect the oxygen sensor electrical connectors (1, 2).
9. Connect the CPA retainers.
10. Clip the oxygen sensors electrical connectors to the following: Hose clip Transmission crossmember
11. Connect the oxygen sensor electrical connectors.
12. Connect the CPA retainers.
13. Install the clip around the engine harness and the oxygen sensor pigtail.
14. Install the transmission support crossmember.
15. Install the transmission support crossmember bolts and nuts. Tighten Tighten the bolts to 95 N.m (70 lb ft).
16. lower the transmission onto the transmission support.
17. Install the transmission mount to transmission support nuts. Tighten Tighten the nuts to 40 N.m (30 lb ft).
18. Remove the transmission jack.
19. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
3. Disconnect the connector position assurance (CPA) retainers.
4. Disconnect the oxygen sensor electrical connectors (1, 2).
5. Remove the left exhaust manifold pipe nuts.
6. Remove the catalytic converter.
7. Slide the catalytic converter hanger out of the exhaust pipe hanger bracket.
8. Remove the oxygen sensors if the catalytic converter is to be replaced.

Scheme 12

1. If the catalytic converter was replaced, perform the following: 1.1. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensors. 1.2. Install the oxygen sensors. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the sensors to 42 N.m (31 lb ft).
2. Install a NEW exhaust seal to the exhaust manifold.
3. Install the catalytic converter. Slide the catalytic converter hanger into the exhaust pipe hanger bracket.
4. Install the left exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (39 lb ft).
5. Connect the oxygen sensor electrical connectors (1, 2).
6. Connect the CPA retainers.
7. Install the muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
8. Lower the vehicle.

1. Remove the exhaust manifold pipe. Refer to «EXHAUST MANIFOLD PIPE REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
2. Remove the catalytic converter. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
3. If equipped with a 4L80E transmission, remove the exhaust pipe hanger bracket bolts.
4. If equipped with a 4L60E transmission, remove the exhaust pipe hanger bracket bolts.
5. Remove the exhaust manifold pipe bracket.

1. Install the exhaust manifold pipe hanger bracket.
2. If equipped with a 4L60E transmission, install the exhaust pipe hanger bracket bolts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolts to 12 N.m (106 lb in).
3. If equipped with a 4L80E transmission, install the exhaust pipe hanger bracket bolts. Tighten Tighten the bolts to 12 N.m (106 lb in).
4. Install the catalytic converter. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
5. Install the exhaust manifold pipe. Refer to «EXHAUST MANIFOLD PIPE REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .

Muffler Replacement (4.8L and 5.3L Engines)

Tools Required: J 38185 Hose Clamp Pliers

Scheme 13

Scheme 14

1. Remove the spare tire wheel stowage lock cylinder.
2. Remove the spare tire from the hoist.
3. Remove the rear tires and wheels. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
4. If vehicle is equipped with regular production option (RPO) Z55, disconnect the following right side chassis harness electrical connectors: Electronic suspension rear position sensor (1) Rear shock (2)
5. If vehicle is equipped with RPO Z55, disconnect the following left side chassis harness electrical connectors: Electronic suspension rear position sensor (1) Rear shock (2) Important: Do not attempt to pry the rear suspension sensor link rod from the rear position sensor ball stud.
6. Remove the left and right sensor link rods from the sensors, perform the following: 6.1. Support the sensor lever with your hand 6.2. Twist the link rod in order to remove it from the ball stud
7. Install adjustable jack stands under the rear axle.
8. Remove the rear axle vent hose from the rear axle, if necessary.
9. Remove the vent hose swivel clip from the rear brake crossover pipe.
10. Remove the rear shock absorbers lower bolts and nuts.
11. Lower the rear axle slightly, using the adjustable jack stands, in order to remove the muffler.
12. Remove the exhaust muffler nuts.
13. Remove the muffler from the insulators.

Scheme 15

Scheme 16

1. Apply lubricant to the exhaust insulators in order to aid in installation.
2. Install the muffler to the insulators.
3. Install the exhaust muffler nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the nuts to 40 N.m (30 lb ft).
4. Raise the rear axle, using the adjustable jackstands.
5. Install the lower bolts and nuts to the rear shock absorbers. Tighten Tighten the bolts to 95 N.m (70 lb ft).
6. Remove the adjustable jack stands from under the rear axle.
7. Install the vent hose swivel clip to the rear brake crossover pipe.
8. Install the rear axle vent hose to the rear axle, if necessary.
9. If vehicle is equipped with RPO Z55, install the left and right sensor link rods to the sensors.
10. Using J 38185 install the link rods to the ball studs on the sensor levers.
11. If vehicle is equipped with RPO Z55, connect the following left side chassis harness electrical connectors: Electronic suspension rear position sensor (1) Rear shock (2)
12. If vehicle is equipped with RPO Z55, connect the following right side chassis harness electrical connectors: Electronic suspension rear position sensor (1) Rear shock (2)
13. Install the rear tires and wheels. Refer to TIRE AND WHEEL REMOVAL AND INSTALLATION in Tires and Wheels.
14. Install the spare tire to the hoist.
15. Install the spare tire wheel stowage lock cylinder.

Scheme 17

Scheme 18

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Unclip the oxygen sensor connector from the frame.
3. Disconnect the connector position assurance (CPA) retainer.
4. Disconnect the oxygen sensor electrical connector.
5. Unclip the oxygen sensor connector from the support.
6. Disconnect the CPA retainer.
7. Disconnect the oxygen sensor electrical connector.
8. Unclip the oxygen sensor connector from the support.
9. Disconnect the CPA retainer.
10. Disconnect the oxygen sensor electrical connector.
11. If equipped with a 6.0L engine, perform the following: Unclip the oxygen sensor connector from the frame. Disconnect the CPA retainer. Disconnect the oxygen sensor electrical connector.
12. Remove the exhaust muffler nuts.
13. Loosen the exhaust pipe clamp.
14. With the aid of an assistant, support the exhaust muffler.
15. Remove the insulators from the frame hangers.
16. With the aid of an assistant, slide the muffler rearward in order to remove the muffler from the catalytic converter.
17. Remove the insulators from the muffler hangers.
18. Remove the exhaust manifold pipe gasket.
19. Remove the oxygen sensor if the muffler is being replaced.

Scheme 19

Scheme 20

Scheme 21

1. If the muffler was replaced reinstall the old oxygen sensor.
2. Apply anti-seize compound GM P/N 12377953 or equivalent to the threads of the old oxygen sensor.
3. Install the oxygen sensor. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the oxygen sensor to 42 N.m (31 lb ft). Important: Apply lubricant to the insulators to aid in installation.
4. Install the insulators to the muffler hangers.
5. Install a new exhaust manifold pipe gasket.
6. With the aid of an assistant, slide the muffler forward in order to install the muffler to the catalytic converter.
7. Install the insulators to the frame hangers.
8. Lower the vehicle.
9. Install the exhaust muffler nuts, until snug.
10. Tighten the exhaust pipe clamp bolt and muffler nuts. Tighten Tighten the nuts to 40 N.m (30 lb ft). Tighten the clamp to 40 N.m (30 lb ft).
11. If equipped with a 6.0L engine, perform the following: Connect the oxygen sensor electrical connector. Connect the CPA retainer. Clip the oxygen sensor connector to the frame.
12. Connect the oxygen sensor electrical connector.
13. Connect the CPA retainer.
14. Clip the oxygen sensor connector to the support.
15. Connect the oxygen sensor electrical connector.
16. Connect the CPA retainer.
17. Clip the oxygen sensor connector to the support.
18. Connect the oxygen sensor electrical connector.
19. Connect the CPA retainer.
20. Clip the oxygen sensor connector to the frame.

1. Remove the exhaust manifold pipe, if necessary. Refer to «EXHAUST MANIFOLD PIPE REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
2. Remove the catalytic converter, if necessary. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
3. Remove the exhaust front heat shield nuts.
4. Remove the exhaust front heat shield from the studs.
5. Remove the exhaust heat shield nuts.
6. Remove the exhaust heat shield from the studs.

1. Install the exhaust heat shield to the studs.
2. Install the exhaust heat shield nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the nuts to 9 N.m (80 lb in).
3. Install the exhaust front heat shield to the studs.
4. Install the exhaust front heat shield nuts. Tighten Tighten the nuts to 9 N.m (80 lb in).
5. Install the catalytic converter, if necessary. Refer to «CATALYTIC CONVERTER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) or «CATALYTIC CONVERTER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
6. Install the exhaust manifold pipe, if necessary. Refer to «EXHAUST MANIFOLD PIPE REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .

1. Remove the exhaust muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .
2. Remove the exhaust heat shield bolts.
3. Remove the exhaust heat shield.

1. Install the exhaust heat shield.
2. Install the exhaust heat shield bolts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the bolts to 9 N.m (80 lb in).
3. Install the exhaust muffler. Refer to «MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system__muffler-replacement-48l-and-53l-engines) or «MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES)»(/cadillac/escalade/gmt800-2001-2006/remont/exhaust/#engine-exhaust-system) .

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the engine shield bolts and shield, if necessary.
3. Remove the exhaust heat shield nuts.
4. Remove the exhaust heat shield (1, 3) from the dash panel studs.

1. Install the exhaust heat shield (1, 3) to the dash panel studs.
2. Install the exhaust heat shield nuts. NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. Tighten Tighten the nuts to 9 N.m (80 lb in).
3. Install the engine shield and bolts, if necessary. Tighten Tighten the bolts to 20 N.m (15 lb ft).
4. Lower the vehicle.

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. 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.

Scheme 22

Scheme 23

See also:
• SYMPTOMS - ENGINE EXHAUST
• EXHAUST SYSTEM DESCRIPTION
• RESTRICTED EXHAUST
• MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES)