Engine Mechanical - 5.3L: Overview Chevrolet TrailBlazer I

Test Description

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. The chirping noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed any further in this table.
2. 3. The noise may be an internal engine noise. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the chirping noise is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. Inspect the drive belt(s) for signs of pilling. Pilling is the small balls, pills, or strings in the drive belt grooves caused by the accumulation of rubber dust.
4. 6. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of an accessory drive component, or the pulley may be bent inward or outward from a previous repair. Test for a misaligned accessory drive pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure for that pulley.
5. 10. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed.
6. 12. Inspection of the accessory drive pulley(s) should include inspecting for bends, dents, or other damage to the pulley(s) that would prevent the drive belt(s) from seating properly in the pulley grooves or on the smooth surface of the pulley when the back side of the drive belt is used to drive the pulley.
7. 14. Replacing the drive belt(s) when it is not damaged or there is not excessive pilling will only be a temporary repair.

Scheme 32

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. The squeal may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further in this table
2. 3. The squeal may be an internal engine noise. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the squealing noise is related to the drive belt(s) or an accessory drive component. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. This test is to verify that an accessory drive component(s) does not have a seized bearing. With the belt(s) removed, test the bearings in the accessory drive component(s) for smooth operation. Also test the accessory drive component(s) with the engine operating by varying the load on the accessory drive component(s) to verify that the component(s) is operating properly.
4. 5. This test is to verify that the drive belt(s) tensioner(s) are not operating properly. If the drive belt tensioner(s) are not operating properly, proper belt tension may not be achieved to keep the drive belt(s) from slipping which could cause a squealing noise.
5. 6. This test is to verify that the drive belt(s) is not too long, which would prevent the drive belt tensioner(s) from operating properly. Also if the incorrect length drive belt(s) was installed, it may not be routed correctly and may be turning an accessory drive component in the incorrect direction.
6. 7. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of a accessory drive component, or the pulley may be bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure for that pulley.
7. 8. Inspect the accessory drive pulley(s) to verify that they are the correct diameter or width. Using a known good vehicle, compare the accessory drive pulleys.

Scheme 33

The number(s) below refer to the step(s) in the diagnostic table.

1. 3. This test is to verify that the whine is being caused by the accessory drive component(s). Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the whining noise is related to the accessory drive component. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
2. 4. This inspection should include checking the drive belt tensioner and the drive belt idler pulley bearings. The drive belt(s) may have to be installed and the accessory drive components operated separately by varying their loads. Refer to the suspected accessory drive component for the proper removal and installation procedure.

Scheme 34

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
2. 3. This test is to verify that the drive belt(s) is causing the rumbling. Rumbling may be confused with an internal engine noise due to the similarity in the description. Remove only one drive belt at a time if the vehicle has multiple drive belts. Operate the engine for a few seconds, this will verify if the rumbling noise is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. Inspect the drive belt(s) to ensure that the drive belt(s) is not the cause of the noise. Small cracks across the ribs of the drive belt(s) will not cause the noise. Belt separation is identified by the plys of the belt separating, this may be seen at the edge of the belt or felt as a lump in the belt.
4. 5. Small amounts of pilling is a normal condition and acceptable. When the pilling is severe the drive belt(s) does not have a smooth surface for proper operation.

Scheme 35

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This test is to verify that the vibration is present during diagnosing. Other vehicle components may cause a similar symptom such as the exhaust system, or the drivetrain.
2. 3. This test is to verify that the drive belt(s) or accessory drive components may be causing the vibration. Remove the drive belt(s) and operate the engine for a few seconds, this will verify if the vibration is related to the drive belt(s) or not. With the drive belt(s) removed the water pump will not operate and the engine may overheat. Also diagnostic trouble codes (DTCs) may set when the engine is operated with the drive belt(s) removed.
3. 4. The drive belt(s) may cause a vibration. While the drive belt(s) is removed this is the best time to inspect the condition of the drive belt(s).
4. 6. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed.
5. 8. This step should only be performed if the fan is driven by the drive belt. Inspect the engine cooling fan for bent, twisted, loose, or cracked blades. Inspect the fan clutch for smooth operation. Inspect for a bent fan shaft or bent mounting flange.
6. 9. Inspect the water pump drive shaft for being bent. Also inspect the water pump bearings for smooth operation and excessive play. Compare the water pump with a known, good water pump.
7. 10. Accessory drive component brackets that are bent, cracked, or loose may put an extra strain on that accessory drive component causing it to vibrate.

Scheme 36

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This inspection is to verify the condition of the drive belt(s). Damage may have occurred to the drive belt(s) when the drive belt(s) fell off the pulley. Inspect the drive belt(s) for cuts, tears, sections of ribs missing, or damaged belt plys.
2. 4. Misalignment of the accessory drive pulley(s) may be caused from improper mounting or incorrect installation of a accessory drive component, or the pulley may be bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found, refer to that accessory drive component for the proper removal and installation procedure of that pulley.
3. 5. Inspection of the accessory drive pulley(s) should include inspecting for bends, dents, or other damage that would prevent the drive belt from seating properly in the pulley grooves or on the smooth surface of a pulley when the back side of the drive belt(s) is used to drive the pulley.
4. 6. Accessory drive component brackets that are bent or cracked will also cause the drive belt(s) to fall off.
5. 7. Inspection of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed. Missing, loose, or incorrect fasteners may cause pulley misalignment from the accessory drive bracket(s) moving under load. Over tightening the fasteners may cause misalignment of the accessory component bracket(s).

Scheme 37

The number(s) below refer to the step(s) in the diagnostic table.

1. 2. This inspection is to verify that the drive belt(s) is correctly installed on all of the accessory drive pulleys. Wear on the drive belt(s) may be caused by mis-positioning the drive belt(s) by one or more grooves on a pulley(s).
2. 3. The installation of a drive belt(s) that is too wide or too narrow will cause wear on the drive belt(s). The drive belt(s) ribs should match all of the grooves on the pulleys.
3. 4. This inspection is to verify that the drive belt(s) is not contacting any part of the engine or body while the engine is operating. There should be sufficient clearance when the accessory drive components load varies. The drive belt(s) should not come in contact with an engine or a body component when snapping the throttle.

Scheme 38

Scheme 39

Note. Allowing the drive belt tensioner to snap into the free position may result in damage to the tensioner.

1. Remove the drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) or «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(ref-188498-S07121034902005090700000) .
2. Move the drive belt tensioner through its full travel. The movement should feel smooth. There should be no binding. The tensioner should return freely.
3. If any binding is observed, replace the drive belt tensioner. Refer to «DRIVE BELT TENSIONER REPLACEMENT - ACCESSORY»(ref-188498-S31672862162005090700000) or «DRIVE BELT TENSIONER REPLACEMENT - AIR CONDITIONING»(ref-188498-S36388622452005090700000) .
4. Install the drive belt. Refer to of «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) or «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(ref-188498-S07121034902005090700000) .

Scheme 40

Scheme 41

1. Loosen the air cleaner outlet duct clamps at the following locations: The throttle body The mass airflow/intake air temperature (MAF/IAT) sensor
2. Remove the outlet duct bolt.
3. Remove the air cleaner outlet duct.
4. Install a breaker bar with hex-head socket to the drive belt tensioner bolt.
5. Rotate the drive belt tensioner clockwise in order to relieve tension on the belt.
6. Remove the belt from the pulleys and the drive belt tensioner.
7. Slowly release the tension on the drive belt tensioner.
8. Remove the breaker bar and socket and from the drive belt tensioner bolt.
9. Clean and inspect the belt surfaces of all the pulleys.

Scheme 42

Scheme 43

1. Route the drive belt around all the pulleys except the idler pulley.
2. Install the breaker bar with hex-head socket to the belt tensioner bolt.
3. Rotate the belt tensioner clockwise in order to relieve the tension on the tensioner.
4. Install the drive belt under the idler pulley.
5. Slowly release the tension on the belt tensioner.
6. Remove the breaker bar and socket from the belt tensioner bolt.
7. Inspect the drive belt for proper installation and alignment.
8. Install the air cleaner outlet duct. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
9. Install the outlet duct bolt. Tighten Tighten the bolt to 10 N.m (89 lb in).
10. Tighten the air cleaner outlet duct clamps at the following locations: The throttle body The MAF/IAT sensor Tighten Tighten the screws to 7 N.m (62 lb in).

Scheme 44

1. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) .
2. Install a ratchet into the air conditioning (A/C) belt tensioner adapter opening.
3. Rotate the A/C belt tensioner clockwise in order to relieve tension on the belt.
4. Remove the A/C belt from the pulleys.
5. Slowly release the tension on the A/C belt tensioner.
6. Remove the ratchet from the A/C belt tensioner.
7. Clean and inspect the belt surfaces of all the pulleys.

Scheme 45

1. Install the A/C belt around the crankshaft balancer.
2. Install a ratchet into the A/C drive belt tensioner adapter opening
3. Rotate the A/C belt tensioner clockwise in order to relieve tension on the tensioner.
4. Install the A/C belt over the idler pulley.
5. Install the A/C belt around the A/C compressor pulley.
6. Slowly release the tension on the A/C belt tensioner.
7. Remove the ratchet from the A/C belt tensioner.
8. Inspect the A/C belt for proper installation and alignment.
9. Install the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) .

Scheme 46

1. Loosen the drive belt idler pulley bolt.
2. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) .
3. Remove the drive belt idler pulley and bolt.

Scheme 47

1. Install the drive belt idler pulley and bolt to the generator bracket. Snug the bolt finger tight.
2. Install the drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) . NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
3. Tighten the drive belt idler pulley bolt. Tighten Tighten the bolt to 50 N.m (37 lb ft).

Scheme 48

1. Remove the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) .
2. Remove the drive belt tensioner bolts.
3. Remove the drive belt tensioner.

Scheme 49

1. Install the drive belt tensioner.
2. Install the drive belt tensioner bolts. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
3. Tighten the drive belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft).
4. Install the accessory drive belt. Refer to «DRIVE BELT REPLACEMENT - ACCESSORY»(ref-188498-S29906989872005090700000) .

Scheme 50

1. Remove the air conditioning (A/C) drive belt. Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(ref-188498-S07121034902005090700000) .
2. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Remove the A/C belt tensioner bolts.
4. Remove the A/C belt tensioner.

Scheme 51

1. Install the A/C belt tensioner. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) in Cautions and Notices.
2. Install the A/C belt tensioner bolts. Tighten Tighten the bolts to 50 N.m (37 lb ft).
3. Lower the vehicle.
4. Install the A/C drive belt. Refer to «DRIVE BELT REPLACEMENT - AIR CONDITIONING»(ref-188498-S07121034902005090700000) .

Crankcase Ventilation System Description

A closed crankcase ventilation system is used in order to provide a more complete scavenging of crankcase vapors. Fresh air from the throttle body is supplied to the crankcase, mixed with blow-by gases, and then passed through a crankcase ventilation pipe/passage into the intake manifold.

Results of Incorrect Operation

A plugged PCV Pipe/passage way may cause

1. Rough idle
2. Stalling or slow idle speed
3. Oil leaks
4. Sludge in engine

Drive Belt System Description

The drive belt system consists of the following components

1. The drive belt
2. The drive belt tensioner
3. The drive belt idler pulley
4. The crankshaft balancer pulley
5. The accessory drive component mounting brackets
6. The accessory drive components The power steering pump, if belt driven The generator The A/C compressor, if equipped The engine cooling fan, if belt driven The water pump, if belt driven The vacuum pump, if equipped The air compressor, if equipped

The drive belt system may use 1 belt or 2 belts. The drive belt is thin so that it can bend backwards and has several ribs to match the grooves in the pulleys. There also may be a V-belt style belt used to drive certain accessory drive components. The drive belts are made of different types of rubbers - chloroprene or EPDM - and have different layers or plys containing either fiber cloth or cords for reinforcement.

Both sides of the drive belt may be used to drive the different accessory drive components. When the back side of the drive belt is used to drive a pulley, the pulley is smooth.

The drive belt is pulled by the crankshaft balancer pulley across the accessory drive component pulleys. The spring loaded drive belt tensioner keeps constant tension on the drive belt to prevent the drive belt from slipping. The drive belt tensioner arm will move when loads are applied to the drive belt by the accessory drive components and the crankshaft. The drive belt system may have an idler pulley, which is used to add wrap to the adjacent pulleys. Some systems use an idler pulley in place of an accessory drive component when the vehicle is not equipped with the accessory.

Scheme 52

The 5.3 Liter V8 engine is identified as RPO LM4 VIN P (5.3).