Engine Mechanical - 6.2l - Diagnostic Information and Procedures

Strategy Based Diagnostics

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/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»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-component-locator) , «Engine Component Description»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-description-and-operation) , «Lubrication Description»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-description-and-operation) , and «Drive Belt System Description»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-30l-or-36l-description-and-operation__drive-belt-system-description) .

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. 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»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#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.
Inspect for the correct oil level, proper oil viscosity, and correct oil filter.
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»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__base-engine-misfire-without-internal-engine)
«Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-internal)
«Base Engine Misfire with Abnormal Valve Train Noise»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-valve)
«Base Engine Misfire with Coolant Consumption»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__base-engine-misfire-with-coolant-consumption)
«Base Engine Misfire with Excessive Oil Consumption»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__base-engine-misfire-with-excessive-oil)
«Engine Noise on Start-Up, but Only Lasting a Few Seconds (6.2L)»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__engine-noise-on-start-up-but-only)
«Supercharger Noise Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__supercharger-noise-diagnosis)
«Upper Engine Noise, Regardless of Engine Speed»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__upper-engine-noise-regardless-of-engine)
«Lower Engine Noise, Regardless of Engine Speed»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__lower-engine-noise-regardless-of-engine)
«Engine Noise Under Load»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__engine-noise-under-load)
«Engine Will Not Crank - Crankshaft Will Not Rotate»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft)
«Coolant in Combustion Chamber»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__coolant-in-combustion-chamber)
«Coolant in Engine Oil»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__coolant-in-engine-oil)
«Engine Compression Test»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__engine-compression-test)
«Engine Balancing»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__engine-balancing)
«Cylinder Leakage Test»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures)
«Oil Consumption Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__oil-consumption-diagnosis)
«Oil Pressure Diagnosis and Testing»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__oil-pressure-diagnosis-and-testing)
«Oil Leak Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__oil-leak-diagnosis)
«Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis)
«Drive Belt Chirping, Squeal, and Whine Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures)
«Drive Belt Rumbling and Vibration Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures)
«Drive Belt Falls Off and Excessive Wear Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures)
«Drive Belt Tensioner Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis)

Base Engine Misfire without Internal Engine Noises

Cause	Correction
Fuel injector harness connectors are connected to the incorrect fuel injectors/cylinders	Relocate the fuel injector harness connectors, as necessary.
Abnormalities, such as 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 Replacement - Accessory .
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.
Improperly installed or damaged manifold absolute pressure (MAP) sensor The sealing grommet of the MAP sensor should not be torn or damaged.	Repair or replace the MAP sensor, as required.
Worn or loose rocker arms The rocker arm bearing end caps and/or needle bearings should be intact and the rocker arm in the proper position.	Replace the valve rocker arms, as required.
Worn or bent pushrods	Replace the pushrods. Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.
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. Refer to Spark Plug Inspection . Inspect the cylinder heads, engine block, and/or head gaskets. Refer to Coolant in Combustion Chamber . 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. Refer to Cylinder Leakage Test . 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 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 DTC P0336.	Replace the sensor and/or crankshaft, as required.

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Cause	Correction
Abnormalities, such as 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 Replacement - Accessory .
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 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 .
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. Refer to Cylinder Leakage Test . 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
Worn or loose rocker arms The rocker arm bearing end caps and/or needle bearings should be intact within the rocker arm assembly.	Replace the valve rocker arms, as required.
Worn or bent pushrods	Replace the pushrods. Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.
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.

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 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. Refer to Cylinder Leakage Test . Inspect the cylinder heads and engine block for damage to the coolant passages and/or a faulty head gasket. Refer to Coolant in Combustion Chamber . Repair or replace, as required.
Supercharger intercooler - internal coolant leak - 6.2L LSA	Inspect for a leaking intercooler. Perform a pressure test on the intercooler. Refer to Supercharger Assemble . Repair or replace components 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. Refer to Cylinder Leakage Test . Repair or replace, as required.

Engine Noise on Start-Up, but Only Lasting a Few Seconds (6.2L)

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 lifter leak down rate	Replace the lifters as required.
Worn crankshaft thrust bearing	Check the crankshaft end play. Inspect the thrust bearing and crankshaft. Repair or replace as required.
Faulty oil filter bypass valve. The valve is now internal to the oil filter.	Replace the oil filter as required.

Supercharger Noise Diagnosis

Cause	Correction
Whine	Whine noise is typical of all superchargers and is not a reason to replace the supercharger or other components. Supercharger whine, inherent to the Roots design, results from eight pulses per engine revolution, 2:1 drive ratio x 4 lobes. Air induction system structure and acoustic resonators are designed to minimize whine.
Whistle	A whistle noise is generated by tooth contact of the spur gears between the rotors. For instance, a low level whistle may occur at 2,300-2,800 RPM at 80 percent load driving up a very long grade. Although most of these conditions are addressed by sound path isolation to the passenger compartment, some can still be heard by a very critical ear.
Supercharger rattle - growl	Supercharger growl may be heard at low speed or idle, with the engine under light load. Minuscule crankshaft speed variations, influenced by the torque converter, transmission, drive shaft, differential, and tires, are transmitted through the flexible drive belt to the supercharger. Operating in very thin air, the rotors oscillate and cause the load to alternate from the drive to driven sides of the gear teeth, even precision parts have operating clearances. The entire supercharger drive system is tuned to minimize this noise.
Internal isolator	The supercharger incorporates an internal isolator between the pulley and the rotor shaft, which has two functions. The first is to minimize a knocking sound when the engine is turned off and the mass of the supercharger rotor set is suddenly jerked to a stop. And second, the isolator is tuned to minimize the normal engine firing pulses passed on to the supercharger rotor drive gears. It is active only in an unloaded condition, low engine speed point where boost is not requested. If the engine or one of the components in the driveline is not operating to design intent, the isolator may make a harsh intermittent rattle sound that often goes through cycles as the engine speed or other conditions change slightly.

Upper 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, as required.
Loose and/or worn valve rocker arm attachments	Inspect the valve rocker arm, bolt, and pedestal. Repair or replace, as required.
Worn or damaged valve rocker arm	Inspect the rocker arm for wear or missing needle bearings Replace the valve rocker arms, as required.
Bent or damaged push rod	Inspect the following components and replace, as required: The valve rocker arm The valve push rod The valve lifter The valve lifter guide The piston Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.
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 bypass valve is now internal to the oil filter. The oil pump and pump screen The engine block oil galleries
Broken valve spring	Replace the valve spring and spring shim.
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 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

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 ignition controls system. Refer to Symptoms - Engine Controls .
Loose or damaged flywheel	Repair or replace the flywheel.
Oil pump screen loose, damaged, or restricted	Inspect the oil pump screen. Repair or replace as required.
Excessive piston-to-cylinder bore clearance	Inspect the piston and cylinder bore. Repair, as required.
Excessive piston pin-to-bore clearance	Inspect the piston, pin, and connecting rod. Replace the piston and pin as an assembly, 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. Refer to Piston, Connecting Rod, and Bearing Installation (6.2L) . Repair, as required.

Engine Noise Under Load

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 controls. Refer to Diagnostic System Check - Vehicle .
Loose torque converter bolts	Inspect the torque converter bolts and flex plate. Repair, as required.
Cracked flex plate - automatic transmission	Inspect the bolts and flex plate. 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

Engine Will Not Crank - Crankshaft Will Not Rotate

Cause	Correction
Seized accessory drive system component	Remove the accessory drive belts. Confirm that the engine will rotate. Rotate the crankshaft by hand at the crankshaft balancer or flywheel location. Repair or replace the components, as required.
Seized supercharger - 6.2L LSA	Remove the accessory drive belt and confirm the pulley of the supercharger will rotate. Repair or replace components as required.
Broken timing chain	Inspect the timing chain and sprockets. Repair or replace the components, as required.
Seized timing chain or timing sprockets	Inspect the timing chain and sprockets for foreign material or a seized chain. Repair or replace the components, as required.
Seized or broken camshaft	Inspect the camshaft and the camshaft bearings. Repair or replace the components, as required.
Bent valve in the cylinder head	Inspect the valves and the cylinder heads. Repair or replace the components, as required.
Seized oil pump	Inspect the oil pump assembly. Repair or replace, as required.
Hydraulically locked cylinder Coolant/antifreeze in the cylinder Oil in the cylinder Fuel in the cylinder	Remove spark plugs and inspect for fluid in the cylinder. When rotating the engine with the spark plugs removed, the piston, on compression stroke, will push fluid from the combustion chamber. Refer to Coolant in Combustion Chamber . Inspect for failed/broken head gaskets. Inspect for a cracked engine block or cylinder head. Inspect for a sticking fuel injector. Inspect the supercharger intercooler for an internal coolant leak - 6.2L. Refer to Supercharger Assemble . Repair or replace the components, as required.
Material in the cylinder Broken valve Broken piston rings Piston material Foreign material	Inspect the cylinder for damaged components and/or foreign materials. Repair or replace the components, as required.
Seized crankshaft or connecting rod bearings	Inspect crankshaft and connecting rod bearings. Repair or replace the components, as required.
Bent or broken connecting rod	Inspect the connecting rods. Replace the components, as required.
Broken crankshaft	Inspect the crankshaft. Repair or replace the components, 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 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 and Cylinder Head Replacement - Left Side (LSA) or Cylinder Head Replacement - Right Side (LSA) .
Warped cylinder head	Machine the cylinder head to the proper flatness, if applicable and replace the cylinder head gasket. Refer to Cylinder Head Cleaning and Inspection .
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.
Supercharger intercooler - internal coolant leak - 6.2L LSA	Inspect for a leaking intercooler. Perform a pressure test on the intercooler. Refer to Supercharger Assemble . Repair or replace 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 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 .
Supercharger intercooler with an internal coolant leak - 6.2L LSA	Inspect the supercharger intercooler for an internal coolant leak. Refer to Supercharger Assemble .
Faulty engine oil cooler - 6.2L LSA	Inspect the engine oil cooler for an internal coolant leak. Refer to Engine Oil Cooler Cleaning and Inspection .
Faulty cylinder head gasket	Replace the head gasket and components, as required. Refer to Cylinder Head Cleaning and Inspection and Cylinder Head Replacement - Left Side (LSA) or Cylinder Head Replacement - Right Side (LSA) .
Warped cylinder head	Machine the cylinder head to proper flatness, if applicable, and replace the cylinder head gasket. Refer to Cylinder Head Cleaning and Inspection .
Cracked cylinder head	Replace the cylinder head and gasket.
Cracked cylinder liner or engine block	Replace the components, as required.
Cylinder head, block, or manifold porosity	Replace the components, as required.

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.

Engine Balancing

During the powertrain build process, balance weights may be added to the crankshaft balancer and/or manual transmission flywheel, as required.

In order to maintain engine/clutch assembly balance, it may be necessary to install or remove balance weights as detailed below

Crankshaft Balancer

Existing RPO-LSA manual transmission applications, balancer onto existing engine: It is not necessary to mark the balancer prior to removal. The balancer is positioned by a key located in the front of the crankshaft. Refer to «Crankshaft Balancer Removal»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-1-of-3__crankshaft-balancer-removal) .
New balancer onto an existing engine: Install the same size balance weights into the new balancer in the same location as the old balancer. Refer to «Crankshaft Balancer Cleaning and Inspection»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-1-of-3__crankshaft-balancer-cleaning-and-inspection) .

Engine Flywheel

For RPO-LSA manual transmission applications, the flywheel, clutch disc, and pressure plate are each individually balanced components and the clutch and pressure plate are available only as a kit. The pressure plate mounts, or locates, onto the flywheel dowel pins in the flywheel. If the pressure plate is not aligned properly onto the dowel pins and tightened down, the pins may bend and the plate may be incorrectly positioned, which will affect component balance. Refer to «Engine Flywheel Removal»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-1-of-3) .
Existing flywheel, clutch, and pressure plate onto the existing engine: Pressure plate position to flywheel must be marked prior to removal and installed to the original position. Flywheel position to crankshaft must also be marked prior to removal and installed to the original position. Refer to «Engine Flywheel Removal»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-1-of-3) .
Existing flywheel, clutch, and pressure plate onto a new engine: Pressure plate position to flywheel must be marked prior to removal and installed to the original position. Flywheel position to crankshaft must be marked prior to removal and installed to the similar position on the new engine. Do not remove balance weights from flywheel, if applicable.
New flywheel onto an existing engine: Install the same size balance weights into the new flywheel in the same location as the old flywheel. Install the new flywheel to a similar position on the new engine.
New flywheel, clutch, and pressure plate onto a new engine: Do not install balance weights.

Special Tools

J 35667-A Cylinder Head Leakdown Tester, or equivalent

Note. A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate one or more of the following conditions: Worn or burnt valves Broken valve springs Stuck valve lifters Incorrect valve lash 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»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-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 J 35667-A , or equivalent.
Apply shop air pressure to the J 35667-A 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 noise at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage noise at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage noise 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

Checks	Causes
Excessive oil consumption, not due to leaks, is the use of 1 L (1 qt) or more of engine oil within 3 200 kilometers (2,000 miles).
Preliminary	The causes of excessive oil consumption may include the following conditions: External oil leaks Refer to Oil Leak Diagnosis . Incorrect oil level or improper reading of the oil level indicator With the vehicle on a level surface, run the engine for a few minutes. Allow adequate drain down time, 2-3 minutes, and inspect for the correct engine oil level. Improper oil viscosity Refer to the vehicle owners manual and use the recommended SAE grade and viscosity for the prevailing temperatures. Continuous high speed driving and/or severe usage Crankcase ventilation system restrictions or malfunctioning components Refer to Crankcase Ventilation System Inspection/Diagnosis . Worn valve guides and/or valve stems Worn or improperly installed valve stem oil seals Refer to Spark Plug Inspection . Piston rings broken, worn, or not seated properly Allow adequate time for the rings to seat. Replace worn piston rings, as necessary. Refer to Cylinder Leakage Test . Piston and rings improperly installed or not fitted to the cylinder bore Refer to Lower Engine Noise, Regardless of Engine Speed .

Checks

Causes

Excessive oil consumption, not due to leaks, is the use of 1 L (1 qt) or more of engine oil within 3 200 kilometers (2,000 miles).

Preliminary

The causes of excessive oil consumption may include the following conditions: External oil leaks Refer to Oil Leak Diagnosis . Incorrect oil level or improper reading of the oil level indicator With the vehicle on a level surface, run the engine for a few minutes. Allow adequate drain down time, 2-3 minutes, and inspect for the correct engine oil level. Improper oil viscosity Refer to the vehicle owners manual and use the recommended SAE grade and viscosity for the prevailing temperatures. Continuous high speed driving and/or severe usage Crankcase ventilation system restrictions or malfunctioning components Refer to Crankcase Ventilation System Inspection/Diagnosis . Worn valve guides and/or valve stems Worn or improperly installed valve stem oil seals Refer to Spark Plug Inspection . Piston rings broken, worn, or not seated properly Allow adequate time for the rings to seat. Replace worn piston rings, as necessary. Refer to Cylinder Leakage Test . Piston and rings improperly installed or not fitted to the cylinder bore Refer to Lower Engine Noise, Regardless of Engine Speed .

Oil Pressure Diagnosis and Testing

Special Tools

EN 47971: Oil Pressure Gauge Adapter
J 21867: Pressure Gauge For equivalent regional tools, refer to «Special Tools»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-special-tools-and-equipment) .

With the vehicle on a level surface, run the vehicle for a few minutes, allow adequate drain down time, 2-3 minutes, and measure the oil level.
If required, add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
Run the engine briefly, 10-15 seconds, 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: Oil diluted by water or glycol antifreeze Foamy oil
Remove the oil filter and install the EN 47971: adapter (1).
Install the J 21867: gauge (2), or equivalent to the EN 47971: adapter (1).
Run the engine and measure the engine oil pressure.
Compare the readings to «Engine Mechanical Specifications»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-specifications__engine-mechanical-specifications) .
If the engine oil pressure is below specifications, inspect the engine for 1 or more of the following conditions: Oil pump worn or dirty Refer to «Oil Pump Cleaning and Inspection (6.2L)»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-2-of-3__oil-pump-cleaning-and-inspection-62l) . Oil pump-to-engine block bolts loose Refer to «Oil Pump, Screen and Crankshaft Oil Deflector Installation (6.2L)»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-2-of-3__oil-pump-screen-and-crankshaft-oil) . Oil pump screen loose, plugged, or damaged Oil pump screen O-ring seal missing or damaged Malfunctioning oil pump pressure relief valve Excessive bearing clearance Cracked, porous, or restricted oil galleries Oil gallery plugs missing or incorrectly installed Refer to «Engine Block Plug Installation»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-off-vehicle-2-of-3__engine-block-plug-installation) . Broken valve lifters Repair, as necessary.
If the oil pressure reading on the J 21867: gauge, or equivalent, is within specifications, inspect for the following conditions: Plugged or incorrect oil filter and/or malfunctioning oil bypass valve The bypass valve is now internal to the oil filter. Malfunctioning oil pressure gauge or sensor Repair, as necessary.

Diagnostic Instructions

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Signal Performance
Engine Oil Level Sensor Signal	2	1	1
Engine Oil Level Sensor Ground		1
1. DIC message Engine Oil Level Low Always ON 2. DIC message Engine Oil Level Low Always OFF

Typical Scan Tool Data

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Ignition ON Parameter Normal Range: OK
Engine Oil Level Sensor/Switch Signal	OK	Low	OK
Engine Oil Level Ground		Low

Engine Oil Level Switch

Circuit/System Description

The engine oil level sensor/switch is a normally-closed with proper engine oil level. The switch opens when the engine oil level drops below a calibrated level. The engine control module (ECM) monitors the engine oil level signal circuit when the ignition is ON, and the engine is OFF. With the switch in the closed position, the ECM detects a low voltage signal circuit. With the switch in the open position, the ECM detects a high voltage on the signal circuit. When high voltage is detected on the signal circuit, the ECM will send a serial data message to the instrument panel cluster and a message is displayed on the driver information center.

The following information determines the message sent form the ECM to the instrument cluster. The Engine Oil Level Low message is displayed only after the ECM detects a high voltage on the signal circuit for three consecutive ignition cycles, followed by an ignition OFF event from 15 min to greater than 50 min, depending on the engine oil temperature.

The Engine Oil Level Low message is turned OFF when the ECM detects a low voltage on the signal circuit after an ignition OFF event for greater than 90 s, then followed by the ignition ON for less than 1 s.

Reference Information

Schematic Reference

«Engine Mechanical Schematics»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-wiring-schematics)
«Instrument Cluster Schematics»(/cadillac/cts/ii-2007-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)

Connector End View Reference

Component Connector End Views

Description and Operation

«Instrument Cluster Description and Operation»(/cadillac/cts/ii-2007-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)
«Indicator/Warning Message Description and Operation»(/cadillac/cts/ii-2007-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-gauges)

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

Verify proper engine oil level. Add oil as necessary.
Ignition ON, observe the scan tool Engine Oil Level parameter. The reading should be OK and change to Low when the oil level sensor/switch harness connector is disconnected.

Circuit/System Testing

Note. Verify proper engine oil level before continuing with diagnosis.

Ignition OFF, disconnect the harness connector at the B35C engine oil level sensor.
Ignition OFF for 90 s, test for less than 2 ohms between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
Ignition ON, verify the scan tool Engine Oil Level Warning parameter reads Low. If the Oil Level Warning parameter reads OK, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and the ground circuit terminal C. Verify the scan tool Engine Oil Level Warning parameter reads OK. If the Engine Oil Level parameter reads Low, test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
If all circuits test normal, test or replace the B35C engine oil level temperature sensor.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Engine Oil Level Sensor and/or Switch Replacement»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle)
«Engine Control Module Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for the ECM replacement, setup, and programming

Oil Leak Diagnosis

Step	Action	Yes	No
IMPORTANT: 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. 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 kilometers, 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, baby powder, foot powder, etc., to the suspected area. Operate the vehicle for several kilometers, 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 attention 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. Does the engine still leak oil?	Go to Step 1	System OK

IMPORTANT
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.

Crankcase Ventilation System Inspection/Diagnosis

Concern	Action
External oil leak	Inspect for any of the following conditions: Plugged positive crankcase ventilation (PCV) Plugged or kinked PCV hose(s) Damaged or incorrectly installed PCV or hose(s) Excessive crankcase pressure
Rough Idle	Inspect for any of the following conditions: Plugged PCV Plugged or kinked PCV hose(s) Leaking (damaged) PCV or hose(s)
Stalling or slow idle speed	Inspect for any of the following conditions: Plugged PCV Plugged or kinked PCV hose(s) Leaking (damaged) PCV or hose(s)
High idle speed	Inspect for a leaking (damaged) PCV or hose(s)
Sludge in the engine	Inspect for any of the following conditions: Plugged PCV Plugged or kinked PCV hose(s)

Diagnostic Aids

A chirping or squealing noise may be intermittent due to moisture on the drive belt(s) or the pulley(s). It may be necessary to spray a small amount of water on the drive belt(s) in order to duplicate the customers concern. If spraying water on the drive belt duplicates the symptom, cleaning the belt pulley(s) 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 incorrect 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 diagnostic trouble codes (DTCs) may set when the engine is operating with the drive belt(s) 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 pulley. Chirping may occur on cold damp start-ups and will subside once the vehicle reaches normal operating temperature. DEFINITION: The following items are indications of drive belt squealing: 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 whining: A high pitched continuous noise. The noise may be caused by an accessory drive component failed bearing.
1	Did you review the Symptoms-Engine Mechanical operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Engine Mechanical
2	Verify that there is a chirping, squealing or whining noise. Does the engine make the chirping, squealing or whining 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, squealing or whining 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 squealing or whining noise, proceed to step 13. Does 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 accessory brackets. Did you find any bent or cracked brackets?	Go to Step 9	Go to Step 10
9	Replace any bent or cracked accessory brackets. Did you complete the repair?	Go to Step 20	Go to Step 10
10	Inspect for incorrect, 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 incorrect 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 whining noise and the condition still exists, 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 correct 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(s). 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 being over charged, the power steering system being restricted or the incorrect fluid being used, 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, diagnostic trouble codes (DTCs) may set when the engine is operating with the drive belt(s) 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 a normal condition and acceptable. When the pilling is severe the drive belt does not have a smooth surface for proper operation.
9: Inspection of the fasteners can eliminate the possibility that the incorrect 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 Symptoms - Engine Mechanical 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(s). 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?	For rumbling diagnosis, go to Symptoms - Engine Mechanical . For vibration diagnosis, go to Vibration Analysis - Engine .	Go to Step 4
4	Inspect the drive belt(s) for wear, damage, separation, sections of missing ribs, and/or 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. Did you correct the condition?	Go to Step 8	Go to Step 7
7	Install a new drive belt. Did you complete the replacement?	Go to Step 8
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 any improper or missing fasteners. Did you complete the repair?	Go to Step 13
11	Inspect for a bent water pump shaft. Did you find and correct the condition?	Go to Step 13	Go to Step 12
12	Inspect for bent or cracked accessory 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 a result of pulley misalignment.

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

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

Excessive wear on a drive belt is usually caused by an incorrect installation or the incorrect 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 have occurred to the drive belt when the drive belt fell off. The drive belt may be 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 being 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 repair 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 may allow the drive belt to fall off.
7: Inspecting of the fasteners can eliminate the possibility that a incorrect bolt, nut, spacer, or washer was installed. Missing, loose, or an incorrect fastener 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 component 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 sit correctly on the pulleys. Wear at the outside ribs of the drive belt may be due to an incorrectly installed drive belt.
1	Did you review the Symptoms-Engine-Mechanical 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. Does the drive belt continue to fall off?	Go to Step 4	System OK
4	Inspect for pulley misalignment. 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 accessory 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 any improper or missing fasteners. Does the drive belt continue to fall off?	Go to Step 9	System OK
9	Inspect the drive belt tensioner for proper operation. Refer to Drive Belt Tensioner Diagnosis . Does the drive belt tensioner operate properly?	Go to Step 11	Go to Step 10
10	Replace the drive belt tensioner. Does the drive belt continue to fall off?	Go to Step 11	System OK
11	Inspect for failed drive belt idler and/or 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. 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 the drive belt for contact 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 belts. 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

CAUTION

Allowing the drive belt tensioner to snap into the free position may result in damage to the tensioner.

Note. When the engine is operating, the belt tensioner arm will move. Do not replace the belt tensioner because of movement in the belt tensioner arm.

Remove the drive belt. Refer to «Drive Belt Replacement - Accessory»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle) or «Air Conditioning Compressor Belt Replacement»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle) .
Position a hex-head socket on the belt tensioner pulley bolt.
Move the belt tensioner through its full travel. The movement should feel smooth. There should be no binding. The belt tensioner should return freely.
If any binding is observed, replace the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement - Accessory»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle)
Install the drive belt. Refer to «Drive Belt Replacement - Accessory»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle) or «Air Conditioning Compressor Belt Replacement»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-repair-instructions-on-vehicle) .

Engine Mechanical - 6.2l - Diagnostic Information and Procedures Cadillac CTS II

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 (6.2L)

Supercharger Noise Diagnosis

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

Engine Compression Test

Engine Balancing

Special Tools

Oil Consumption Diagnosis

Oil Pressure Diagnosis and Testing

Diagnostic Instructions

Diagnostic Fault Information

Typical Scan Tool Data

Circuit/System Description

Reference Information

Circuit/System Verification

Circuit/System Testing

Repair Procedures

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis

Diagnostic Aids

Test Description

Drive Belt Tensioner Diagnosis

More articles — Engine

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