Chevrolet Silverado / GMC Sierra. Manual - part 404
ENGINE NOISE UNDER LOAD
connecting rods, crankshaft and
crankshaft journals.
2. Repair or replace all damaged
components.
Excessive crankshaft bearing clearance
1. Inspect the crankshaft bearings and
crankshaft journals.
2. Repair or replace all damaged
components.
Oil pump pickup tube or screen bent or loose
1. Inspect the oil pump pickup tube and/or
screen.
2. Repair or repalce all damaged
components.
Cause
Correction
Low oil pressure
Insufficient or poor oil supply to components.
1. Perform oil pressure test.
2. Repair or replace all damaged
components.
Loose torque converter bolts
1. Inspect the torque converter bolts and
flywheel.
2. Repair or replace all damaged
components.
Loose and/or damaged flywheel
1. Inspect the flywheel and flywheel
attaching bolts.
2. Repair or replace all damaged
components.
Excessive piston-to-cylinder bore clearance
1. Inspect the piston rings for low ring
tension, broken or worn rings, inspect
cylinder bore.
2. Repair or replace all damaged
components.
Excessive crankshaft thrust bearing clearance
1. Inspect the crankshaft end play and
crankshaft thrust bearings.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
ENGINE WILL NOT CRANK - CRANKSHAFT WILL NOT ROTATE
2. Repair or replace all damaged
components.
Excessive crankshaft bearing clearance
1. Inspect the crankshaft bearings and
crankshaft journals.
2. Repair or replace all damaged
components.
Cause
Correction
Seized accessory drive system component
1. Remove accessory drive belt(s).
2. Remove the glow plugs.
3. Rotate crankshaft by hand at the
balancer.
Hydraulically locked cylinder
Coolant/antifreeze in cylinder
Oil in cylinder
Fuel in cylinder
1. Inspect for fluid at glow plug hole.
2. Inspect for broken head gasket(s).
3. Inspect for cracked engine block or
cylinder head.
4. Inspect for a sticking fuel injector.
Seized automatic transmission torque
converter
1. Remove the engine assembly. The
torque converter bolts are not
accessible with the engine installed to
the transmission.
2. Rotate crankshaft by hand at the
balancer or flywheel location.
Seized manual transmission
1. Disengage the clutch.
2. Rotate crankshaft by hand at the
balancer.
Material in cylinder:
Broken valve
Piston material
Foreign material
1. Inspect cylinder for damaged
components and/or foreign materials.
2. Repair or replace as required.
Seized crankshaft or connecting rod bearings
1. Inspect crankshaft and connecting rod
bearings.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
COOLANT IN COMBUSTION CHAMBER
COOLANT IN ENGINE OIL
2. Repair as required.
Bent or broken connecting rod
1. Inspect connecting rods.
2. Repair as required.
Broken crankshaft
1. Inspect crankshaft.
2. Repair as required.
Inspection
Action
DEFINITION: Excessive white smoke and/or coolant type odor coming from the exhaust
pipe may indicate coolant in the combustion chamber. Low coolant levels, an inoperative
cooling fan, or a faulty thermostat may lead to an "overtemperature" condition which may
cause engine component damage.
Preliminary Inspection
Verify that there are no external coolant
leaks. Refer to Loss of Coolant .
Isolate Affected Cylinders
Cylinder balance test with scan tool
Cooling system pressurization
Inspection of glow plugs
Compression test
Cylinder leakdown test
EGR System Inspection
1. Inspect EGR valve and intake system for
evidence of coolant leakage.
2. Replace the EGR cooler if any problem
is found.
Cylinder Head Gasket Leakage
Remove cylinder heads of the affected
cylinder bank and inspect for damage.
Replace components as necessary.
Cylinder Head or Engine Block Damage
1. Inspect the cylinder heads for cracks and
warpage.
2. Inspect the cylinder block for damage.
3. Inspect the cylinder block to head
mating surface for straightness.
4. Replace components as necessary.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
FUEL IN ENGINE OIL
Definition: If fuel is suspected of leaking into the crankcase, the following procedure should be
performed to verify the condition.
1. Remove the oil level indicator and allow oil to drop onto a clean white paper towel.
2. If the oil is diluted with fuel, it will become apparent as the towel wicks the fuel away from
Cause
Correction
DEFINITION: Foamy or discolored oil or an engine oil "overfill" condition may indicate
coolant entering the engine crankcase. Low coolant levels, an inoperative cooling fan, or a
faulty thermostat may lead to an "overtemperature" condition which may cause engine
component damage. Contaminated engine oil and oil filter should be changed.
1. Inspect the oil for excessive foaming or an overfill condition. Oil diluted by coolant
may not properly lubricate the crankshaft bearings and may lead to component
damage. Refer to Lower Engine Noise, Regardless of Engine Speed.
2. Inspect by performing a Cylinder Leak-Down Test. During this test, excessive air
bubbles within the cooling system may indicate a faulty gasket or damaged
component.
3. Inspect by performing a cylinder compression test. Two cylinders "side-by-side" on
the engine block with low compression may indicate a failed cylinder head gasket.
Refer to Engine Compression Test.
Faulty cylinder head gasket
Replace the head gasket and components as
required. Refer to Cylinder Head Cleaning
and Inspection and Cylinder Head
Replacement - Left Side or Cylinder Head
Replacement - Right Side .
Warped cylinder head
Replace the cylinder head gasket. Refer to
Cylinder Head Replacement - Left Side or
Cylinder Head Replacement - Right Side .
Cracked cylinder head
Replace the cylinder head and gasket.
Cracked engine block
Replace the components as required.
Cylinder head, block, or manifold porosity
Replace the components as required.
Leaking engine oil cooler
Replace components as required.
Faulty water pump
Replace components as required.
Leaking cylinder head cup plug (under
rocker cover)
Replace components as required.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado