Chevrolet Silverado / GMC Sierra. Service manual — part 1877

BASE ENGINE MISFIRE WITH COOLANT CONSUMPTION

BASE ENGINE MISFIRE WITH EXCESSIVE OIL CONSUMPTION

ENGINE NOISE ON START-UP, BUT ONLY LASTING A FEW SECONDS

Cause

Correction

Faulty cylinder head gaskets and/or cracking
or other damage to the cylinder heads and
engine block cooling system passages
Coolant consumption may or may not cause
the engine to overheat.

1. Inspect for spark plugs saturated by

coolant. Refer to Spark Plug
Inspection .

2. Perform a cylinder leak down test.

Refer to Cylinder Leakage Test.

3. Inspect the cylinder heads and engine

block for damage to the coolant
passages and/or a faulty head gasket.
Refer to Coolant in Combustion
Chamber.

4. Repair or replace, as required.

Cause

Correction

Worn valves, valve guides and/or valve stem
oil seals

1. Inspect the spark plugs for oil deposits.

Refer to Spark Plug Inspection .

2. Repair or replace, as required.

Worn piston rings
Oil consumption may or may not cause the
engine to misfire.

1. Inspect the spark plugs for oil deposits.

Refer to Spark Plug Inspection .

2. Inspect the cylinders for a loss of

compression. Refer to Engine
Compression Test.

3. Perform cylinder leak down and

compression testing to determine the
cause. Refer to Cylinder Leakage
Test.

4. Repair or replace, as required.

Cause

Correction

Incorrect oil filter without anti-drainback
feature

Install the correct oil filter.

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

UPPER ENGINE NOISE, REGARDLESS OF ENGINE SPEED

Incorrect oil viscosity

1. Drain the oil.

2. Install the correct viscosity oil.

High valve lifter leak down rate

Replace the lifters, as required.

Worn crankshaft thrust bearing

1. Inspect the crankshaft end play.

2. Inspect the thrust bearing and

crankshaft.

3. Repair or replace, as required.

Damaged or faulty oil filter bypass valve
The bypass valve is now internal to the oil
filter.

1. Inspect the oil filter bypass valve for

proper operation.

2. Repair or replace, as required.

Cause

Correction

Low oil pressure

1. Perform an oil pressure test. Refer to

Oil Pressure Diagnosis and Testing.

2. Repair or replace, as required.

Loose and/or worn valve rocker arm
attachments

1. Inspect the valve rocker arm, bolt, and

pedestal.

2. Repair or replace, as required.

Worn or damaged valve rocker arm

1. Inspect the rocker arm for wear or

missing needle bearings

2. Replace the valve rocker arms, as

required.

Bent or damaged push rod

Inspect the following components and
replace, as required:

The valve rocker arm

The valve push rod

The valve lifter

The valve lifter guide

The piston

Inspect the top of the pistons for valve

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

contact. If the top of the piston shows valve
contact, replace the piston and pin assembly.

Improper lubrication to the valve rocker arms Inspect the following components and repair

or replace, as required:

The valve rocker arm

The valve push rod

The valve lifter

The oil filter bypass valve

The oil pump and pump screen

Improper operation of the active fuel
management oil pressure relief valve

The engine block oil galleries

Broken valve spring

Replace the valve spring and spring shim.

Worn or dirty valve lifters

Replace the valve lifters, as required.

Active fuel management valve lifter with a
broken spring

Replace the valve lifters, as required.

Improper operation of the active fuel
management oil pressure relief valve

Repair, as required. Refer to Cylinder
Deactivation (Active Fuel Management)
Oil Pressure Relief Valve Diagnosis and
Testing.

Improper operation of the camshaft position
(CMP) actuator and/or control system

Repair, as required. Refer to Camshaft
Position Actuator and Solenoid Valve
Diagnosis and Testing.

Stretched or broken timing chain and/or
damaged sprocket teeth

Replace the timing chain and sprockets.

Worn engine camshaft lobes

1. Inspect the engine camshaft lobes.

2. Replace the camshaft and valve lifters,

as required.

Worn valve guides or valve stems

Inspect the following components and repair,
as required:

The valves

The valve guides

Stuck valves

Inspect the following components and repair,
as required:

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

LOWER ENGINE NOISE, REGARDLESS OF ENGINE SPEED

Carbon on the valve stem or valve seat may
cause the valve to stay open.

The valves

The valve guides

Cut or damaged oil pump screen O-ring seal
which may cause aeration of the engine oil

Repair, as required. Refer to Oil Pressure
Diagnosis and Testing.

Cause

Correction

Low oil pressure

1. Perform an oil pressure test. Refer to

Oil Pressure Diagnosis and Testing.

2. Repair or replace damaged components,

as required.

Worn accessory drive components
Abnormalities such as severe cracking, bumps
or missing areas in the accessory drive belt
and/or misalignment of system components.

1. Inspect the accessory drive system.

2. Repair or replace, as required.

Loose or damaged crankshaft balancer

1. Inspect the crankshaft balancer.

2. Repair or replace, as required.

Detonation or spark knock

Verify the correct operation of the ignition
controls system. Refer to Symptoms -
Engine Controls .

Loose torque converter bolts

1. Inspect the torque converter bolts and

flex plate.

2. Repair or replace, as required.

Loose or damaged flywheel or flex plate

Repair or replace the flywheel or flex plate.

Oil pump screen loose, damaged, or
restricted

1. Inspect the oil pump screen.

2. Repair or replace, as required.

Excessive piston-to-cylinder bore clearance

1. Inspect the piston and cylinder bore.

2. Repair, as required.

Excessive piston pin-to-bore clearance

1. Inspect the piston, pin, and connecting

rod.

2. Replace the piston and pin as an

assembly, as required.

Excessive connecting rod bearing clearance

Inspect the following components and repair,
as required:

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