Chevrolet Silverado / GMC Sierra. Service manual — part 1855

EXHAUST SYSTEM DESCRIPTION

The exhaust system carries exhaust gases, treated by the catalytic converter, through the muffler
and into a resonator, if applicable where exhaust noise is lessened.

In order to secure the exhaust muffler assembly to the exhaust manifold, a flange and seal-joint
coupling is utilized. The exhaust system may utilize a slip-joint coupling design with a clamp and
a U-bolt or a flange connection with a gasket.

Exhaust hangers and rubber insulators help to support the weight of the exhaust system along with
insulating any exhaust system vibration, rattle, or noise.

Exhaust hangers also space the exhaust system away from the underbody of the vehicle and allows
the exhaust system to expand as the exhaust system warms up.

Exhaust heat shields are used to protect the underbody and other components from damage due to
the heat from the exhaust system.

The exhaust system may be comprised of the following components:

Catalytic converter

Exhaust hanger

Exhaust heat shield

Exhaust insulator

Exhaust manifold

Exhaust muffler

Exhaust pipe

Exhaust resonator, if equipped

Exhaust tail pipe, if equipped

Catalytic Converter

The catalytic converter is an emission control device added to the engine exhaust system in order
to reduce hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) pollutants
from the exhaust gas.

The catalytic converter is comprised of a ceramic monolith substrate, supported in insulation and

IMPORTANT: Use of non-OEM parts may cause driveability concerns.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

housed within a sheet metal shell. The substrate may be washcoated with 3 noble metals:

Palladium (Pd)

Platinum (Pt)

Rhodium (Rh)

The catalyst in the converter is not serviceable.

Muffler

The exhaust muffler reduces the noise levels of the engine exhaust by the use of tuning tubes. The
tuning tubes create channels inside the exhaust muffler that lower the sound levels created by the
combustion of the engine.

Resonator

Some exhaust systems may be equipped with a resonator. The resonator, located either before or
after the muffler, allows the use of mufflers with less back pressure. Resonators are used when
vehicle characteristics require specific exhaust tuning.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

Illustration

Tool Number/ Description

J 35314-A/BT-8515/BT-8515A

Exhaust Back Pressure Tester

J 38185

Hose Clamp Pliers

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

2008 ENGINE

Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

SPECIFICATIONS

FASTENER TIGHTENING SPECIFICATIONS

Application

Specification

Metric

English

Accessory Drive Belt Idler Pulley Bolt

50 N.m

37 lb ft

Accessory Drive Belt Tensioner Bolts

50 N.m

37 lb ft

Active Fuel Management Oil Pressure Relief Valve

27 N.m

20 lb ft

Air Conditioning Drive Belt Tensioner Bolts

50 N.m

37 lb ft

Automatic Transmission Flex Plate Bolts - First Pass

20 N.m

15 lb ft

Automatic Transmission Flex Plate Bolts - Second
Pass

50 N.m

37 lb ft

Automatic Transmission Flex Plate Bolts - Final
Pass

100 N.m

74 lb ft

Battery Cable Channel Bolt

12 N.m

106 lb in

Camshaft Position (CMP) Actuator Magnet Bolts

12 N.m

106 lb in

Camshaft Position (CMP) Actuator Solenoid Valve
- First Pass

65 N.m

48 lb ft

Camshaft Position (CMP) Actuator Solenoid Valve
- Final Pass

90 degrees

Camshaft Position (CMP) Sensor Bolt

12 N.m

106 lb in

Camshaft Position (CMP) Sensor Wire Harness Bolt

12 N.m

106 lb ft

Camshaft Retainer Bolts - Hex Head Bolts

25 N.m

18 lb ft

Camshaft Retainer Bolts - TORX Head Bolts

15 N.m

11 lb ft

Camshaft Sprocket Bolt - First Pass

75 N.m

55 lb ft

Camshaft Sprocket Bolt - Final Pass

50 degrees

Connecting Rod Bolts - First Pass

20 N.m

15 lb ft

Connecting Rod Bolts - Final Pass

85 degrees

Coolant Air Bleed Pipe and Cover Bolts

12 N.m

106 lb in

Coolant Temperature Sensor

20 N.m

15 lb ft

Crankshaft Balancer Bolt - Installation Pass - to

330 N.m

240 lb ft

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado