Lincoln Corsair: Engine System - General Information / Diagnosis and Testing - Engine

Possible Sources

• Gasket
• Seal
• Blocked or restricted turbocharger oil drain pipe
• Damaged or collapsed air intake hoses and tubes
• Turbocharger oil seals
• Inoperative PCV system
• Incorrect engine oil
• Worn valve stem seal
• Worn valve stem or valve guide
• Sticking piston ring
• Worn piston ring groove
• Damaged oil control ring
• Worn piston or cylinder

• Carry out the engine oil consumption test
  REFER to: Oil Consumption Test (303-00 Engine System - General Information, General Procedures).
  

• Ignition ON.

• Carry out the PCM KOEO and KOER self-tests.

• Ignition OFF.

• Inspect the engine for signs of engine oil leaks.
  REFER to: Oil Leak Inspection (303-00 Engine System - General Information, General Procedures).
  

• Check the vehicle service history and make sure the correct engine oil used is documented.

• Inspect the air intake system and make sure all of the hoses and tubes are securely connected and free of damage.

• Inspect the PCV system and make sure all of the hoses and tubes are securely connected, free of damage and the PCV valve operates correctly.

• Check for engine oil in the cooling system.

• Inspect the engine oil cooler and seals for damage.

• Inspect the turbocharger(s) for indication of an oil seal leaking in to the air intake or exhaust system. REFER to the Diagnosis and Testing procedure in the 303-04 Turbocharger section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Inspect the spark plugs for signs of oil fouling.
  REFER to: Spark Plug Inspection (303-00 Engine System - General Information, General Procedures).
  Using a bore scope, inspect the pistons for oil deposits.

• Remove the cylinder head(s). Inspect the cylinder head gasket, cylinder head and cylinder block for damage.
  REFER to: Cylinder Block Distortion (303-00 Engine System - General Information, General Procedures).
  and REFER to: Cylinder Head Distortion (303-00 Engine System - General Information, General Procedures).
  

• Remove the cylinder head(s). Remove the valves from the cylinder heads and inspect the valve stem seals for damage, excessive wear and proper sealing.

• Inspect the valves for excessive oil or carbon build up. Inspect the valves, valve stems and valve guides for damage.
  REFER to: Valve Guide Inner Diameter (303-00 Engine System - General Information, General Procedures).
  REFER to: Valve Stem Diameter (303-00 Engine System - General Information, General Procedures).
  

• Disassemble the engine. Check the pistons and piston rings for excessive carbon build up. Check the pistons, piston rings and cylinder bores for excessive wear or damage.
  REFER to: Piston Inspection (303-00 Engine System - General Information, General Procedures).
  REFER to: Piston Ring End Gap (303-00 Engine System - General Information, General Procedures).
  REFER to: Cylinder Bore Taper (303-00 Engine System - General Information, General Procedures).
  

Possible Sources

• Seal
• Coolant hose
• Engine oil cooler
• Coolant pump
• Radiator
• Heater core
• Engine front cover
• EGR cooler
• Head gasket
• Cylinder head
• Cylinder block

Visual Inspection and Pre-checks

• Check for engine coolant leaks around sealed areas, such as the coolant pump, intake manifold and cylinder heads.
• Check the coolant hoses and tubes for damage.
• Check the coolant hose and tube connections and make sure they are securely connected.

NOTE: A sweet odor accompanying white smoke is not considered normal and is indicative of coolant in the exhaust.

• Ignition OFF.

• Inspect the engine and cooling system for signs of coolant leaking externally. REFER to the Diagnosis and Testing procedure in the 303-03 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Start the engine.

• NOTE: Coolant intrusion in to the cylinders will cause white smoke from the exhaust. Allow the engine to reach normal operating temperature. Inspect the exhaust for excessive white smoke.

• Ignition OFF.

• Remove and inspect the engine oil level indicator for signs of coolant in the oil.

• Inspect the engine oil cooler and seals for damage.

• Remove the engine front cover. Refer to the 303-01 engine front cover procedure for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.Check the front cover seals for damage and signs of coolant passing in to the engine oil.

• Remove the spark plugs. Refer the 303-07 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure. Inspect the spark plugs for signs of coolant intrusion.
  REFER to: Spark Plug Inspection (303-00 Engine System - General Information, General Procedures).
  Using a bore scope, inspect the cylinders and pistons for signs of coolant intrusion.

• NOTE: On engines equipped with an EGR cooling system, the hot exhaust gases are cooled by a cooler that uses coolant. It is possible for coolant to be lost to EGR system if the cooler is damaged. Inspect the EGR system for damage resulting in coolant intrusion. If necessary, REMOVE any EGR components for access to inspect the components for signs of coolant intrusion. Refer to the 303-08 section for the engine being diagnosed.

• Ignition OFF.

• Perform a compression test and cylinder leakage test. Check the test results for signs of a damaged head gasket or cylinder head sealing surfaces. Check the coolant for bubbles caused by air entering the cooling system from compression.
  REFER to: Compression and Cylinder Leakage Test (303-00 Engine System - General Information, General Procedures).
  

• Remove the cylinder heads. Refer to the 303-01 cylinder head procedure(s) for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure. Inspect the head gasket(s) for signs of damage or failure. Inspect the cylinder block and cylinder head(s) for damage.
  REFER to: Cylinder Block Distortion (303-00 Engine System - General Information, General Procedures).
  and REFER to: Cylinder Head Distortion (303-00 Engine System - General Information, General Procedures).
  

Possible Sources

• Condensation build up in exhaust
• Air cleaner element
• Fuel injection system
• Coolant intrusion to combustion chamber
• Excessive engine oil consumption

NOTE: Black soot near the exhaust tailpipe area is a normal condition created from rich air/fuel mixture under low load conditions.

NOTE: The higher the ambient temperature, the less likely water vapor is seen exiting the tailpipe during engine startup and engine warm-up. The colder the ambient temperature, the more likely water vapor is seen exiting the exhaust tailpipe during engine startup and engine warm-up. This is a normal operating condition.

NOTE: A sweet odor accompanying white smoke is not considered normal and is indicative of coolant in the exhaust.

NOTE: Make sure the engine is at ambient shop temperature prior to starting this test.

NOTE: If a sweet odor accompanies white smoke, proceed to step C2.

• Start the engine while observing the exhaust exiting the tailpipe and allow the engine to reach normal operating temperature.

• Ignition ON.

• Carry out the PCM KOEO and KOER self-tests.

• Check the air cleaner element.

• Check the fuel system for normal operation. REFER to the Diagnosis and Testing procedures in 303-04 Fuel Charging and Controls for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

Possible Sources

• Accessory drive concern
• Air intake system concern
• Brake system concern
• Cooling system concern
• Exhaust system concern
• Fuel system concern
• Ignition system concern
• Throttle body concern
• Lubrication system concern
• Turbocharger concern
• Turbocharger bypass valve concern
• Transmission system concern
• Clutch system concern
• Intake or exhaust valve concern
• Valve spring concern
• Valve tappet
• Camshaft
• Cylinder head gasket
• Cylinder head
• Piston or piston ring concern

Visual Inspection and Pre-checks

• Verify the accessory drive operates correctly.
• Verify the brake system operates correctly.
• Verify the fuel system is free of leaks.
• Verify the throttle body is free of damage.
• Verify the engine oil level is OK.
• Verify the transmission operates correctly.
• Verify the clutch system (if equipped) operates correctly.

NOTE: This pinpoint test presumes all of the visual inspections and pre-checks have been completed.

• Ignition ON.

• Carry out the PCM KOEO and KOER self-tests.

• Check the following Parameter Identifications (PIDs) for simultaneous brake pedal and accelerator pedal operation:

  • Access the  PCM  and monitor the  BRKOVR_ACTION  PID

  • Access the  PCM  and monitor the  BRKOVRD_POSS  PID

  • Access the  PCM  and monitor the  DIST_BRKOVRD (km)  PID

• Inspect the air cleaner.

• Check the air intake system, air cleaner and CAC components, ducts, pipes and hoses. Check that all components are installed correctly and tight. Check that all components are aligned correctly. Check for damage that could cause an air-intake leak resulting in loss of boost. For additional information, refer to the 303-12 Intake Air Distribution and Filtering section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

NOTE: It may be necessary to use a smoke machine to locate any vacuum leaks.

• Check for vacuum leaks.

• If necessary, perform the intake manifold vacuum test.
  REFER to: Intake Manifold Vacuum Test (303-00 Engine System - General Information, General Procedures).
  Use the intake manifold vacuum test procedure to help identify possible sources of the condition.

NOTE: It may be necessary to use a smoke machine to locate any vacuum leaks.

• Check for intake manifold vacuum leaks or damage.

• Check the exhaust system for restrictions or damage. Refer to the 309-00 Exhaust System section for the engine being diagnosed. Refer to the appropriate section in Group 309 for the procedure.

• Inspect the engine and cooling system for overheating concerns. Refer to the Diagnosis and Testing procedure in the 303-03 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Inspect the ignition system. Refer to the Diagnosis and Testing procedure in the 303-07 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Ignition OFF.

• Remove the spark plugs. Refer the 303-07 section for the engine being diagnosed.Refer to the appropriate section in Group 303 for the procedure. Inspect the spark plugs for signs of inefficient combustion.
  REFER to: Spark Plug Inspection (303-00 Engine System - General Information, General Procedures).
  Use the spark plug inspection procedure to help identify possible sources of the condition.

• Perform a compression test and cylinder leakage test. Check the test results for signs of a damaged head gasket cylinder head sealing surfaces or loss of compression or blow by. Check the coolant for bubbles caused by air entering the cooling system from compression.
  REFER to: Compression and Cylinder Leakage Test (303-00 Engine System - General Information, General Procedures).
  

• Inspect the fuel system. Refer to the Diagnosis and Testing procedure in the 303-04 Fuel or 310-00 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure. Refer to the appropriate section in Group 310 for the procedure.

• Check the fuel pressure. Refer to the fuel system pressure check procedure in the 310-00 section for the engine being diagnosed. Refer to the appropriate section in Group 310 for the procedure. Compare the fuel pressure to the specification listed in the 310-00 specification procedure.

• Draw a sample of the fuel. Check the fuel for contamination.

• Check the engine oil pressure.
  REFER to: Oil Pressure Test (303-00 Engine System - General Information, General Procedures).
  Compare the engine oil pressure gauge to the engine oil pressure specifications in the 303-01 specifications procedure of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Inspect the turbocharger(s) for damage that could cause loss of boost. REFER to the Diagnosis and Testing procedure in the 303-04 Turbocharge section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the engine front cover. Inspect the timing components for excessive wear or damage that could cause timing concerns. Check for a stretched timing chain or belt. Check for excessive wear on the timing guides. Check the tensioner plungers for over extension. Inspect the VCT unit(s) for damage or excessive wear.

• Remove the valve cover(s). Visually inspect the camshafts and valve train for obvious signs of excessive wear or damage. Check for broken valve springs, damaged valve retainers, missing or damaged valve keepers or bent valves.

• Perform the valve train analysis.
  REFER to: Valve Train Analysis (303-00 Engine System - General Information, General Procedures).
  . Compare the camshaft lift to the specifications in the 303-01 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the cylinder heads. Refer to the 303-01 cylinder head procedure(s) for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure. Inspect the head gasket(s) for signs of damage or failure. Inspect the cylinder block and cylinder head(s) for damage.
  REFER to: Cylinder Block Distortion (303-00 Engine System - General Information, General Procedures).
  and REFER to: Cylinder Head Distortion (303-00 Engine System - General Information, General Procedures).
  

• Remove the cylinder head(s). Remove the valves from the cylinder heads and inspect the valve stem seals for damage, excessive wear and proper sealing.

• Inspect the valves for excessive engine oil or carbon build up. Inspect the valve seat contact surface and valve seats for damage or wear. Inspect for a burnt or pitted sealing contact surface. Inspect for an even sealing contact surface around the valve and the valve seat. Inspect the valves, valve stems and valve guides for damage.
  REFER to: Valve Guide Inner Diameter (303-00 Engine System - General Information, General Procedures).
  REFER to: Valve Stem Diameter (303-00 Engine System - General Information, General Procedures).
  

• Disassemble the engine. Check the pistons and piston rings for signs of excessive blow by. Check for excessive carbon build up. Check the pistons, piston rings and cylinder bores for excessive wear or damage.
  REFER to: Piston Inspection (303-00 Engine System - General Information, General Procedures).
  REFER to: Piston Ring End Gap (303-00 Engine System - General Information, General Procedures).
  REFER to: Cylinder Bore Taper (303-00 Engine System - General Information, General Procedures).
  

Possible Sources

• Engine oil
• Engine oil filter housing
• Engine oil filter
• Engine oil pump
• Engine oil pressure control solenoid
• VCT unit(s)
• Engine oil pick-up tube plugged
• Excessive connecting rod bearing clearance
• Excessive crankshaft main bearing clearance

Visual Inspection and Pre-checks

• Verify the engine oil level is within specification.

NOTE: This step is only necessary for symptom based diagnostics. For DTC based diagnostics, proceed to the next step.

• Ignition ON.

• Carry out the PCM KOEO and KOER self-tests.

• Check the vehicle service history and make sure the correct oil used is documented.

• For the 2.7L and 3.0L Ecoboost engine, remove the oil filter housing. Inspect:
  • the oil filter housing for a plugged center stem.
  • the oil filter housing for a missing or damaged center stem.
  • for missing or damaged O-ring seal on the stem.

• For all other engines, remove the oil filter. Inspect:
  • the oil filter for being damaged.
  • the oil filter header for a damaged center stem.
  • for missing or damaged O-ring seal.

• Install the engine oil filter housing or engine oil filter.

• Check the engine oil pressure.
  REFER to: Oil Pressure Test (303-00 Engine System - General Information, General Procedures).
  Compare the engine oil pressure gauge to the engine oil pressure specifications in the 303-01 specifications procedure of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the engine oil pan. Refer to the Removal and Installation procedure in the 303-01 section. Refer to the appropriate section in Group 303 for the procedure. INSPECT for a blocked engine oil pick up tube.

• Inspect for a blocked engine oil pick up tube.

• Visually inspect the engine oil pan for signs of a mechanical damage or excessive wear, such as metal flakes settled at the bottom of the engine oil pan, pieces of metal or other debris from the timing components.

• Remove the engine oil pan. Remove the connecting rod caps and check the bearings for signs of excessive wear or damage. Check the connecting rod bearing journal clearance.
  REFER to: Connecting Rod Bearing Journal Clearance (303-00 Engine System - General Information, General Procedures).
  Compare the connecting rod bearing journal clearance to the connecting rod bearing journal clearance specification in the specifications procedure for the 303-01 section of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the crankshaft main bearing caps and check the bearings for signs of excessive wear or damage. Check the crankshaft main bearing clearance.
  REFER to: Crankshaft Main Bearing Journal Clearance (303-00 Engine System - General Information, General Procedures).
  Compare the crankshaft main bearing journal clearance to the crankshaft main bearing journal clearance specification in the specifications procedure for the 303-01 section of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

Normal Operation and Fault Conditions

Since it is possible that any one of multiple systems may be the cause of the symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system. NVH symptoms should be identified using the diagnostic tools and techniques that are available. For a list of these techniques, tools, an explanation of their uses and a glossary of common terms, REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).

In some cases, a noise may be a normal characteristic of that engine type. In other cases the noise may require further investigation. Comparing the noise to a similar year/model vehicle equipped with the same engine aids in determining if the noise is normal or abnormal.

Once a concern is identified as an abnormal engine noise, it is critical to determine the location of the specific noise. Use the EngineEAR/ChassisEAR or stethoscope (the noise is always louder closer to the noise source) to isolate the location of the noise to one of the following areas.

• Fuel injector(s)
• Upper end of engine
• Lower end of engine
• Front of engine
• Rear of engine

Fuel injector noise

A common source of an engine ticking noise can be related to the fuel injection pump (Ecoboost engine) or fuel injector(s). This is normal engine noise that can be verified by listening to another like vehicle. If the injector noise is excessive or irregular, use the EngineEAR/ChassisEAR or stethoscope to isolate the noise to a specific fuel injector.

Upper End Engine Noise

A common source of upper end engine noise (ticking, knocking or rattle) includes the camshaft(s) and valve train. Upper end engine noise can be determined using the EngineEAR/ChassisEAR or stethoscope on the valve cover bolts. If the noise is loudest from the valve cover bolts, the noise is within the upper end. The EngineEAR/ChassisEAR or stethoscope can be used to further isolate the noise to the specific cylinder bank and cylinder. Removal of the valve covers is required to pinpoint the source of the noise.

Lower End Engine Noise

A common source of lower end engine noise (ticking or knocking) includes the crankshaft, connecting rod(s) and bearings. Lower end noises can be determined by using the engine oil pan or lower cylinder block. If the noise is loudest from these areas, the noise is within the lower end. If an engine noise is isolated to the lower end, some disassembly of the engine may be required to inspect for damage or wear.

Front of Engine Noise

A common source of noise from the front of the engine (squeal, chirp, whine or hoot) is the FEAD components. To isolate FEAD noise, carry out the Engine Accessory Test, REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).

Some other noises from the front of the engine (ticking, tapping or rattle) may be internal to the engine. Use the EngineEAR/ChassisEAR or stethoscope on the engine front cover to determine if the noise is internal to the engine. Removal of the engine front cover may be necessary to inspect internal engine components.

Rear of Engine Noise

A common source of noise from the rear of the engine (knocking) is the flywheel/flexplate. Inspection of the flywheel/flexplate is necessary.

Some engines have timing drive components at the rear of the engine and may be the source of noise (ticking, knocking or rattle). Use the EngineEAR/ChassisEAR or stethoscope on the rear of the engine if the noise is suspected to be internal to the engine. Some disassembly of the engine may be required to inspect for damage or wear.

Turbocharger Noise (Ecoboost Engine)

A common source of noise is the turbocharger. Some whine or air rush noise is an acceptable condition.

To help locate the source of engine noise, REFER to: Engine Noise Identification and Location (303-00 Engine System - General Information, General Procedures).

Possible Sources

• Expanding/contracting materials
• Thin or diluted engine oil
• Low engine oil level
• Vacuum leak
• Cooling system concern
• Powertrain mount(s)
• Drivetrain
• Accessory drive system concern
• Air intake system concern
• Turbocharger bypass valve
• Turbocharger
• Engine or transmission interference to chassis or body
• Starter motor
• Fuel injector
• Fuel pump
• Fuel injection pump (direct injection engines only)
• Flywheel/flexplate
• Timing drive system concern
• Valve train component concern
• Cylinder head
• Balance shaft assembly
• Engine oil pump
• Lower end rotating assembly (connecting rods or crankshaft) concern
• Pistons/cylinder walls

NOTE: A metal pinging/clicking sound occurring while the engine is cooling down after reaching normal operating temperature is considered normal.

• Compare the noise concern to a like vehicle, similarly equipped.

• Ignition OFF.

• Visually inspect the powertrain components and all possible causes listed for obvious signs of mechanical damage.

• Check the engine oil level.

• Check the engine oil for contamination.

• Check the vehicle service history and make sure the correct engine oil used is documented.

• Ignition ON.

• Carry out the PCM KOEO and KOER self-tests.

• Check the engine for an overheating condition.

• Check the coolant pump for excessive end play. Inspect the coolant pump for imbalance with the drive belt off.

NOTE: A smoke machine may be used to identify the location of a vacuum leak.

• Inspect the vacuum hoses for leaks and check the engine for a vacuum leak.

NOTE: The turbocharger bypass valve closes approximately 30 seconds after cold start up creating a pop noise. This is a normal operating condition.

NOTE: A hissing noise on vehicles with a plastic intake manifold may occur during idle or high idle that is apparent with the hood open. This is a normal operating condition.

• Inspect the air intake system.

• Check the air intake ducts, air cleaner and throttle body for leaks and correct fit.

• If equipped, check the turbocharger/supercharger and CAC and tubes for leaks, correct alignment and damage.

• Inspect the ignition system. Inspect the spark plugs for normal burning.
  REFER to: Spark Plug Inspection (303-00 Engine System - General Information, General Procedures).
  

NOTE: The Engine Cold Soak and Engine Accessory Test procedures can be used to help identify a concern with the accessory drive. If a concern exists, place the EngineEAR probe directly on the idler/tensioner center post or bolt to verify which bearing is making the noise.

• Inspect the accessory drive system.

• If necessary, carry out the Engine Accessory Test.
  REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Diagnosis and Testing).
  

NOTE: The fuel pump module turns on before the engine starts to prime the fuel system. A whine or hum may be heard when unlocking the vehicle or opening the door with the engine off. This is a normal operating condition.

• Inspect the fuel injection system. REFER to the Diagnosis and Testing procedures in the 303-04 and 310-01 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Inspect the starter motor for damage and correct installation. REFER to the Diagnosis and Testing procedure in the 303-06 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Inspect the powertrain mounts for damage.

• Inspect the exhaust system for damage. REFER to the Diagnosis and Testing procedure in the 309-00 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Check the turbocharger(s) for excessive noise. Compare the noise to another vehicle similarly equipped. REFER to the 303-04 turbocharger Diagnosis and Testing procedure for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Check the engine oil pressure.
  REFER to: Oil Pressure Test (303-00 Engine System - General Information, General Procedures).
  Compare the engine oil pressure gauge to the engine oil pressure specifications in the 303-01 specifications procedure of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Using EngineEAR/ChassisEAR, stethoscope and accelerometers along with the VCMM , locate the engine noise.
  REFER to: Engine Noise Identification and Location (303-00 Engine System - General Information, General Procedures).
  

• If equipped, remove the torque converter nut/bolt access plug. If equipped, remove the inspection cover. If needed, remove the starter motor. Check if the torque converter nuts or bolts are loose. Visually inspect the flexplate or flywheel and clutch for damage. Using an assistant, rotate the crankshaft pulley by hand while inspecting the flexplate or flywheel and clutch and listening for unusual noises coming from between the engine and transmission. Check to be sure the flexplate or flywheel do not feel loose on the crankshaft. Restrict the movement of the flexplate or flywheel while an assistant turns the crankshaft by hand if needed to help identify a possible source of the noise.

• Remove the engine front cover. Inspect the timing components for excessive wear or damage. Inspect the engine front cover for contact marks from the timing chain or belt. Inspect the VCT unit(s) for damage or excessive wear.

• Remove the valve cover(s). Visually inspect the camshafts and valve train for obvious signs of excessive wear or damage. Check for broken valve springs, damaged valve retainers, missing or damaged valve keepers or bent valves.

• Perform the valve train analysis.
  REFER to: Valve Train Analysis (303-00 Engine System - General Information, General Procedures).
  . Compare the camshaft lift to the specifications in the 303-01 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the cylinder head(s). Remove the valves from the cylinder heads and inspect the valves and valve guides for excessive wear or damage.
  REFER to: Valve Stem Diameter (303-00 Engine System - General Information, General Procedures).
  REFER to: Valve Guide Inner Diameter (303-00 Engine System - General Information, General Procedures).
  Compare the measurement to the valve stem-to-guide clearance specification in 303-01 specifications for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• If equipped, remove the balance shaft assembly. Inspect the balance shaft assembly for excessive wear or damage. Check the bearing surfaces for excessive wear or damage.

• Remove the engine oil pump. Check the engine oil pump for damage or excessive wear. Check for cracks on the housing. Check for scoring or excessive clearance on the gearotor or internal moving parts.

• Remove the engine oil pan. Remove the connecting rod caps and check the bearings for signs of excessive wear or damage. Check the connecting rod bearing journal clearance.
  REFER to: Connecting Rod Bearing Journal Clearance (303-00 Engine System - General Information, General Procedures).
  Compare the connecting rod bearing journal clearance to the connecting rod bearing journal clearance specification in the specifications procedure for the 303-01 section of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the crankshaft main bearing caps and check the bearings for signs of excessive wear or damage. Check the crankshaft main bearing clearance.
  REFER to: Crankshaft Main Bearing Journal Clearance (303-00 Engine System - General Information, General Procedures).
  Compare the crankshaft main bearing journal clearance to the crankshaft main bearing journal clearance specification in the specifications procedure for the 303-01 section of the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.

• Remove the engine. Remove the piston and connecting rod assemblies from the engine. Inspect the pistons, piston rings and cylinder walls for signs of piston slap. Inspect the pistons.
  REFER to: Piston Inspection (303-00 Engine System - General Information, General Procedures).
  Check the piston ring end gap. REFER to: Piston Ring End Gap (303-00 Engine System - General Information, General Procedures).
  Measure the cylinder bore taper. REFER to: Cylinder Bore Taper (303-00 Engine System - General Information, General Procedures).
  . Measure the piston diameter. REFER to: Piston Diameter (303-00 Engine System - General Information, General Procedures).
  Calculate the piston-to-cylinder bore clearance and compare the specification to the specification procedure in the 303-01 section for the engine being diagnosed. Refer to the appropriate section in Group 303 for the procedure.