Chevrolet Silverado / GMC Sierra. Manual - part 403
BASE ENGINE MISFIRE WITH EXCESSIVE OIL CONSUMPTION
ENGINE NOISE ON START-UP, BUT ONLY LASTING A FEW SECONDS
Cylinder Head or Engine Block Damage
3. Inspect the cylinder block to head
mating surface for straightness.
4. Replace components as necessary.
Condition
Action
Worn valve guides
1. Inspect the valves and valve guides.
2. Repair or replace all damaged
components.
Worn valve stem oil seals
1. Inspect the valve stem oil seals.
2. Repair or replace all damaged
components.
Excessive piston-to-cylinder bore clearance
1. Perform cylinder leak down and
compression tests to determine the
cause.
2. Inspect the piston rings for low ring
tension, broken or worn rings.
3. Inspect cylinder bore.
4. Repair or replace all damaged
components.
Condition
Action
Incorrect oil viscosity
1. Drain the oil.
2. Install the correct viscosity oil.
Excessive piston-to-cylinder bore clearance
1. Inspect the piston and piston skirt,
connecting rod, and cylinder bore.
2. Repair or replace all damaged
components.
Damaged or faulty oil filter by-pass valve
1. Inspect the oil filter by-pass valve for
proper operation.
2. Repair or replace as necessary.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
UPPER ENGINE NOISE, REGARDLESS OF ENGINE SPEED
Condition
Action
Low oil pressure
Insufficient or poor oil supply to valve train.
1. Perform oil pressure test.
2. Repair or replace all damaged
components.
Improper lubrication to the valve rocker
arms
1. Inspect valve rocker arm and shaft,
valve pushrod, oil filter bypass valve, oil
pump and pump screen, and engine
block oil galleries.
2. Repair or replace all damaged
components.
Excessive valve lash
1. Check the valve lash adjustment, and
correct if above specifications.
2. Repair or replace all damaged
components.
Worn pushrod upper end ball
1. Inspect pushrod end ball.
2. Repair or replace all damaged
components.
Bent valve pushrod
1. Inspect valve pushrod and valve rocker
arm.
2. Repair or replace all damaged
components.
Loose, worn or damaged valve rocker arm
1. Inspect valve rocker arm and rocker arm
shaft.
2. Repair or replace all damaged
components.
Loose valve rocker arm attachments
1. Inspect valve rocker arm and rocker arm
shaft.
2. Repair or replace all damaged
components.
Broken valve springs
1. Inspect valve springs.
2. Repair or replace all damaged
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
LOWER ENGINE NOISE, REGARDLESS OF ENGINE SPEED
components.
Worn and/or damaged valve spring shims,
seats, or keys
1. Inspect valve spring shims, seats, and
keys.
2. Repair or replace all damaged
components.
Sticking valve
Carbon on the valve stem or valve seat may
cause the valve to stick.
1. Inspect valves and valve guides.
2. Repair or replace all damaged
components.
Missing or improperly positioned lifter
guides
1. Inspect lifter guides.
2. Repair or replace all damaged
components.
Worn or faulty camshaft lobes
1. Inspect camshaft lobes.
2. If damaged replace camshaft and all
lifters.
Worn valve guide
1. Inspect the valves and valve guides.
2. Repair or replace all damaged
components.
Damaged or misaligned timing gears
1. Inspect timing gears.
2. Replace all damaged components.
Condition
Action
Worn accessory drive components
(abnormalities such as severe cracking,
bumps or missing areas in the accessory drive
belt and/or misalignment of the system
components.)
1. Inspect the accessory drive components.
2. Repair or replace all damaged
components.
Low oil pressure
Insufficient or poor oil supply to crankshaft
and connecting rod bearings.
1. Perform oil pressure test.
2. Repair or replace all damaged
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
components.
Leaking and/or sticking fuel injection nozzle
(A stuck fuel injection nozzle can cause a
noise similar to a damaged piston, rod or rod
bearing.)
1. Use the cylinder balance diagnostic
procedure to help locate the cylinder
that is the source of the noise.
2. If you cannot locate the cylinder that is
the source of the noise, diagnose the
engine for mechanical damage.
3. If it has been determined that the fuel
injection nozzle is causing the noise,
replace the fuel injection nozzle.
Loose and/or damaged crankshaft balancer
1. Inspect crankshaft balancer and
balancer bolt.
2. Repair or replace all damaged
components.
Loose torque converter bolts
1. Inspect torque converter bolts and
flywheel.
2. Repair or replace all damaged
components.
Loose and/or damaged flywheel
1. Inspect flywheel and flyweel attaching
bolts.
2. Repair or replace all damaged
components.
Excessive piston-to-cylinder bore clearance
1. Inspect the piston, piston rings and
cylinder bore.
2. Repair or replace all damaged
components.
Excessive piston pin-to-bore clearance
1. Inspect the piston, piston pin, and the
connecting rod.
2. Repair or replace all damaged
components.
Misaligned or bent connecting rod
1. Inspect connecting rod and connecting
rod bearings.
2. Repair or replace all damaged
components.
Excessive connecting rod bearing clearance
1. Inspect the connecting rod bearings,
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado