Chevrolet Silverado / GMC Sierra. Service manual — part 8

BASE ENGINE MISFIRE WITH ABNORMAL INTERNAL LOWER ENGINE NOISES

sprockets

Repair or replace damaged components
as required.

Worn, damaged or improperly installed
piston
Pistons must be installed with the mark, or
dimple, on the top of the piston, facing the
front of the engine; piston pins must be
centered in the connecting rod pin bore.
Oil consumption may or may not cause the
engine to misfire.

Inspect the spark plugs. Refer to Spark
Plug Inspection .

Verify engine compression. Refer to
Engine Compression Test.

Inspect the cylinder bores.

Inspect the pistons.

Inspect the piston pins.

Inspect the connecting rods.

Repair or replace damaged components
as required.

Cause

Correction

Worn, damaged, or improperly installed
accessory drive belt - severe cracking, bumps
or missing segments
A misfire DTC may be present without an
actual misfire condition.

Inspect the accessory drive system
components.

Repair or replace damaged components
as required. Refer to Drive Belt
Replacement.

Worn, damaged, or improperly installed
accessory drive system components
A misfire DTC may be present without an
actual misfire condition.

Inspect the accessory drive system
components.

Repair or replace damaged components
as required.

Worn, damaged, improperly installed or
loose crankshaft balancer
A misfire code may be present without an
actual misfire condition.

Inspect the crankshaft balancer.

Repair or replace damaged components
as required. Refer to Crankshaft
Balancer Replacement.

Worn, damaged, improperly installed or
loose engine flywheel
A misfire code may be present without an
actual misfire condition.

Inspect the engine flywheel.

Repair or replace damaged components
as required. Refer to Engine Flywheel
Replacement.

Worn, damaged or improperly installed
piston

Inspect the spark plugs. Refer to Spark
Plug Inspection .

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

BASE ENGINE MISFIRE WITH ABNORMAL VALVE TRAIN NOISE

Pistons must be installed with the mark, or
dimple, on the top of the piston, facing the
front of the engine; piston pins must be
centered in the connecting rod pin bore.
Oil consumption may or may not cause the
engine to misfire.

Verify engine compression. Refer to
Engine Compression Test.

Inspect the cylinder bores.

Inspect the pistons.

Inspect the piston pins.

Inspect the connecting rods.

Repair or replace damaged components
as required.

Worn, damaged or improperly installed
crankshaft thrust bearing
A misfire code may be present without an
actual misfire condition.

Inspect the crankshaft.

Inspect the crankshaft thrust bearing.

Repair or replace damaged components
as required.

Cause

Correction

Worn, damaged or loose rocker arm

Inspect the valve rocker arms.

Repair or replace damaged components
as required.

Worn, damaged, loose or bent valve push rod

Inspect the valve push rods.

Repair or replace damaged components
as required.

Worn, damaged or stuck valve, carbon on the
valve stem or valve seat

Inspect the valves.

Inspect the valve guides.

Repair or replace damaged components
as required.

Worn, damaged or dirty valve lifter

Inspect the valve lifters.

Inspect the camshaft.

Repair or replace damaged components
as required.

Worn or damaged camshaft lobe

Inspect the camshaft.

Inspect the valve lifters.

Repair or replace damaged components
as required.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

BASE ENGINE MISFIRE WITH COOLANT CONSUMPTION

BASE ENGINE MISFIRE WITH EXCESSIVE OIL CONSUMPTION

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

Worn, damaged or loose timing chain and
sprockets

Inspect the timing chain and sprockets.

Repair or replace damaged components
as required.

Cause

Correction

Damaged or improperly installed cylinder
head
Coolant consumption may or may not cause
the engine to misfire.

Inspect the spark plugs. Refer to Spark
Plug Inspection .

Verify engine compression. Refer to
Engine Compression Test.

Inspect the cylinder heads.

Inspect the engine block.

Repair or replace damaged components
as required.

Cause

Correction

Worn or damaged valve

Inspect the valves.

Inspect the valve guides.

Repair or replace damaged components
as required.

Worn, damaged or improperly installed
piston rings
Piston rings must be installed with the mark,
or dimple, on the top of the piston ring,
facing up.

Inspect the spark plugs. Refer to Spark
Plug Inspection .

Verify engine compression. Refer to
Engine Compression Test.

Inspect the cylinder bores.

Inspect the pistons.

Inspect the piston pins.

Inspect the connecting rods.

Repair or replace damaged components
as required.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

UPPER ENGINE NOISE, REGARDLESS OF ENGINE SPEED

Cause

Correction

Incorrect engine oil, viscosity

Install the correct engine oil and oil filter.
Refer to Engine Oil and Oil Filter
Replacement.

Incorrect oil filter, without anti-drainback
feature

Install the correct engine oil and oil filter.
Refer to Engine Oil and Oil Filter
Replacement.

Worn, damaged, or improperly installed oil
filter by-pass valve

1. Inspect the oil filter by-pass valve.

2. Repair or replace damaged components

as required.

High valve lifter leak down rate

1. Inspect the valve lifters.

2. Repair or replace damaged components

as required.

Worn, damaged, or improperly installed
crankshaft thrust bearing

1. Inspect the crankshaft.

2. Inspect the crankshaft thrust bearing.

3. Repair or replace damaged components

as required.

Cause

Correction

Low oil pressure

Verify oil pressure. Refer to Oil
Pressure Diagnosis and Testing.

Repair or replace damaged components
as required.

Improper lubrication of the valve train
components

Verify oil pressure. Refer to Oil
Pressure Diagnosis and Testing.

Inspect the valve rocker arms.

Inspect the valve push rods.

Inspect the valve lifters.

Inspect the oil filter bypass valve.

Inspect the oil pump and pump screen.

Inspect the engine block oil galleries.

Repair or replace damaged components
as required.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado