Engine Exhaust System: Removal & Installation Chevrolet TrailBlazer I

Installation Procedure

Scheme 16

Scheme 17

1. 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. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Install the exhaust manifold, NEW gasket and bolts. Tighten 2.1. Tighten the bolts a first pass to 15 N.m (11 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts. 2.1. Tighten the bolts a final pass to 25 N.m (18 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
3. Install the heat shield, and bolts to the exhaust manifold. Tighten Tighten the bolts to 9 N.m (80 lb in).
4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
5. Install the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .
6. Raise the vehicle.
7. Install the exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
8. Lower the vehicle.

Scheme 18

Scheme 19

1. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information.
2. Remove the exhaust manifold pipe nuts.
3. Lower the vehicle.
4. Remove the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .
5. Remove the heat shield bolts, and shield from the exhaust manifold.
6. Remove the exhaust manifold bolts, manifold, and gasket.
7. Discard the gasket.
8. Clean and inspect the exhaust manifold. Refer to EXHAUST MANIFOLD CLEANING AND INSPECTION .

Scheme 20

Scheme 21

1. 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. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Install the exhaust manifold, NEW gasket and bolts. Tighten 2.1. Tighten the bolts a first pass to 15 N.m (11 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts. 2.1. Tighten the bolts a final pass to 25 N.m (18 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
3. Install the heat shield, and bolts to the exhaust manifold. Tighten Tighten the bolts to 9 N.m (80 lb in).
4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
5. Install the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .
6. Raise the vehicle.
7. Install the exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
8. Lower the vehicle.

Scheme 22

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Scheme 24

1. Raise the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information.
2. Remove the nuts that secure the converter pipe to the exhaust manifold.
3. Remove the nuts that secure the converter pipe to the muffler.
4. Slide the catalytic converter out of the exhaust insulators and out of the vehicle.

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Scheme 27

1. Install the converter hangars into the exhaust insulators in order to secure the pipe to the vehicle. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Install the converter pipe to the muffler and secure the pipe with the nut. Tighten Tighten the converter pipe to muffler nuts to 45 N.m (33 lb ft).
3. Install the converter pipe to the exhaust manifold with the exhaust seal, and secure the pipe with the nuts. Tighten Tighten the converter pipe to the exhaust manifold to 50 N.m (37 lb ft).
4. Lower the vehicle.

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Scheme 32

1. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information. NOTE: Refer to «HEATED OXYGEN & OXYGEN SENSOR NOTICE»(ref-175132-S05726417092005041500000) in Cautions and Notices. NOTE: Refer to «EXCESSIVE FORCE & OXYGEN SENSOR NOTICE»(ref-175132-S25037785732005041500000) in Cautions and Notices.
2. Unscrew both front heated oxygen sensor (HO2S) sensors (1) from the catalytic converter.
3. Unscrew both rear HO2S sensors (2) from the catalytic converter.
4. Remove the transmission support.
5. Remove the rear propeller shaft. Refer to PROPELLER SHAFT REPLACEMENT - REAR in Propeller Shaft.
6. If equipped with four wheel drive (4WD), unbolt the front propeller shaft from the drive axle. Refer to PROPELLER SHAFT REPLACEMENT - FRONT in Propeller Shaft.
7. Place the propeller shaft on top of the pinion yoke.
8. Remove the exhaust muffler nuts.
9. Remove the left exhaust manifold pipe nuts.
10. Remove the right exhaust manifold pipe nuts.
11. Raise the transmission.
12. Remove the catalytic converter (1) by angling the outlet pipe toward the left side of the vehicle to gain the necessary clearance for removal.

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Scheme 37

1. Install the catalytic converter (1) in reverse order of removal by starting with the outlet pipe angled toward the left side of the vehicle.
2. Install the exhaust muffler nuts. Position the catalytic converter in the installed location before tightening the nuts. Tighten Tighten the nuts to 45 N.m (33 lb ft).
3. Install the right exhaust manifold pipe nuts. Position the catalytic converter in the installed location before tightening the nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
4. Install the left exhaust manifold pipe nuts. Tighten Tighten the nuts to 50 N.m (37 lb ft).
5. If equipped with 4WD, install the front propeller shaft to the drive axle. Refer to PROPELLER SHAFT REPLACEMENT - FRONT in Propeller Shaft.
6. Install the rear propeller shaft. Refer to PROPELLER SHAFT REPLACEMENT - REAR in Propeller Shaft.
7. Lower the transmission.
8. Install the transmission support. IMPORTANT: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an exhaust component and if for any reason the sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.
9. If reinstalling the old sensors, coat the threads with anti-seize compound GM P/N 12377953, or equivalent. NOTE: Refer to «COMPONENT FASTENER TIGHTENING NOTICE»(ref-175132-S27295026372005041500000) in Cautions and Notices. IMPORTANT: If the HO2S sensor is connected to the main wiring harness during installation. Rotate the HO2S sensor several turns counterclockwise before threading the HO2S sensor into the catalytic converter. This action of initially reverse winding of the pigtail wires will prevent a condition where the HO2S sensor pigtail wires become severely twisted or binding once the HO2S sensor is installed into the catalytic converter.
10. Install both front HO2S sensors (1) to the catalytic converter. Tighten Tighten the sensor to 42 N.m (31 lb ft).
11. Install both rear HO2S (2) to the catalytic converter. Tighten Tighten the sensor to 42 N.m (31 lb ft).

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Scheme 40

1. Raise and suitably support the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information.
2. Remove the frame brace (required on extended versions).
3. Remove the nuts that secure the muffler to the catalytic converter pipe. IMPORTANT: If there is damage to any part of the exhaust muffler assembly replace as an assembly.
4. Inspect the exhaust muffler and the front pipe of the exhaust muffler for any damage if it is to be reused.
5. Separate the muffler from the hanger insulators.
6. Remove the muffler.
7. If there is any damage aft of the exhaust muffler: 7.1. Suitably support the exhaust system. 7.2. Cut the exhaust pipe (1), where the damage is located. 7.3. Remove the damaged exhaust pipe and resonator.

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Scheme 42

1. If replacing the whole muffler assembly, carefully install the muffler into place on the vehicle and secure the exhaust hangars to the insulators. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Install the muffler to the catalytic converter pipe and secure the pipe with the nuts. Tighten Tighten the nuts to 45 N.m (33 lb ft).
3. If replacing exhaust aft of the muffler: 3.1. Connect exhaust to insulators as required. 3.2. Install exhaust pipe to muffler. Tighten Tighten the clamp nuts to 50 N.m (37 lb ft). 3.2. Remove the exhaust support.
4. Inspect the exhaust system for leaks and underbody contact.
5. Install the frame brace (required on extended versions).
6. Lower the vehicle.

Scheme 43

1. Raise the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information.
2. Remove the 5 bolts securing the heat shield to the floor panel studs.
3. Remove the heat shield from the vehicle.

Scheme 44

1. Place the catalytic converter heat shield onto the floor panel studs. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Secure the heat shield with the 5 bolts. Tighten Tighten the catalytic converter heat shield bolts to 7 N.m (62 lb in).
3. Lower the vehicle.

Scheme 45

Scheme 46

1. Remove the air cleaner resonator outlet duct. Refer to «AIR CLEANER RESONATOR OUTLET DUCT»(ref-159085-S05754353602003111400000) .
2. Remove the transmission filler tube stud nut from the A.I.R. adapter and move the filler out of the way.
3. Remove the oil level indicator tube. Refer to OIL LEVEL INDICATOR AND TUBE REPLACEMENT .
4. Remove the oxygen sensor from the exhaust manifold. Refer to «OXYGEN SENSORS (4.2L)»(ref-159085-S26001549372003111100000) .
5. Remove the 4 manifold heat shield nuts and remove the heat shield.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 47

1. Install the exhaust manifold heat shield with the 4 nuts. Tighten Tighten the exhaust manifold heat shield nuts to 10 N.m (89 lb in).
2. Install the oxygen sensor. Refer to «OXYGEN SENSORS (4.2L)»(ref-159085-S26001549372003111100000) .
3. Install the oil level indicator. Refer to OIL LEVEL INDICATOR AND TUBE REPLACEMENT .
4. Move the transmission filler tube back onto the stud and secure the tube with the nut. Tighten Tighten the transmission filler tube bracket nut to 10 N.m (89 lb in).
5. Install the air cleaner resonator outlet duct. Refer to «AIR CLEANER RESONATOR OUTLET DUCT»(ref-159085-S05754353602003111400000) .

Scheme 48

1. Remove the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .
2. Remove the heat shield bolts, and shield from the exhaust manifold.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 49

1. Install the heat shield, and bolts to the exhaust manifold. Tighten Tighten the bolts to 9 N.m (80 lb in).
2. Install the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .

Scheme 50

1. Remove the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .
2. Remove the heat shield bolts, and shield from the exhaust manifold.

Note. Refer to FASTENER NOTICE in Cautions and Notices.

Scheme 51

1. Install the heat shield, and bolts to the exhaust manifold. Tighten Tighten the bolts to 9 N.m (80 lb in).
2. Install the spark plugs. Refer to «SPARK PLUGS»(ref-159085-S02952502512003111400000) .

Scheme 52

1. Raise the vehicle. Refer to «LIFTING AND JACKING THE VEHICLE»(ref-188480-S19457848752005090300000) in General Information.
2. Remove the catalytic converter heat shield rear 2 bolts where the catalytic converter heat shield connects to the muffler heat shield.
3. Remove the remaining exhaust muffler heat shield bolts and remove the heat shield from the floor panel studs.

Scheme 53

1. Install the muffler heat shield to the floor panel studs placing the muffler heat shield under the rear part of the converter heat shield. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Secure the muffler heat shield with 5 bolts. Tighten Tighten the exhaust muffler heat shield bolts to 7 N.m (62 lb in).
3. Lower the vehicle.