Engine Mechanical - 3.5l - Diagnostic Information and Procedures

Strategy Based Diagnostics

Perform «Diagnostic System Check - Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables-if applicable.
Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-component-locator) , «Engine Component Description»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-description-and-operation__engine-component-description) , «Drive Belt System Description»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-description-and-operation__drive-belt-system-description) and «Lubrication Description»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-description-and-operation) .

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system problem. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis .

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the Engine. Refer to «Checking Aftermarket Accessories»(/chevrolet/malibu/vii-2008-2012/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Check for the correct oil level, proper oil viscosity, and correct filter application.
Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
Compare the engine sounds-if applicable to a known good engine and make sure you are not trying to correct a normal condition.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

«Base Engine Misfire without Internal Engine Noises»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__base-engine-misfire-without-internal-engine)
«Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-internal)
«Base Engine Misfire with Abnormal Valve Train Noise»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-valve)
«Base Engine Misfire with Coolant Consumption»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__base-engine-misfire-with-coolant-consumption)
«Base Engine Misfire with Excessive Oil Consumption»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__base-engine-misfire-with-excessive-oil)
«Engine Compression Test»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__engine-noise-on-start-up-but-only)
«Upper Engine Noise, Regardless of Engine Speed»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__upper-engine-noise-regardless-of-engine)
«Lower Engine Noise, Regardless of Engine Speed»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__lower-engine-noise-regardless-of-engine)
«Engine Noise Under Load»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__engine-noise-under-load)
«Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft)
«Oil Consumption Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__oil-consumption-diagnosis)
«Oil Pressure Diagnosis and Testing»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Oil Leak Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Drive Belt Chirping, Squeal, and Whine Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Drive Belt Rumbling and Vibration Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Drive Belt Falls Off and Excessive Wear Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures)
«Valve Rocker Arm Cover Replacement - Right Side»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-on-vehicle)
«Drive Belt Tensioner Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis)

Base Engine Misfire without Internal Engine Noises

Cause	Correction
Engine oil level overfull, causing aeration	Drain excess oil and adjust oil level to proper specification.
Abnormalities - severe cracking, bumps, or missing areas in the accessory drive belt Abnormalities in the accessory drive system and/or components may cause engine RPM variations and lead to a misfire DTC. A misfire code may be present without an actual misfire condition.	Replace the drive belt. Refer to Drive Belt Tensioner Replacement .
Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout may lead to a misfire DTC-A misfire code may be present without an actual misfire condition.	Inspect the components, and repair or replace as required.
Loose or improperly installed engine flywheel or crankshaft balancer-A misfire code may be present without an actual misfire condition.	Repair or replace the flywheel and/or balancer as required. Refer to Engine Flywheel Replacement or Crankshaft Balancer Replacement .
Restricted exhaust system-A severe restriction in the exhaust flow can cause significant loss of engine performance and may set a DTC. Possible causes of restrictions include collapsed or dented pipes or plugged mufflers and/or catalytic converters.	Repair or replace as required.
Improperly installed or damaged vacuum hoses	Repair or replace as required.
Improper sealing between the intake manifold and cylinder heads or throttle body.	Replace the intake manifold, gaskets, cylinder heads, and/or throttle body as required.
Worn or loose rocker arms-The rocker arm bearing end caps and/or needle bearings should be intact and in the proper position.	Replace the valve rocker arms as required.
Worn or bent pushrods	Replace the pushrods.
Stuck valves-Carbon buildup on the valve stem can cause the valve not to close properly.	Repair or replace as required.
Excessively worn or out of time timing chain	Replace the timing chain and sprockets as required.
Worn camshaft lobes	Replace the camshaft and valve lifters.
Excessive oil pressure-A lubrication system with excessive oil pressure may lead to excessive valve lifter pump-up and loss of compression.	Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing . Repair or replace the oil pump as required.
Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages-Refer to Diagnostic Starting Point - Engine Cooling. Coolant consumption may or may not cause the engine to overheat.	Inspect for spark plugs saturated by coolant. Refer to Spark Plug Inspection . Inspect the cylinder heads, engine block, and/or head gaskets. 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. Refer to Spark Plug Inspection . Inspect the cylinders for a loss of compression. Refer to Engine Compression Test . Perform cylinder leak down and compression testing to identify the cause. Repair or replace as required.

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Cause	Correction
Abnormalities-severe cracking, bumps or missing areas in the accessory drive belt Abnormalities in the accessory drive system and/or components may cause engine RPM variations, noises similar to a faulty lower engine and also lead to a misfire condition. A misfire code may be present without an actual misfire condition.	Replace the drive belt. Refer to Drive Belt Tensioner Replacement .
Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout-A misfire code may be present without an actual misfire condition.	Inspect the components, repair or replace as required.
Loose or improperly installed engine flywheel or crankshaft balancer-A misfire code may be present without an actual misfire condition.	Repair or replace the flywheel and/or balancer as required. Refer to Engine Flywheel Replacement or Crankshaft Balancer Replacement .
Worn piston rings-Oil consumption may or may not cause the engine to misfire.	Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection . 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.
Worn crankshaft thrust bearings- Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit fore and aft movement of the crankshaft and create a DTC without an actual misfire condition.	Replace the crankshaft and bearings as required.

Base Engine Misfire with Abnormal Valve Train Noise

Cause	Correction
Engine oil level overfull, causing aeration	Drain excess oil and adjust oil level to proper specification.
Worn or loose rocker arms-The rocker arm bearing end caps and/or needle bearings should intact within the rocker arm assembly.	Replace the valve rocker arms as required.
Worn or bent pushrods	Replace the pushrods.
Stuck valves-Carbon buildup on the valve stem can cause the valve not to close properly.	Repair or replace as required.
Excessively worn or mis-aligned timing chain	Replace the timing chain and sprockets as required.
Worn camshaft lobes	Replace the camshaft and valve lifters.
Sticking lifters	Replace as required.
Malfunctioning camshaft position actuator-Improper viscosity oil, contaminated oil, or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.	Verify correct oil viscosity by changing the engine oil and oil filter and re-evaluating the concern. Inspect for a missing or plugged camshaft position actuator filter. If filter is missing, replace the filter, replace the camshaft position actuator, and change the engine oil and oil filter. If filter is plugged, replace the filter, and change the engine oil and oil filter. If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.

Base Engine Misfire with Coolant Consumption

Cause	Correction
Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages-Refer to Diagnostic System Check - Vehicle . Coolant consumption may or may not cause the engine to overheat.	Inspect for spark plugs saturated by coolant. Refer to Spark Plug Inspection . Perform a cylinder leak down test. Inspect the cylinder heads and engine block for damage to the coolant passages and/or a faulty head gasket. Repair or replace as required.

Base Engine Misfire with Excessive Oil Consumption

Cause	Correction
Worn valves, valve guides and/or valve stem oil seals	Inspect the spark plugs for oil deposits. Refer to Spark Plug Inspection . 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. Refer to Spark Plug Inspection . 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.

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

Cause	Correction
IMPORTANT: The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.
Incorrect oil filter without anti-drainback feature	Install the correct oil filter.
Incorrect oil viscosity	Drain the oil. Install the correct viscosity oil.
Worn crankshaft thrust bearing	Inspect the thrust bearing and crankshaft. Repair or replace as required.
High valve lifter leak down rate	Replace the lifters as required.
Excessive crank/rod bearing clearances	Inspect the crankshaft and rod bearings. Repair or replace as required.

IMPORTANT
The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.

Upper Engine Noise, Regardless of Engine Speed

Cause	Correction
IMPORTANT: The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.
Engine oil level overfull, causing aeration	Drain excess oil and adjust oil level to proper specification.
Low oil pressure	Perform an oil pressure test. Refer Oil Pressure Diagnosis and Testing . Repair or replace as required.
Loose and/or worn valve rocker arm attachments	Inspect the valve rocker arm stud, nut, or bolt. Repair or replace as required.
Worn valve rocker arm	Replace the valve rocker arm.
Bent or damaged push rod	Inspect the following components, and replace as required: The valve rocker arm The valve push rod The valve lifter
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 The engine block oil galleries
Broken valve spring	Replace the valve spring.
Worn and/or damaged valve rotators	Replace the valve rotators as required.
Worn or dirty valve lifters	Replace the valve lifters.
Stretched or broken timing chain and/or damaged sprocket teeth	Replace the timing chain and sprockets.
Worn timing chain tensioner, if applicable	Replace the timing chain tensioners as required.
Worn engine camshaft lobes	Inspect the engine camshaft lobes. Replace the camshaft and valve lifters as required.
Damaged, broken, or dirty, balance shaft sprocket teeth, if applicable	Inspect the following components, and repair as required: The balance shaft gear The camshaft gear The balance shaft rear bushing
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
Malfunctioning camshaft position actuator-Improper viscosity oil, contaminated oil, or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.	Verify correct oil viscosity by changing the engine oil and oil filter and re-evaluating the concern. Inspect for a missing or plugged camshaft position actuator filter. If filter is missing, replace the filter, replace the camshaft position actuator, and change the engine oil and oil filter. If filter is plugged, replace the filter, and change the engine oil and oil filter. If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.

IMPORTANT
The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.

Lower Engine Noise, Regardless of Engine Speed

Cause	Correction
Low oil pressure	Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing . 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.	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 knock sensor system. Refer to Electronic Ignition System Diagnosis .
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.
Damaged oil pan, contacting the oil pump screen-An oil pan that has been damaged may improperly position the oil pump screen, preventing proper oil flow to the oil pump.	Inspect the oil pan. Inspect the oil pump screen Repair or replace as required.
Oil pump screen loose, damaged or restricted	Inspect the oil pump screen. 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 The crankshaft journals
Incorrect piston, piston pin and connecting rod installation-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.	Verify the pistons, piston pins and connecting rods are installed correctly. Repair as required.

Engine Noise Under Load

Cause	Correction
IMPORTANT: The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.
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 knock sensor system. Refer to Electronic Ignition System Diagnosis .
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 bore
Malfunctioning camshaft position actuator-Improper viscosity oil, contaminated oil, or a plugged or missing camshaft position actuator filter can cause the camshaft position actuator locking pin to malfunction.	Verify correct oil viscosity by changing the engine oil and oil filter and reevaluating the concern. Inspect for a missing or plugged camshaft position actuator filter. If filter is missing, replace the filter, replace the camshaft position actuator, and change the engine oil and oil filter. If filter is plugged, replace the filter, and change the engine oil and oil filter. If no problem is found with the camshaft position actuator filter, replace the camshaft position actuator and change the engine oil and oil filter.

IMPORTANT
The camshaft position actuator may make a slight tapping noise upon cold startup. This is due to the viscosity of the oil that has not yet warmed to proper operating temperatures, and should be considered normal for the first 3.5 minutes of cold engine operation.

Engine Will Not Crank - Crankshaft Will Not Rotate

Cause	Correction
Seized accessory drive system component	Remove accessory drive belt or belts. Rotate crankshaft by hand at the balancer or flywheel location.
Hydraulically locked cylinder Coolant/antifreeze in cylinder Oil in cylinder Fuel in cylinder	Remove spark plugs and check for fluid. Inspect for broken head gasket or gaskets. Inspect for cracked engine block or cylinder head. Inspect for a sticking fuel injector and/or leaking fuel regulator.
Seized automatic transmission torque converter	Remove the torque converter bolts. Rotate crankshaft by hand at the balancer or flywheel location.
Broken timing chain and/or timing chain gears	Inspect timing chain and gears. Repair as required.
Material in cylinder Broken valve Piston material Foreign material	Inspect cylinder for damaged components and/or foreign materials. Repair or replace as required.
Seized crankshaft or connecting rod bearings	Inspect crankshaft and connecting rod bearings. Repair as required.
Bent or broken connecting rod	Inspect connecting rods. Repair as required.
Broken crankshaft	Inspect crankshaft. Repair as required.

Coolant in Combustion Chamber

Cause	Correction
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. A slower than normal cranking speed may indicate coolant entering the combustion chamber. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate . Remove the spark plugs and inspect for spark plugs saturated by coolant or coolant in the cylinder bore. Inspect by performing a Cylinder Leakage Test . During this test, excessive air bubbles within the coolant may indicate a faulty gasket or damaged component. 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 .
Cracked intake manifold or failed gasket	Replace the components as required.
Warped cylinder head	Machine the cylinder head to the proper flatness, if applicable and 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 cylinder liner or engine block	Replace the components as required.
Cylinder head or engine block porosity	Replace the components as required.

Coolant in Engine Oil

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. 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 . Inspect by performing a Cylinder Leakage Test . During this test, excessive air bubbles within the cooling system may indicate a faulty gasket or damaged component. 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 external engine oil cooler	Replace the components as required.
Warped cylinder head	Machine the cylinder head to proper flatness, if applicable, and 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 cylinder liner or engine block	Replace the components as required.
Cylinder head, or block, porosity	Replace the components as required.

Tools Required

J 38722 Compression Tester. See Special Tools .

Test

A compression pressure test of the engine cylinders determines the condition of the rings, the valves, and the head gasket.

Disable the ignition.
Disable the fuel systems.
Remove the spark plugs from all the cylinders.
Remove the air duct from the throttle body.
Block the throttle plate in the open position.
Measure the engine compression, using the following procedure: Firmly install the compression gauge to the spark plug hole. Have an assistant crank the engine through at least 4 compression strokes in the testing cylinder. Record the readings on the gauge at each stroke. Disconnect the gauge. Repeat the compression test for each cylinder.
Using the J 38722 record the compression readings from all of the cylinders. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) . The lowest reading should not be less than 70 percent of the highest reading. No cylinder reading should be less than 689 kPa (100 psi).
The following list contains examples of the possible measurements: When the compression measurement is normal, the compression builds up quickly and evenly to the specified compression on each cylinder. When the compression is low on the first stroke and tends to build up on the following strokes, but does not reach the normal compression, the piston rings may be the cause. If the compression improves considerably with the addition of 3 squirts of oil, the piston rings may be the cause. When the compression is low on the first stroke and does not build up in the following strokes, the valves may be the cause. The addition of oil does not affect the compression, the valves may be the cause. When the compression is low on 2 adjacent cylinders, or coolant is present in the crankcase, the head gasket may be the cause.
Remove the block from the throttle plate.
Install the air duct to the throttle body.
Install the spark plugs.
Install the powertrain control module (PCM) fuse.
Install the ignition fuse to the I/P fuse block.

Special Tools

J 35667-A: Cylinder Head Leakdown Tester

For equivalent regional tools, refer to Special Tools .

With the use of air pressure, a cylinder leakage test will aid in the diagnosis. Use the cylinder leakage test in conjunction with the engine compression test in order to isolate the cause of leaking cylinders.

Disconnect the negative battery cable.
Remove the spark plugs. Refer to «Spark Plug Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-35l-repair-instructions) .
Install the J 35667-A: tester.
Measure each cylinder on the compression stroke, with both valves closed.
Apply air pressure, using the J 35667-A: tester. Refer to the manufacturer's instructions.
Record the cylinder leakage readings for each cylinder.
Inspect the 4 primary areas in order to properly diagnose a leaking cylinder.
If air is heard from the intake or exhaust system, perform the following procedure: Remove the valve rocker arm cover of the suspect cylinder head. Ensure that both valves are closed. Inspect the cylinder head for a broken valve spring. Remove and inspect the suspect cylinder head. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-off-vehicle-2-of-3) .
If air is heard from the crankcase system at the crankcase - oil filler tube, perform the following procedure: Remove the piston from the suspect cylinder. Inspect the piston and connecting rod assembly. Refer to «Piston, Connecting Rod, and Bearing Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-off-vehicle-1-of-3) . Inspect the engine block. Refer to «Engine Block Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-off-vehicle-1-of-3) .
If bubbles are found in the radiator, perform the following procedure: Remove and inspect both cylinder heads. Refer to «Cylinder Head Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-off-vehicle-2-of-3) . Inspect the engine block. Refer to «Engine Block Cleaning and Inspection»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-repair-instructions-off-vehicle-1-of-3) .
Remove the J 35667-A: tester.
Install the spark plugs. Refer to «Spark Plug Replacement»(/chevrolet/malibu/vii-2008-2012/remont/testing-diagnostics/#engine-controls-and-fuel-35l-repair-instructions) .
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection (LE5, LE9, LZ4, LZE, or LY7)»(/chevrolet/malibu/vii-2008-2012/remont/charging-system/#battery-charging-system-and-starting-system) .

Oil Consumption Diagnosis

An engine that has excessive oil consumption uses 0.9 L (1 qt) of oil, or more, within 3 200 km (2,000 mi). The following list indicates the conditions and corrections of excessive oil consumption

An improperly read oil level indicator dipstick Inspect the oil level while the vehicle is parked on a level surface. Allow adequate drain-down time.
Improper oil viscosity Use the recommended SAE viscosity for prevailing temperatures.
Continuous high-speed driving
Severe hauling, such as a trailer. This causes decreased oil mileage.
A malfunctioning crankcase ventilation system
External oil leaks Tighten the bolts, as needed. Replace the gaskets and seals, as needed.
Worn or omitted valve guides and/or valve stem seals Ream the guides. Install oversized service valves and/or new valve stem seals.
Broken or worn piston rings
Improperly installed or unseated piston rings
Improperly installed or improperly fitted piston
Plugged cylinder head gasket oil drain holes
Damaged intake gaskets

Low or No Oil Pressure

The following conditions may cause low or no oil pressure

Low oil level-Fill to the full mark on the oil level indicator.
Incorrect or malfunctioning oil pressure switch-Replace the oil pressure switch.
Incorrect or malfunctioning oil pressure gauge-Replace the oil pressure gauge.
Improper oil viscosity or diluted oil Install oil of proper viscosity for expected temperature. Install new oil if the oil is diluted.
A worn or dirty oil pump-Clean or replace the oil pump.
A plugged oil filter-Replace the oil filter.
A loose or plugged oil pickup screen-Replace the oil pickup screen.
A hole in the oil pickup tube-Replace the oil pickup tube.
Excessive rod, main, or cam bearing clearance-Replace the bearings.
Cracked, porous, or plugged oil gallery-Repair or replace the engine block.
Missing or improperly installed gallery plugs-Install or repair the plugs as needed.
A stuck pressure regulator valve Inspect the pressure regulator valve for sticking in the bore. Inspect the bore for scoring and burrs.
A worn or poorly machined camshaft-Replace the camshaft.
Worn valve guides-Repair the valve guides as needed.

Oil Pressure Testing

Tools Required

J-21867-6 Oil Pressure Adapter Fitting. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) .
J 25087-C Oil Pressure Tester and Pump Primer. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) .

If the vehicle has low oil pressure complete the following steps

Inspect the oil level.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/malibu/vii-2008-2012/remont/ignition-switchsteering-lock/#general-information) .
Remove the oil filter.
Assemble the plunger valve in the large hole of the J 25087-C base. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) . Insert the hose in the small hole of the J 25087-C base. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) . Connect the gauge to the end of the hose.
Insert the flat side of the rubber plug in the bypass valve without depressing the bypass valve.
Install the J 25087-C and J-21867-6 on the filter mounting pad. See «Special Tools»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-special-tools-and-equipment) .
Start the engine.
Inspect the overall oil pressure, the oil pressure switch, and for noisy lifters. Ensure that the engine is at operating temperature before inspecting the oil pressure. Refer to «Engine Mechanical Specifications»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-specifications__engine-mechanical-specifications) for proper oil pressure specifications.
If adequate oil pressure is indicated, test the oil pressure switch.
If a low reading is indicated, press the valve on the tester base in order to isolate the oil pump and/or its components from the lubricating system. An adequate reading at this time indicates a good pump and the previous low pressure was due to worn bearings, etc. A low reading while pressing the valve indicates a faulty pump.

J 28428-E High Intensity Black Light Kit

You may repair most fluid leaks by first visually locating the leak, repairing or replacing the component, or by resealing the gasket surface. Once the leak is identified, determine the cause of the leak. Repair the leak and the cause of leak.

Locating and Identifying the Leak

Use the visual inspection method in order to determine if the leaking fluid is one of the following items

Engine oil
Transmission fluid
Power steering fluid
Brake fluid
Some other fluid

Visual Inspection Method

Complete the following steps in order to perform the visual inspection method

Bring the vehicle to normal operating temperature.
Park the vehicle over a large sheet of paper, or other clean surface.
Wait several minutes, then inspect for dripping fluids.
Identify the type of fluid, and the approximate location of the leak.
Visually inspect the suspected area. Use a small mirror if necessary.
Inspect for leaks at sealing surfaces, fittings, or from cracked or damaged components.
If you cannot locate the leak, perform the following steps: Completely clean the entire engine and surrounding components. Operate the vehicle for several miles at normal operation temperature and at varying speeds. Park the vehicle over a large sheet of paper, or other clean surface. Wait several minutes, then inspect for dripping fluids. Identify the type of fluid, and the approximate location of the leak. Visually inspect the suspected area. Use a small mirror if necessary.
If you still cannot locate the leak, use the powder method or the black light and dye method.

Powder Method

Completely clean the entire engine and surrounding components.
Apply an aerosol-type powder, baby powder, foot powder, etc., to the suspected area.
Operate the vehicle for several miles at normal operation temperature and at varying speeds.
Identify the type of fluid, and the approximate location of the leak, from the discolorations in the powder surface.
Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas. Refer to «Possible Causes for Leaks»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-35l-diagnostic-information-and-procedures__possible-causes-for-leaks) if necessary.

Black Light and Dye Method

A dye and light kit is available for finding leaks.

Use the J 28428-E or the equivalent. Refer to the manufacturer's instructions when using the tool.
Visually inspect the suspected area. Use a small mirror if necessary Refer to Possible Causes for Leaks below if necessary.

Possible Causes for Leaks

Inspect the vehicle for the following conditions

Higher than recommended fluid levels
Higher than recommended fluid pressures
Plugged or malfunctioning fluid filters or pressure bypass valves
Plugged or malfunctioning engine ventilation system
Improperly tightened or damaged fasteners
Cracked or porous components
Improper sealants or gaskets where required
Improper sealant or gasket installation
Damaged or worn gaskets or seals
Damaged or worn sealing surfaces

Crankcase Ventilation (CV) System Inspection

Test for vacuum at the vacuum hose where it connects to the crankcase ventilation valve or the cylinder head cover. There should be manifold vacuum present at the hose. If there is no vacuum, inspect for a plugged hose, leaking hose or a plugged vent adapter.
Plug the end of the vacuum hose while the engine is running. Inspect the hose for any areas that collapse when the end of the hose is blocked. Replace the hose if it collapses when blocked.
If oil has accumulated in the intake air duct, inspect for the following conditions: Plugged vacuum orifice in the crankcase ventilation housing Plugged or restricted crankcase ventilation housing Excessive crankcase pressure or blow-by, refer to «Oil Consumption Diagnosis»(/chevrolet/malibu/vii-2008-2012/remont/mechanical/#engine-mechanical-36l-diagnostic-information-and-procedures__oil-consumption-diagnosis) .
Additional items to inspect: Plugged or leaking fresh air vent hose assembly or vent adapter Plugged or restricted passages in the throttle body Missing or damaged O-ring seals on the vent adapter Inspect the cam covers, the oil pan gasket, and other sealing areas for leaks

Results of Incorrect Operation

A plugged crankcase ventilation housing or hose may contribute to the following conditions

A rough idle
Stalling or a slow idle speed
Oil leaks
Oil accumulation in the intake air duct
Sludge in the engine

A leaking housing or hose may contribute to the following conditions

A rough idle
Stalling
Unstable idle speed

Diagnostic Aids

A chirping or squeal noise may be intermittent due to moisture on the drive belts or the pulleys. It may be necessary to spray a small amount of water on the drive belts in order to duplicate the customers concern. If spraying water on the drive belt duplicates the symptom, cleaning the belt pulleys may be the probable solution.
If the noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.
A chirping, squeal or whine noise may be caused by a loose or improper installation of a body or suspension component. Other items of the vehicle may also cause the noise.
The drive belts will not cause a whine noise.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: The noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further with this table.
3: The noise may be an internal engine noise. Removing the drive belts one at a time and operating the engine for a brief period will verify the noise is related to the drive belt. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belts removed.
4: Inspect all drive belt pulleys for pilling. Pilling is the small balls or pills or it can be strings in the drive belt grooves from the accumulation of rubber dust.
6: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
10: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed.
12: Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
14: This test is to verify that the drive belt tensioner operates properly. If the drive belt tensioner is not operating properly, proper belt tension may not be achieved to keep the drive belt from slipping which could cause a squeal noise.
15: This test is to verify that the drive belt is not too long, which would prevent the drive belt tensioner from working properly. Also if an incorrect length drive belt was installed, it may not be routed properly and may be turning an accessory drive component in the wrong direction.
16: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
17: This test is to verify that the pulleys are the correct diameter or width. Using a known good vehicle compare the pulley sizes.
19: Replacing the drive belt when it is not damaged or there is not excessive pilling will only be a temporary repair.

Step	Action	Yes	No
CAUTION: Refer to Belt Dressing Caution . DEFINITION: The following items are indications of chirping: A high pitched noise that is heard once per revolution of the drive belt or a pulley. Chirping may occur on cold damp start-ups and will subside once the vehicle reaches normal operating temp. DEFINITION: The following items are indications of drive belt squeal: A loud screeching noise that is caused by a slipping drive belt. This is unusual for a drive belt with multiple ribs. The noise occurs when a heavy load is applied to the drive belt, such as an air conditioning compressor engagement snapping the throttle, or slipping on a seized pulley or a faulty accessory drive component. DEFINITION: The following items are indications of drive belt whine: A high pitched continuous noise. The noise may be caused by an accessory drive component failed bearing.
1	Did you review the Drive Belt Symptom operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Engine Mechanical
2	Verify that there is a chirping, squeal or whine noise. Does the engine make the chirping squeal or whine noise?	Go to Step 3	Go to Diagnostic Aids
3	Remove the drive belt. If the engine has multiple drive belts, remove the belts one at a time and perform the test below each time a belt is removed. Operate the engine for no longer than 30-40 seconds. Repeat this test if necessary by removing the remaining belt(s). Does the chirping, squeal or whine noise still exist?	Go to Symptoms - Engine Mechanical	Go to Step 4
4	If diagnosing a chirping noise, inspect for severe pilling exceeding 1/3 of the belt groove depth. If diagnosing a squeal or whine noise, proceed to step 13. Do the belt grooves have pilling?	Go to Step 5	Go to Step 6
5	Clean the drive belt pulleys with a suitable wire brush. Did you complete the repair?	Go to Step 20	Go to Step 6
6	Inspect for misalignment of the pulleys. Are any of the pulleys misaligned?	Go to Step 7	Go to Step 8
7	Replace or repair any misaligned pulleys. Did you complete the repair?	Go to Step 20	Go to Step 8
8	Inspect for bent or cracked brackets. Did you find any bent or cracked brackets?	Go to Step 9	Go to Step 10
9	Replace any bent or cracked brackets. Did you complete the repair?	Go to Step 20	Go to Step 10
10	Inspect for improper, loose or missing fasteners. Did you find the condition?	Go to Step 11	Go to Step 12
11	CAUTION: Refer to Fastener Caution . Tighten any loose fasteners. Refer to Fastener Tightening Specifications . Replace any improper or missing fasteners. Did you complete the repair?	Go to Step 20	Go to Step 12
12	Inspect for a bent pulley. Did you find the condition?	Go to Step 18	Go to Step 19
13	Inspect for an accessory drive component seized bearing or a faulty accessory drive component. If diagnosing a whine noise and the condition still exist, proceed to Diagnostic Aids. Did you find and correct the condition?	Go to Step 20	Go to Step 14
14	Test the drive belt tensioner for proper operation. Refer to Drive Belt Tensioner Diagnosis . Did you find and correct the condition?	Go to Step 20	Go to Step 15
15	Inspect for the correct drive belt length. Did you find and correct the condition?	Go to Step 20	Go to Step 16
16	Inspect for misalignment of a pulley. Did you find and correct the condition?	Go to Step 20	Go to Step 17
17	Inspect for the correct pulley size. Did you find and correct the condition?	Go to Step 20	Go to Diagnostic Aids
18	Replace the bent pulley. Did you complete the repair?	Go to Step 20	Go to Step 19
19	Replace the drive belt. Refer to Drive Belt Replacement . Did you complete the repair?	Go to Step 20	Go to Diagnostic Aids
20	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3

CAUTION
Refer to Belt Dressing Caution .

CAUTION
Refer to Fastener Caution .

The accessory drive components can have an affect on engine vibration. Vibration from the engine operating may cause a body component or another part of the vehicle to make rumbling noise. Vibration can be caused by, but not limited to the A/C system over charged, the power steering system restricted or the incorrect fluid, or an extra load on the generator. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

The drive belt may have a rumbling condition that can not be seen or felt. Sometimes replacing the drive belt may be the only repair for the symptom.

If replacing the drive belt, completing the diagnostic table, and the noise is only heard when the drive belts are installed, there might be an accessory drive component with a failure. Varying the load on the different accessory drive components may aid in identifying which component is causing the rumbling noise.

The numbers below refer to the step numbers on the diagnostic table.

2: This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
3: This test is to verify that one of the drive belts is causing the rumbling noise or vibration. Rumbling noise may be confused with an internal engine noise due to the similarity in the description. Remove only one drive belt at a time if the vehicle has multiple drive belts. When removing the drive belts the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belts removed.
4: Inspecting the drive belts is to ensure that they are not causing the noise. Small cracks across the ribs of the drive belt will not cause the noise. Belt separation is identified by the plys of the belt separating and may be seen at the edge of the belt our felt as a lump in the belt.
5: Small amounts of pilling is normal condition and acceptable. When the pilling is severe the drive belt does not have a smooth surface for proper operation.
9: Inspecting of the fasteners can eliminate the possibility that the wrong bolt, nut, spacer, or washer was installed.
11: This step should only be performed if the water pump is driven by the drive belt. Inspect the water pump shaft for being bent. Also inspect the water pump bearings for smooth operation and excessive play. Compare the water pump with a known good water pump.
12: Accessory drive component brackets that are bent, cracked, or loose may put extra strain on that accessory component causing it to vibrate.

Step	Action	Yes	No
CAUTION: Refer to Belt Dressing Caution . DEFINITION: The following items are indications of drive belt rumbling: A low pitch tapping, knocking, or thumping noise heard at or just above idle. Heard once per revolution of the drive belt or a pulley. Rumbling may be caused from: Pilling, the accumulation of rubber dust that forms small balls (pills) or strings in the drive belt pulley groove The separation of the drive belt A damaged drive belt DEFINITION: The following items are indications of drive belt vibration: The vibration is engine-speed related. The vibration may be sensitive to accessory load.
1	Did you review the Drive Belt Symptom operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Engine Mechanical
2	Verify that there is a rumbling noise or that the vibration is engine related. Does the engine make the rumbling noise or vibration?	Go to Step 3	Go to Diagnostic Aids
3	Remove the drive belt. If the engine has multiple drive belts, remove the belts one at a time and perform the test below each time a belt is removed. Operate the engine for no longer than 30-40 seconds. Repeat this test if necessary by removing the remaining belt(s). Does the rumbling or vibration still exist?	Go to Symptoms - Engine Mechanical or Go to Vibration Analysis - Engine	Go to Step 4
4	Inspect the drive belts for wear, damage, separation, sections of missing ribs, and debris build-up. Did you find any of these conditions?	Go to Step 7	Go to Step 5
5	Inspect for severe pilling of more than 1/3 of the drive belt pulley grooves. Did you find severe pilling?	Go to Step 6	Go to Step 7
6	Clean the drive belt pulleys using a suitable wire brush. Reinstall the drive belts. Refer to Drive Belt Replacement . Did you correct the condition?	Go to Step 8	Go to Step 7
7	Install a new drive belt. Refer to Drive Belt Replacement . Did you complete the replacement?	Go to Step 8	Go to Step 9
8	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 9
9	Inspect for improper, loose or missing fasteners. Did you find any of these conditions?	Go to Step 10	Go to Step 11
10	CAUTION: Refer to Fastener Caution . Tighten any loose fasteners. Refer to Fastener Tightening Specifications . Replace improper or missing fasteners. Did you complete the repair?	Go to Step 13	Go to Step 11
11	Inspect for a bent water pump shaft. Refer to Water Pump Replacement (LZ4) . Did you find and correct the condition?	Go to Step 13	Go to Step 12
12	Inspect for bent or cracked brackets. Did you find and correct the condition?	Go to Step 13	Go to Diagnostic Aids
13	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3

CAUTION
Refer to Belt Dressing Caution .

CAUTION
Refer to Fastener Caution .

If the drive belt repeatedly falls off the drive belt pulleys, this is because of pulley misalignment.

An extra load that is quickly applied on released by an accessory drive component may cause the drive belt to fall off the pulleys. Verify the accessory drive components operate properly.

If the drive belt is the incorrect length, the drive belt tensioner may not keep the proper tension on the drive belt.

Excessive wear on a drive belt is usually caused by an incorrect installation or the wrong drive belt for the application.

Minor misalignment of the drive belt pulleys will not cause excessive wear, but will probably cause the drive belt to make a noise or to fall off.

Excessive misalignment of the drive belt pulleys will cause excessive wear but may also make the drive belt fall off.

The numbers below refer to the step numbers on the diagnostic table.

2: This inspection is to verify the condition of the drive belt. Damage may of occurred to the drive belt when the drive belt fell off. The drive belt may of been damaged, which caused the drive belt to fall off. Inspect the belt for cuts, tears, sections of ribs missing, or damaged belt plys.
4: Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure of that pulley.
5: Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
6: Accessory drive component brackets that are bent or cracked will let the drive belt fall off.
7: Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed. Missing. loose, or the wrong fasteners may cause pulley misalignment from the bracket moving under load. Over tightening of the fasteners may cause misalignment of the accessory component bracket.
13: The inspection is to verify the drive belt is correctly installed on all of the drive belt pulleys. Wear on the drive belt may be caused by mis-positioning the drive belt by one groove on a pulley.
14: The installation of a drive belt that is two wide or two narrow will cause wear on the drive belt. The drive belt ribs should match all of the grooves on all of the pulleys.
15: This inspection is to verify the drive belt is not contacting any parts of the engine or body while the engine is operating. There should be sufficient clearance when the drive belt accessory drive components load varies. The drive belt should not come in contact with an engine or a body component when snapping the throttle.

Step	Action	Yes	No
CAUTION: Refer to Belt Dressing Caution . DEFINITION: The drive belt falls off the pulleys or may not ride correctly on the pulleys.DEFINITION: Wear at the outside ribs of the drive belt due to an incorrectly installed drive belt.
1	Did you review the Drive Belt Symptom operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Engine Mechanical
2	If diagnosing excessive wear, proceed to step 13. If diagnosing a drive belt that falls off, inspect for a damaged drive belt. Did you find the condition?	Go to Step 3	Go to Step 4
3	Install a new drive belt. Refer to Drive Belt Replacement . Does the drive belt continue to fall off?	Go to Step 4	System OK
4	Inspect for misalignment of the pulleys. Did you find and repair the condition?	Go to Step 12	Go to Step 5
5	Inspect for a bent or dented pulley. Did you find and repair the condition?	Go to Step 12	Go to Step 6
6	Inspect for a bent or a cracked bracket. Did you find and repair the condition?	Go to Step 12	Go to Step 7
7	Inspect for improper, loose or missing fasteners. Did you find loose or missing fasteners?	Go to Step 8	Go to Step 9
8	CAUTION: Refer to Fastener Caution . Tighten any loose fasteners. Refer to Fastener Tightening Specifications . Replace improper or missing fasteners. Does the drive belt continue to fall off?	Go to Step 9	System OK
9	Test the drive belt tensioner for operating correctly. Refer to Drive Belt Tensioner Diagnosis . Does the drive belt tensioner operate correctly?	Go to Step 11	Go to Step 10
10	Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement . Does the drive belt continue to fall off?	Go to Step 11	System OK
11	Inspect for failed drive belt idler and drive belt tensioner pulley bearings. Did you find and repair the condition?	Go to Step 12	Go to Diagnostic Aids
12	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2
13	Inspect the drive belt for the proper installation. Refer to Drive Belt Replacement . Did you find this condition?	Go to Step 16	Go to Step 14
14	Inspect for the proper drive belt. Did you find this condition?	Go to Step 16	Go to Step 15
15	Inspect for the drive belt rubbing against a bracket, hose, or wiring harness. Did you find and repair the condition?	Go to Step 17	Go to Diagnostic Aids
16	Replace the drive belt. Refer to Drive Belt Replacement . Did you complete the replacement?	Go to Step 17
17	Operate the system in order to verify the repair. Did you correct the condition?	System OK

CAUTION
Refer to Belt Dressing Caution .

CAUTION
Refer to Fastener Caution .

Drive Belt Tensioner Diagnosis

Step	Action	Yes	No
1	Remove the drive belt. Inspect the drive belt tensioner pulley. Is the drive belt tensioner pulley loose or misaligned?	Go to Step 4	Go to Step 2
2	Rotate the drive belt tensioner. Does the tensioner rotate without any unusual resistance or binding?	Go to Step 3	Go to Step 4
3	Use a torque wrench in order to measure the torque required to move the tensioner off of the stop. Use a torque wrench on a known good tensioner in order to measure the torque required to move the tensioner off of the stop. Is the first torque reading within 10 percent of the second torque reading?	System OK	Go to Step 4
4	Replace the drive belt tensioner. Refer to Drive Belt Tensioner Replacement . Is the repair complete?	System OK

Engine Mechanical - 3.5l - Diagnostic Information and Procedures Chevrolet Malibu VII

Strategy Based Diagnostics

Visual/Physical Inspection

Intermittent

Symptom List

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire with Coolant Consumption

Base Engine Misfire with Excessive Oil Consumption

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

Upper Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Engine Noise Under Load

Engine Will Not Crank - Crankshaft Will Not Rotate

Coolant in Combustion Chamber

Coolant in Engine Oil

Tools Required

Test

Special Tools

Oil Consumption Diagnosis

Low or No Oil Pressure

Oil Pressure Testing

Locating and Identifying the Leak

Visual Inspection Method

Powder Method

Black Light and Dye Method

Possible Causes for Leaks

Crankcase Ventilation (CV) System Inspection

Results of Incorrect Operation

Diagnostic Aids

Test Description

Drive Belt Tensioner Diagnosis

More articles — Engine

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