Hummer H3. Manual — part 81

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

Engine Noise on Start-Up, but Only Lasting a Few Seconds

UPPER ENGINE NOISE, REGARDLESS OF ENGINE SPEED

Upper Engine Noise, Regardless of Engine Speed

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

Inspect the spark plugs for oil deposits.

Repair or replace as required.

Worn Piston Rings
Oil consumption may or may not cause the
engine to misfire.

Inspect the spark plugs for oil deposits.

Inspect the cylinders for a loss of
compression. Refer to Engine
Compression Test.

Perform cylinder leak down and
compression testing to determine the
cause.

Repair or replace as required.

Cause

Correction

Incorrect oil filter without anti-drainback
feature

Install the correct oil filter.

Incorrect oil viscosity

1. Drain the oil.

2. Install the correct viscosity oil.

Worn crankshaft thrust bearing

Inspect the thrust bearing and
crankshaft.

Repair or replace as required.

Damaged or faulty oil filter by-pass valve

Inspect the oil filter by-pass valve for
proper operation.

Repair or replace as required.

Cause

Correction

Low oil pressure

Perform an oil pressure test. Refer to
Oil Pressure Diagnosis and Testing.

Repair or replace as required.

Worn or damaged valve rocker arm

Inspect the rocker arm for wear or
missing needle bearings

2006 Hummer H3

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

LOWER ENGINE NOISE, REGARDLESS OF ENGINE SPEED

Lower Engine Noise, Regardless of Engine Speed

Replace the valve rocker arms as
required.

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

or replace as required:

The valve rocker arm

The valve lash adjusters

The oil filter bypass valve

The oil transfer tube

The oil pump and pump screen

The engine block oil galleries

Broken valve spring

Replace the valve spring.

Worn or dirty valve lash adjusters

Replace the valve lash adjusters.

Stretched or broken timing chain and/or
damaged sprocket teeth

Replace the timing chain and sprockets.

Worn engine camshaft lobes

Inspect the engine camshaft lobes.

Replace the camshaft, valve lash
adjusters, and rocker arms as required.

Worn valve guides or valve stems

Inspect the following components, and repair
as required:

The valves

The valve guides

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

Inspect the following components, and repair
as required:

The valves

The valve guides

Cause

Correction

Low oil pressure

Perform an oil pressure test. Refer to
Oil Pressure Diagnosis and Testing.

Repair or replace damaged components

2006 Hummer H3

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

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.

Inspect the accessory drive system.

Repair or replace as required.

Loose or damaged crankshaft balancer

Inspect the crankshaft balancer.

Repair or replace as required.

Detonation or spark knock

Verify the correct operation of the ignition
system. Refer to Detonation/Spark Knock
in Engine Controls.

Loose torque converter bolts

Inspect the torque converter bolts and
flywheel.

Repair or replace as required.

Loose or damaged flywheel

Repair or replace the flywheel.

Oil pump screen loose, damaged or restricted

Inspect the oil pump screen.

Repair or replace as required.

Oil transfer tube loose, damaged or restricted

Inspect the transfer tube.

Repair or replace as required.

Excessive piston-to-cylinder bore clearance

Inspect the piston and cylinder bore.

Repair as required.

Excessive piston pin-to-bore clearance

Inspect the piston, piston pin, and the
connecting rod.

Repair or replace as required.

Excessive connecting rod bearing clearance

Inspect the following components, and repair
as required:

The connecting rod bearings

The connecting rods

The crankshaft

The crankshaft journals

Excessive crankshaft bearing clearance

Inspect the following components, and repair
as required:

The crankshaft bearings

2006 Hummer H3

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

ENGINE NOISE UNDER LOAD

Engine Noise Under Load

The crankshaft journals

Incorrect piston, piston pin and connecting
rod installation
Pistons must be installed with the arrow or
paint on the top of the piston facing the front
of the engine. From the bottom, the squared
pin boss must be toward the front of the
engine.

Verify the pistons, piston pins and
connecting rods are installed correctly.

Repair as required.

Cause

Correction

Low oil pressure

Perform an oil pressure test. Refer to
Oil Pressure Diagnosis and Testing.

Repair or replace as required.

Detonation or spark knock

Verify the correct operation of the ignition
system. Refer to Detonation/Spark Knock
in Engine Controls.

Loose torque converter bolts

Inspect the torque converter bolts and
flywheel.

Repair as required.

Cracked flywheel (automatic transmission)

Inspect the flywheel bolts and flywheel.

Repair as required.

Excessive connecting rod bearing clearance

Inspect the following components, and repair
as required:

The connecting rod bearings

The connecting rods

The crankshaft

Excessive crankshaft bearing clearance

Inspect the following components, and repair
as required:

The crankshaft bearings

The crankshaft journals

The cylinder block crankshaft bearing

2006 Hummer H3

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