Engine Mechanical - 2.0l - Diagnostic Information and Procedures

Strategy Based Diagnostics

Perform the «Diagnostic System Check - Vehicle»(/buick/regal/v-2009-2013/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»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-component-locator) ,, «Engine Component Description (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-description-and-operation) , and «Lubrication Description»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-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 condition. The diagnostic flow is the place to start when repairs are necessary.

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the engine.
Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Inspect 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 ensure 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 (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__base-engine-misfire-without-internal-engine)
«Base Engine Misfire with Abnormal Internal Lower Engine Noises (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-internal)
«Base Engine Misfire with Abnormal Valve Train Noise (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-valve)
«Base Engine Misfire with Coolant Consumption (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__base-engine-misfire-with-coolant-consumption)
«Base Engine Misfire with Excessive Oil Consumption (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__base-engine-misfire-with-excessive-oil)
«Engine Noise on Start-Up, but Only Lasting a Few Seconds (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__engine-noise-on-start-up-but-only)
«Upper Engine Noise, Regardless of Engine Speed (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__upper-engine-noise-regardless-of-engine)
«Lower Engine Noise, Regardless of Engine Speed (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__lower-engine-noise-regardless-of-engine)
«Engine Noise Under Load (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__engine-noise-under-load-ldk-lhu)
«Engine Will Not Crank - Crankshaft Will Not Rotate (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft)
«Coolant in Combustion Chamber (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__coolant-in-combustion-chamber-ldk-lhu)
«Coolant in Engine Oil (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__coolant-in-engine-oil-ldk-lhu)
«Turbocharger Whine Noise (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-whine-noise-ldk-lhu)
«Turbocharger Hissing Noise (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-hissing-noise-ldk-lhu)
«Turbocharger Oil Leak From Compressor Seal (LDK. LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-oil-leak-from-compressor-seal)
«Turbocharger Oil Leak From Turbine Seal (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-oil-leak-from-turbine-seal)
«Turbocharger Lack of Oil Supply (LDK. LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__turbocharger-lack-of-oil-supply-ldk)
«Engine Compression Test»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__engine-compression-test)
«Cylinder Leakage Test»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__cylinder-leakage-test)
«Oil Consumption Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__oil-consumption-diagnosis)
«Oil Pressure Diagnosis and Testing»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__oil-pressure-diagnosis-and-testing)
«Oil Leak Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__oil-leak-diagnosis)
«Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis-with-turboc)
«Drive Belt Chirping, Squeal, and Whine Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures)
«Drive Belt Rumbling and Vibration Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures)
«Drive Belt Falls Off and Excessive Wear Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures)
«Drive Belt Tensioner Diagnosis»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis)

Base Engine Misfire without Internal Engine Noises (LDK, LHU)

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 and lead to a misfire DTC. A misfire code may be present without an actual misfire condition.	Replace the drive belt.
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.
A 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.
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.
Improperly installed or leaking charge air cooler tube	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.
Improperly installed or damaged manifold absolute pressure (MAP) sensor or intake air pressure temp (TMAP) sensor The sealing grommet of the MAP sensor should not be torn or damaged.	Repair or replace the MAP sensor and/or the TMAP sensor, as required.
Damage to the MAP sensor housing	Replace the intake manifold.
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.
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.
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 Coolant consumption may or may not cause the engine to overheat.	Inspect for spark plugs saturated by coolant. 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. 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.
A damaged crankshaft reluctor wheel A damaged crankshaft reluctor wheel can result in different symptoms depending on the severity and location of the damage. Systems with electronic communications, DIS or coil per cylinder, and severe reluctor ring damage may exhibit periodic loss of crankshaft position, stop delivering a signal, and then re-sync the crankshaft position. Systems with electronic communication, DIS or coil per cylinder, and slight reluctor ring damage may exhibit no loss of crankshaft position and no misfire may occur. However, a DTC P0300 may be set. Systems with mechanical communications, high voltage switch, and severe reluctor ring damage may cause additional pulses and affect fuel and spark delivery to the point of generating a DTC P0300 or P0336.	Replace the sensor and/or crankshaft, as required.

Base Engine Misfire without Internal Engine Noises (LDK, LHU)

Base Engine Misfire with Abnormal Internal Lower Engine Noises (LDK, LHU)

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.
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 the components, 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.
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.
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 Internal Lower Engine Noises (LDK, LHU)

Base Engine Misfire with Abnormal Valve Train Noise (LDK, LHU)

Cause	Correction
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.
Stuck valves Carbon buildup on the valve stem can cause the valve to not 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 lash adjusters.
Sticking lifters	Replace as required.
Malfunctioning camshaft position actuators - improper oil viscosity or contamination.	Verify correct oil pressure. If low, inspect the bottom of the oil filter for oil filter drain back feature. Refer to Oil Pressure Diagnosis and Testing . Isolate the noise to a specific camshaft position actuator. Disconnect the electrical connector on the camshaft position actuator solenoid valves and start the vehicle. If noise is gone, repeat procedure to limit to an individual actuator. Refer to Camshaft Position Intake Actuator Replacement , or Camshaft Position Exhaust Actuator Replacement .

Base Engine Misfire with Abnormal Valve Train Noise (LDK, LHU)

Base Engine Misfire with Coolant Consumption (LDK, LHU)

Cause	Correction
Faulty cylinder head gasket and/or cracking, or other damage to the cylinder head and engine block cooling system passages. Coolant consumption may or may not cause the engine to overheat.	Inspect for spark plugs saturated by coolant. Perform a cylinder leak down test. Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket. Repair or replace as required.

Base Engine Misfire with Coolant Consumption (LDK, LHU)

Base Engine Misfire with Excessive Oil Consumption (LDK, LHU)

Cause	Correction
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.

Base Engine Misfire with Excessive Oil Consumption (LDK, LHU)

Engine Noise on Start-Up, but Only Lasting a Few Seconds (LDK, LHU)

Cause	Correction
Incorrect oil filter without anti-drainback feature	Install the correct oil filter.
Incorrect oil viscosity	Drain the oil. Install the correct viscosity oil.
High valve lash adjuster leak down rate	Replace the lash adjusters as required.
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.
Malfunctioning camshaft position actuators - improper oil viscosity or contamination.	Verify correct oil pressure. If low, inspect the bottom of the oil filter for oil filter drain back feature. Refer to Oil Pressure Diagnosis and Testing . Isolate the noise to a specific camshaft position actuator. Disconnect the electrical connector on the camshaft position actuator solenoid valves and start the vehicle. If noise is gone, repeat procedure to limit to an individual actuator. Refer to Camshaft Position Intake Actuator Replacement , or Camshaft Position Exhaust Actuator Replacement .

Engine Noise on Start-Up, but Only Lasting a Few Seconds (LDK, LHU)

Upper Engine Noise, Regardless of Engine Speed (LDK, LHU)

Cause	Correction
Low oil pressure	Perform an oil pressure test. Refer to 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.
Improper lubrication to the valve rocker arms	Inspect the following components and repair or replace, as required: The valve rocker arm 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 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, damaged, or faulty timing chain tensioners	Replace the timing chain tensioners.
Worn engine camshaft lobes	Inspect the engine camshaft lobes. Replace the camshaft and valve lifters, 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

Upper Engine Noise, Regardless of Engine Speed (LDK, LHU)

Lower Engine Noise, Regardless of Engine Speed (LDK, LHU)

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 ignition system. Refer to Symptoms - 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.
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.

Lower Engine Noise, Regardless of Engine Speed (LDK, LHU)

Engine Noise Under Load (LDK, LHU)

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. Refer to Symptoms - 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 bore
Malfunctioning camshaft position actuators - improper oil viscosity or contamination.	Verify correct oil pressure. If low, inspect the bottom of the oil filter for oil filter drain back feature. Refer to Oil Pressure Diagnosis and Testing . Isolate the noise to a specific camshaft position actuator. Disconnect the electrical connector on the camshaft position actuator solenoid valves and start the vehicle. If noise is gone, repeat procedure to limit to an individual actuator. Refer to Camshaft Position Intake Actuator Replacement , or Camshaft Position Exhaust Actuator Replacement .

Engine Noise Under Load (LDK, LHU)

Engine Will Not Crank - Crankshaft Will Not Rotate (LDK, LHU)

Cause	Correction
Seized accessory drive system component	Remove accessory drive 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. Inspect for cracked engine block or cylinder head. Inspect for a sticking fuel injector. Inspect for cracked cylinder wall.
Seized automatic transmission torque converter	Remove the torque converter bolts. Rotate crankshaft by hand at the balancer or flywheel location.
Seized manual transmission	Disengage the clutch. Rotate crankshaft by hand at the balancer or flywheel location.
Broken timing chain and/or gears	Inspect timing chain and gears. Repair as required.
Seized balance shaft	Inspect balance shaft. Repair as required.
Material in cylinder Broken valve Piston material Foreign material Cracked cylinder wall	Inspect cylinder for damaged components and/or foreign materials. Inspect for fallen cylinder wall. Repair or replace as required.
Seized crankshaft or connecting rod bearings	Inspect crankshaft and connecting rod bearings. Inspect for fallen cylinder wall. Repair as required.
Bent or broken connecting rod	Inspect connecting rods. Repair as required.
Broken crankshaft	Inspect crankshaft. Repair as required.

Engine Will Not Crank - Crankshaft Will Not Rotate (LDK, LHU)

Coolant in Combustion Chamber (LDK, LHU)

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 (LDK, LHU) . Remove the spark plugs and inspect for spark plugs saturated by coolant or coolant in the cylinder bore. Inspect by performing a cylinder leak down 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 .
Faulty cylinder head gasket	Replace the head gasket and components, as required. Refer to Cylinder Head Cleaning and Inspection (LDK, LHU) , and Cylinder Head Replacement .
Warped cylinder head	Replace the cylinder head and gasket. Refer to Cylinder Head Cleaning and Inspection (LDK, LHU) .
Cracked cylinder head	Replace the cylinder head and gasket.
Cracked cylinder liner	Replace the components, as required.
Cylinder head or block porosity	Replace the components, as required.

Coolant in Combustion Chamber (LDK, LHU)

Coolant in Engine Oil (LDK, LHU)

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 (LDK, LHU) . 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. 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 (LDK, LHU) , and Cylinder Head Replacement .
Warped cylinder head	Replace the cylinder head and gasket. Refer to Cylinder Head Cleaning and Inspection (LDK, LHU) .
Cracked cylinder head	Replace the cylinder head and gasket.
Cracked cylinder liner	Replace the components, as required.
Cylinder head or block porosity	Replace the components, as required.

Coolant in Engine Oil (LDK, LHU)

Turbocharger Whine Noise (LDK, LHU)

Condition	Action
Some whine noise is normal. Compare to a known good vehicle.
Worn turbocharger bearings	Visually inspect for evidence of compressor wheel to housing contact. Inspect for worn or damaged turbocharger bearings. Inspect for end play causing compressor wheel to housing contact.

Turbocharger Whine Noise (LDK, LHU)

Turbocharger Hissing Noise (LDK, LHU)

Condition	Action
Air inlet leaks or obstructions	Inspect for leaks or obstructions in the turbocharger inlet.
Leaking or restricted exhaust system	Inspect for a leak in the exhaust system. Inspect for a restricted exhaust system.
Intake system leaks or obstructions	Inspect for leaks. Inspect for obstructions.

Turbocharger Hissing Noise (LDK, LHU)

Turbocharger Oil Leak From Compressor Seal (LDK. LHU)

Condition	Action
Restricted air system	Inspect for a clogged air filter element or restricted air inlet system.
Restricted exhaust system	Inspect for a restricted exhaust.
Leaking exhaust system	Inspect for exhaust manifold leaks.
Poor oil drainage from turbocharger	Inspect for a restricted turbocharger oil drain pipe.
Restricted crankcase ventilation system	Inspect for a restricted crankcase ventilation system.
Worn internal engine components	Inspect for excessive blowby or engine oil consumption.

Turbocharger Oil Leak From Compressor Seal (LDK. LHU)

Turbocharger Oil Leak From Turbine Seal (LDK, LHU)

Condition	Action
Poor oil drainage from turbocharger	Inspect for a restricted turbocharger oil drain pipe.
Restricted crankcase ventilation system	Inspect for a restricted crankcase ventilation system.
Worn internal engine components	Inspect for excessive blowby or engine oil consumption.

Turbocharger Oil Leak From Turbine Seal (LDK, LHU)

Turbocharger Lack of Oil Supply (LDK. LHU)

Condition	Action
Restricted oil supply hose	Inspect for a restricted or damaged turbocharger oil supply hose.

Turbocharger Lack of Oil Supply (LDK. LHU)

Engine Compression Test

Charge the battery if the battery is not fully charged.
Disable the ignition system.
Disable the fuel injection system.
Remove all spark plugs.
Turn the ignition to the ON position.
Depress the accelerator pedal to position the throttle plate wide open.
Start with the compression gauge at zero and crank the engine through 4 compression strokes, 4 puffs.
Measure the compression for each cylinder. Record the readings.
If a cylinder has low compression, inject approximately 15 ml (1 tablespoon) of engine oil into the combustion chamber through the spark plug hole. Measure the compression again and record the reading.
The minimum compression in any 1 cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 690 kPa (100 psi). For example, if the highest pressure in any 1 cylinder is 1 035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). (1 035 x 70% = 725) (150 x 70% = 105). Normal - Compression builds up quickly and evenly to the specified compression for each cylinder. Piston Rings Leaking - Compression is low on the first stroke. Compression builds up with the following strokes, but does not reach normal. Compression improves considerably when you add oil. Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does not improve much when you add oil. If 2 adjacent cylinders have lower than normal compression, and injecting oil into the cylinders does not increase the compression, the cause may be a head gasket leaking between the cylinders.

Cylinder Leakage Test

Special Tools

EN-35667-A Cylinder Head Leakdown Tester

For equivalent regional tools, refer to Special Tools (LDK, LHU) .

Note. A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High leakage may indicate one or more of the following conditions

Worn or burnt valves
Broken valve springs
Stuck valve lifters
Incorrect valve lash/adjustment
Damaged piston
Worn piston rings
Worn or scored cylinder bore
Damaged cylinder head gasket
Cracked or damaged cylinder head
Cracked or damaged engine block

Disconnect the battery ground negative cable.
Remove the spark plugs. Refer to «Spark Plug Replacement»(/buick/regal/v-2009-2013/remont/testing-diagnostics/#engine-controlsfuel-20l-repair-instructions) .
Rotate the crankshaft to place the piston in the cylinder being tested at top dead center (TDC) of the compression stroke.
Install the EN-35667-A Tester or equivalent.
Apply shop air pressure to the EN-35667-A Tester and adjust according to the manufacturers instructions.
Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions: Air leakage sounds at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage sounds at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
Perform the leakage test on the remaining cylinders and record the values.

Oil Consumption Diagnosis

Excessive oil consumption, not due to leaks, is the use of 0.9 L (1 qt) or greater of engine oil within 3 200 kilometers (2, 000 miles). The causes of excessive oil consumption include the following conditions

External oil leaks Tighten bolts and/or replace gaskets and oil seals as necessary.
Incorrect oil level or improper reading of oil level indicator With the vehicle on a level surface, allow adequate drain down time and inspect for the correct oil level.
Improper oil viscosity Use recommended SAE viscosity for the prevailing temperatures.
Continuous high speed driving and/or severe usage
Crankcase ventilation system restrictions or malfunctioning components
Valve guides and/or valve stem oil seals worn, or the seal omitted Ream guides and install oversize service valves and/or new valve stem oil seals.
Piston rings broken, improperly installed, worn, or not seated properly Allow adequate time for rings to seat. Replace broken or worn rings, as necessary.
Piston improperly installed or mis-fitted

Oil Pressure Diagnosis and Testing

With the vehicle on a level surface, allow adequate drain down time of 2-3 minutes and measure for a low oil level.
Add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
Run the engine, and verify low, or no oil pressure on the vehicle gauge or light.
Listen for a noisy valve train or a knocking noise.
Inspect for the following conditions: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil diluted by moisture or unburned fuel mixtures Improper oil viscosity for the expected temperature Incorrect or malfunctioning oil pressure sender Incorrect or malfunctioning oil pressure gauge Plugged oil filter Malfunctioning oil bypass valve
Remove the oil pressure sender or another engine block oil gallery plug.
Install an oil pressure gauge and measure the engine oil pressure.
Compare the readings to the specifications. Refer to «Engine Mechanical Specifications (LDK, LHU)»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-specifications__engine-mechanical-specifications-ldk-lhu) .
If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil pump worn or dirty Refer to «Oil Pump Disassemble»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__oil-pump-disassemble) . Oil pump-to-engine front cover bolts loose Refer to «Engine Front Cover and Oil Pump Installation»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__engine-front-cover-and-oil-pump) . Oil pump screen loose, plugged, or damaged Oil pump screen O-ring seal missing or damaged Malfunctioning oil pump pressure regulator valve Excessive bearing clearance Refer to «Crankshaft and Bearing Cleaning and Inspection»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__crankshaft-and-bearing-cleaning-and-inspection) . Cracked, porous or restricted oil galleries Oil gallery plugs missing or incorrectly installed Refer to «Engine Block Assemble»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-20l-repair-instructions-off-vehicle__engine-block-assemble) . Broken lash adjusters

Oil Leak Diagnosis

Step	Action	Yes	No
DEFINITION: You can 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 cause of the leak as well as the leak itself.
1	Operate the vehicle until it reaches normal operating temperature. Refer to Engine Mechanical Specifications (LDK, LHU) . Park the vehicle on a level surface, over a large sheet of paper or other clean surface. Wait 15 minutes. Inspect for drippings. Are drippings present?	Go to Step 2	System OK
2	Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 3
3	Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas. Inspect for leaks at the following locations: Sealing surfaces Fittings Cracked or damaged components Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 4
4	Completely clean the entire engine and surrounding components. Operate the vehicle for several miles at normal operating temperature and at varying speeds. Park the vehicle on a level surface, over a large sheet of paper or other clean surface. Wait 15 minutes. Identify the type of fluid, and the approximate location of the leak. Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 5
5	Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas. Inspect for leaks at the following locations: Sealing surfaces Fittings Cracked or damaged components Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 6
6	Completely clean the entire engine and surrounding components. Apply an aerosol-type powder, for example, baby powder or foot powder, to the suspected area. Operate the vehicle for several miles at normal operating temperature and at varying speeds. Identify the type of fluid, and the approximate location of the leak, from the discolorations in the powder surface. Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 7
7	Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas. Inspect for leaks at the following locations: Sealing surfaces Fittings Cracked or damaged components Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 8
8	Use the J 28428-E high-intensity black light kit in order to identify the type of fluid, and the approximate location of the leak. Refer to the manufacturer's instructions when using the tool. Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	Go to Step 9
9	Visually inspect the suspected area. Use a small mirror to assist in looking at hard to see areas. Inspect for leaks at the following locations: Sealing surfaces Fittings Cracked or damaged components Can you identify the type of fluid and the approximate location of the leak?	Go to Step 10	System OK
10	Inspect the engine for mechanical damage. Special interest should be shown to the following areas: 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 Inspect the engine for customer modifications. Is there mechanical damage, or customer modifications to the engine?	Go to Step 11	System OK
11	Repair or replace all damaged or modified components. Did you replace all damaged or modified components, as necessary?	Go to Step 1

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)

Special Tools

J 23951 Valve Manometer

Verify clean air cleaner.
Verify oil fill cap is in place.
Verify oil level indicator is installed.
Remove the oil level indicator. Install a manometer «J 23951»(/buick/regal/v-2009-2013/remont/mechanical/#engine-mechanical-24l) , or equivalent, into the oil level indicator tube.
Start the engine.
The vacuum of the column of water at idle should be from 3-4 1/2 inches column height.
If vacuum is higher inspect and verify the clean air hose from cam cover to air inlet is not blocked or kinked, and the check valve on the clean air hose is open when vacuum from the engine is applied. Also inspect for missing or damaged PCV orifice in the intake manifold.
The hose from valve cover to the turbo is also for the positive crankcase ventilation (PCV) and is used for PCV flow under normal operation and only PCV flow during turbo boost conditions. If the hose is plugged, this will raise vacuum. Diagnosis can be done by removing the turbo side of the hose and start the engine for a few seconds. This should create a large air leak and erratic idle showing there is air flow. If the hose is blocked manually, vacuum will increase.
If vacuum is in normal range, block or pinch off the clean air hose. The clean air hose is the hose between the cam cover and air intake system. Vacuum should increase to approximately 5 inches on the manometer. If held too long, damage could result to the sealing system.
If vacuum does not increase, the orifice with check valve in the center of the intake manifold face could be plugged.
If there is zero vacuum or pressure, verify compression of the engine.
If compression is normal, check for a blocked orifice with check valve at the intake manifold clean orifice.

Concern	Action
External oil leak	Inspect for any of the following conditions: Plugged air intake system Plugged positive crankcase ventilation (PCV) orifice/check valve in the intake manifold Plugged or kinked PCV hoses Damaged or incorrectly installed PCV hoses Excessive crankcase pressure Plugged PCV hose from cam cover to turbo
Rough idle	Inspect for any of the following conditions: Plugged or incorrectly installed air intake system Plugged PCV orifice/check valve in the intake manifold Plugged or kinked PCV hoses Leaking or damaged PCV hoses Leaking PCV hose from cam cover to turbo
Stalling or slow idle speed	Inspect for any of the following conditions: Plugged air intake system Plugged PCV orifice in the intake manifold Plugged or kinked PCV hoses Leaking or damaged PCV hoses Leaking PCV hose from cam cover to turbo
High idle speed	Inspect for any of the following conditions: Air inlet system properly connected Leaking or damaged PCV hoses
Sludge in the engine	Inspect for any of the following conditions: Plugged or incorrectly installed air intake system Plugged PCV orifice in the intake manifold Plugged or kinked PCV hoses Plugged PCV hose from cam cover to turbo

Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)

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 two or three 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 two or three 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 (LAF, LEA, or LUK) . 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 (LEA) , Drive Belt Replacement (LUK) . 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 .

Drive Belt Chirping, Squeal, and Whine Diagnosis

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 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 (LEA) , Drive Belt Replacement (LUK) . Did you correct the condition?	Go to Step 8	Go to Step 7
7	Install a new drive belt. Refer to Drive Belt Replacement (LEA) , Drive Belt Replacement (LUK) . 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 (LAF, LEA, or LUK) . 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 (L4) . 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 .

Drive Belt Rumbling and Vibration Diagnosis

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 2 or 3 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 too wide or too 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 (LEA) , Drive Belt Replacement (LUK) . 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 (LAF, LEA, or LUK) . 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 Replacement (LEA) , Drive Belt Replacement (LUK) . 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 Replacement (LEA) , Drive Belt Replacement (LUK) . 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 (LEA) , Drive Belt Replacement (LUK) . 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 (LEA) , Drive Belt Replacement (LUK) . 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 Falls Off and Excessive Wear Diagnosis

Drive Belt Tensioner Diagnosis

Step	Action	Yes	No
1	Remove the drive belt. Refer to Drive Belt Replacement (LEA) , Drive Belt Replacement (LUK) . 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 (LUK) , Drive Belt Tensioner Replacement (LEA) . Is the repair complete?	System OK

Drive Belt Tensioner Diagnosis

Engine Mechanical - 2.0l - Diagnostic Information and Procedures Buick Regal V

Strategy Based Diagnostics

Visual/Physical Inspection

Intermittent

Symptom List

Base Engine Misfire without Internal Engine Noises (LDK, LHU)

Base Engine Misfire with Abnormal Internal Lower Engine Noises (LDK, LHU)

Base Engine Misfire with Abnormal Valve Train Noise (LDK, LHU)

Base Engine Misfire with Coolant Consumption (LDK, LHU)

Base Engine Misfire with Excessive Oil Consumption (LDK, LHU)

Engine Noise on Start-Up, but Only Lasting a Few Seconds (LDK, LHU)

Upper Engine Noise, Regardless of Engine Speed (LDK, LHU)

Lower Engine Noise, Regardless of Engine Speed (LDK, LHU)

Engine Noise Under Load (LDK, LHU)

Engine Will Not Crank - Crankshaft Will Not Rotate (LDK, LHU)

Coolant in Combustion Chamber (LDK, LHU)

Coolant in Engine Oil (LDK, LHU)

Turbocharger Whine Noise (LDK, LHU)

Turbocharger Hissing Noise (LDK, LHU)

Turbocharger Oil Leak From Compressor Seal (LDK. LHU)

Turbocharger Oil Leak From Turbine Seal (LDK, LHU)

Turbocharger Lack of Oil Supply (LDK. LHU)

Engine Compression Test

Cylinder Leakage Test

Oil Consumption Diagnosis

Oil Pressure Diagnosis and Testing

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis (With Turbocharger)

Diagnostic Aids

Test Description

Drive Belt Tensioner Diagnosis

More articles — Engine

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