Hummer H2. Manual — part 1886

Fig. 692: Balancer Proper Installation Position
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: The nose of the crankshaft should be recessed 2.4-4.48 mm (0.094-0.176

in) into the balancer bore.

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

6. Measure for a correctly installed balancer.

If the balancer is not installed to the proper dimensions, install the J 41665 and repeat the installation
procedure. See Special Tools and Equipment .

Fig. 693: View Of Crankshaft Balancer
Courtesy of GENERAL MOTORS CORP.

7. Install the NEW crankshaft balancer bolt.

Tighten:

1. Tighten the crankshaft balancer bolt a first pass to 50 N.m (37 lb ft).

2. Tighten the crankshaft balancer bolt a second pass to 140 degrees using the J 45059 . See Special

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

Tools and Equipment .

8. Remove the J 42386-A .

DESCRIPTION AND OPERATION

CRANKCASE VENTILATION SYSTEM DESCRIPTION

A closed crankcase ventilation system is used in order to provide a more complete scavenging of the 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 valve into the intake manifold.

The primary control is through the crankcase ventilation valve which meters the flow at a rate depending on
manifold vacuum. To maintain idle quality, the crankcase ventilation valve restricts the flow when intake
manifold vacuum is high. If abnormal operating conditions arise, the system is designed to allow excessive
amounts of blow-by gases to back flow through the crankcase vent tube into the engine air inlet to be consumed
by normal combustion.

Filtered fresh air is routed from up-stream of the throttle blade to the front of the right rocker arm cover via a
formed rubber hose. To reduce the potential of oil pullover into the throttle bore area due to back flow of the
ventilation system, the fitting in the right rocker arm cover is shielded from the rocker arms. From there fresh
air and gases are routed through the crankcase and up to the opposite rocker arm cover where the positive
crankcase ventilation (PCV) valve is located. Gases are then routed through a hose to the intake manifold.

DRIVE BELT SYSTEM DESCRIPTION

or

The drive belt system consists of the following components:

z

The drive belt

z

The drive belt tensioner

z

The drive belt idler pulley

z

The crankshaft balancer pulley

z

The accessory drive component mounting brackets

z

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

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

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.

ENGINE COMPONENT DESCRIPTION

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2