Hummer H3. Manual — part 87

7: Misalignment of the pulleys may be caused from improper mounting of the accessory
drive component, incorrect installation of the accessory drive component pulley, or the
pulley bent inward or outward from a previous repair. Test for a misalign pulley using a
straight edge in the pulley grooves across two or three pulleys. If a misalign pulley is found
refer to that accessory drive component for the proper installation procedure for that pulley.

8: This test is to verify that the pulleys are the correct diameter or width. Using a known
good vehicle compare the pulley sizes.

Drive Belt Squeal Diagnosis

Step

Action

Yes

No

DEFINITION: The following items are indications of drive belt squeal:

A loud screeching noise that is caused by a slipping drive belt (this is unusual for a
drive belt with multiple ribs)

The noise occurs when a heavy load is applied to the drive belt, such as an air
conditioning compressor engagement snapping the throttle, or slipping on a seized
pulley or a faulty accessory drive component.

NOTE:

Refer to Belt Dressing Notice in Cautions and Notices.

1

Did you review the Drive Belt Symptom
operation and perform the necessary inspections?

Go to Step 2

Go to
Symptoms -
Engine
Mechanical

2

Verify that there is a squeal noise.
Does the engine make the squeal noise?

Go to Step 3

Go to Diagnostic

Aids

3

1. Remove the drive belt(s). Refer to Drive

Belt Replacement (Without A/C) or
Drive Belt Replacement (With A/C).

2. Operate the engine for no longer than 30 to

40 seconds.

Does the noise still exist?

Go to Engine
Noise on Start-
Up, but Only
Lasting a Few
Seconds

Go to Step 4

4

Inspect for an accessory drive component seized
bearing or a faulty accessory drive component.
Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Test the drive belt tensioner for proper operation.
Refer to Drive Belt Tensioner Diagnosis.

2006 Hummer H3

2006 ENGINE Engine Mechanical - 3.5L (L52) - H3

DRIVE BELT WHINE DIAGNOSIS

Diagnostic Aids

The drive belt(s) will not cause the whine noise.

If the whine noise is intermittent, verify the accessory drive components by varying their loads
making sure they are operated to their maximum capacity. Such items but not limited to may be
an A/C system overcharged, the power steering system restricted or the wrong fluid, or the
generator failing.

Test Description

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

3: This test is to verify that the noise is being caused by the drive belt(s) or the accessory
drive components. When removing the drive belt the water pump may not be operating and
the engine may overheat. Also DTCs may set when the engine is operating with the drive
belt removed.

4: The 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 inspection and replacement procedure.

Drive Belt Whine Diagnosis

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Inspect for the correct drive belt length. Refer to
Drive Belt Replacement (Without A/C) or
Drive Belt Replacement (With A/C).
Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Inspect for misalignment of a pulley.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Inspect for the correct pulley size.
Did you find and correct the condition?

Go to Step 9

Go to Drive
Belt Idler
Pulley
Replacement

9

Operate the system in order to verify the repair.
Did you correct the condition?

System OK

Go to Step 3

2006 Hummer H3

2006 ENGINE Engine Mechanical - 3.5L (L52) - H3

DRIVE BELT RUMBLING DIAGNOSIS

Diagnostic Aids

Vibration from the engine operating may cause a body component or another part of the vehicle
to make rumbling noise.

The drive belt(s) may have a condition that can not be seen or felt. Sometimes replacing the drive
belt may be the only repair for the symptom.

If replacing the drive belt(s), completing the diagnostic table, and the noise is only heard when
the drive belt(s) is installed, there might be an accessory drive component with a failure. Varying
the load on the different accessory drive components may aid in identifying which component is
causing the rumbling noise.

Step

Action

Yes

No

DEFINITION: A high pitched continuous noise that may be caused by an accessory drive
component failed bearing.

NOTE:

Refer to Belt Dressing Notice in Cautions and Notices.

1

Did you review the Drive Belt Symptom
operation and perform the necessary inspections?

Go to Step 2

Go to

Symptoms -

Engine

Mechanical

2

Verify that there is a whine noise.
Does the engine make the whine noise?

Go to Step 3

Go to

Diagnostic Aids

3

1. Remove the drive belt(s). Refer to Drive

Belt Replacement (Without A/C) or
Drive Belt Replacement (With A/C).

2. Operate the engine for no longer than 30 to

40 seconds.

Does the whine noise still exist?

Go to Engine

Noise on Start-

Up, but Only

Lasting a Few

Seconds

Go to Step 4

4

Inspect for a failed accessory drive component
bearing.
Did you find and repair the condition?

Go to Step 5

Go to

Diagnostic Aids

5

Operate the system in order to verify the repair.
Did you correct the condition?

System OK

-

2006 Hummer H3

2006 ENGINE Engine Mechanical - 3.5L (L52) - H3

Test Description

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

2: This test is to verify that the symptom is present during diagnosing. Other vehicle
components may cause a similar symptom.

3: This test is to verify that the drive belt(s) is causing the rumbling noise. Rumbling noise
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. When removing
the drive belt the water pump may not be operating and the engine may overheat. Also
DTCs may set when the engine is operating with the drive belt removed.

4: Inspecting the drive belt(s) is to ensure that it is not causing a the noise. Small cracks
across the ribs of the drive belt will not cause the noise. Belt separation is identified by the
plys of the belt separating and may be seen at the edge of the belt our felt as a lump in the
belt.

5: Small amounts of pilling is normal condition and acceptable. When the pilling is severe
the drive belt does not have a smooth surface for proper operation.

Drive Belt Rumbling Diagnosis

Step

Action

Yes

No

DEFINITION:

A low pitch tapping, knocking, or thumping noise heard at or just above idle.

Heard once per revolution of the drive belt or a pulley.

Rumbling may be caused from:

Pilling, the accumulation of rubber dust that forms small balls (pills) or strings in
the drive belt pulley groove

The separation of the drive belt

A damaged drive belt

NOTE:

Refer to Belt Dressing Notice in Cautions and Notices.

1

Did you review the Drive Belt Symptom
operation and perform the necessary inspections?

Go to Step 2

Go to

Symptoms -

Engine

Mechanical

2

Verify that there is a rumbling noise.
Does the engine make the rumbling noise?

Go to Step 3

Go to

Diagnostic Aids

2006 Hummer H3

2006 ENGINE Engine Mechanical - 3.5L (L52) - H3