Hummer H3. Instruction - page 86

Plugged vacuum orifice tube (5) in the camshaft cover

Plugged, restricted, or leaking PCV dirty air hose (2)

Plugged or restricted intake manifold passage (3)

Excessive crankcase pressure or blow-by, refer to Engine Compression Test

Additional items to inspect:

Plugged or restricted vacuum tube (4) in the camshaft cover

Plugged or restricted PCV fresh air hose (6)

Plugged or restricted passage in the air cleaner resonator (1)

Inspect the cam cover, the oil pan, engine front cover, and other sealing areas for leaks

Results of Incorrect Operation

A plugged crankcase ventilation system may contribute to the following conditions:

A rough idle

Stalling or a slow idle speed

Oil leaks

Oil accumulation in the air cleaner resonator (1)

Sludge in the engine

A leaking hose may contribute to the following conditions:

A rough idle

Stalling

Unstable idle speed

The crankcase ventilation system has no serviceable components so no maintenance of the system
is required.

DRIVE BELT CHIRPING DIAGNOSIS

Diagnostic Aids

The symptom may be intermittent due to moisture on the drive belt(s) or the pulleys. It may be
necessary to spray a small amount of water on the drive belt(s) in order to duplicate the customers
concern. If spraying water on the drive belt(s) duplicates the symptom, cleaning the belt pulleys
may be the probable solution.

2006 Hummer H3

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

A loose or improper installation of a body component, a suspension component, or other items of
the vehicle may cause the chirping noise.

Test Description

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

2: The 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 further with this table.

3: The noise may be an internal engine noise. Removing the drive belt and operating the
engine for a brief period will verify the noise is related to the drive belt. When removing the
drive belt(s) 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: Inspect all drive belt pulleys for pilling. Pilling is the small balls or pills or it may be
strings in the drive belt grooves from the accumulation of rubber dust.

6: 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.

10: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or
washer was installed.

12: Inspecting the pulleys for being bent should include inspecting for a dent or other
damage to the pulleys that would prevent the drive belt from not seating properly in all of
the pulley grooves or on the smooth surface of a pulley when the back side of the belt is
used to drive the pulley.

14: Replacing the drive belt when it is not damaged or there is not excessive pilling will
only be a temporary repair.

Drive Belt Chirping Diagnosis

Step

Action

Yes

No

DEFINITION: The following items are indications of chirping:

A high pitched noise that is heard once per revolution of the drive belt or a pulley.

It usually occurs on cold damp mornings and will subside once vehicle reached normal
operating temp.

NOTE:

Refer to Belt Dressing Notice in Cautions and Notices.

2006 Hummer H3

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

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 chirping noise.
Does the engine make the chirping noise?

Go to Step 3

Go to

Diagnostic Aids

3

1. Remove the drive belt. 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 chirping noise still exist?

Go to Engine

Noise on Start-

Up, but Only

Lasting a Few

Seconds

Go to Step 4

4

Inspect for severe pilling exceeding 1/3 of the belt
groove depth.
Does the belt grooves have pilling?

Go to Step 5

Go to Step 6

5

Clean the drive belt pulleys with a suitable wire
brush.
Did you complete the repair?

Go to Step 15

Go to Step 6

6

Inspect for misalignment of the pulleys.
Are any of the pulleys misaligned?

Go to Step 7

Go to Step 8

7

Replace or repair any misaligned pulleys.
Did you complete the repair?

Go to Step 15

Go to Step 8

8

Inspect for bent or cracked brackets.
Did you find any bent or cracked brackets?

Go to Step 9

Go to Step 10

9

Replace any bent or cracked brackets.
Did you complete the repair?

Go to Step 15 Go to Step 10

10

Inspect for improper, loose or missing fasteners.
Did you find the condition?

Go to Step 11 Go to Step 12

11

Tighten any loose fasteners.
Replace any improper or missing fasteners. Refer
to Fastener Tightening Specifications.
Did you complete the repair?

Go to Step 15 Go to Step 12

12

Inspect for a bent pulley.
Did you find the condition?

Go to Step 13 Go to Step 14

13

Replace the bent pulley.
Did you complete the repair?

Go to Step 15 Go to Step 14

2006 Hummer H3

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

DRIVE BELT SQUEAL DIAGNOSIS

Diagnostic Aids

A loose or improper installation of a body component, a suspension component, or other items of
the vehicle may cause the squeal noise.

If the noise is intermittent, verify the accessory drive components by varying their loads making
sure they are operated to their maximum capacity. An overcharged A/C system, power steering
system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.

Test Description

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

2: The 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 further with this table

3: The noise may be an internal engine noise. Removing the drive belt and operating the
engine for a brief period will verify the squeal noise is the drive belts or an accessory drive
component. 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: This test is to verify that an accessory drive component does not have a seized bearing.
With the belt remove test the bearings in the accessory drive components for turning
smoothly. Also test the accessory drive components with the engine operating by varying the
load on the components to verify that the components operate properly.

5: This test is to verify that the drive belt tensioner operates properly. If the drive belt
tensioner is not operating properly, proper belt tension may not be achieved to keep the
drive belt from slipping which could cause a squeal noise.

6: This test is to verify that the drive belts is not too long, which would prevent the drive
belt tensioner from working properly. Also if an incorrect length drive belt was installed, it
may not be routed properly and may be turning an accessory drive component in the wrong
direction.

14

Replace the drive belt. Refer to Drive Belt
Replacement (Without A/C)
or Drive Belt
Replacement (With A/C)

Did you complete the repair?

Go to Step 15

Go to

Diagnostic Aids

15

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

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