Pinpoint Test F: Engine Noise

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) .

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) .

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 .

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

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

Is the noise of concern present in the like vehicle? 

• Ignition OFF.

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

Is any mechanical damage present? 

• Check the engine oil level.

Is the engine oil level OK? 

• Check the engine oil for contamination.

Is the engine oil free of contamination? 

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

Is the correct engine oil used based on the vehicle service history? 

• Ignition ON.

• Carry out the PCMKOEO and KOER self-tests.

Are any Diagnostic Trouble Codes (DTCs) present? 

• Check the engine for an overheating condition.

Is an engine overheat condition present? 

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

Is any concern with the coolant pump present? 

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

Is a vacuum leak present? 

• 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.

Is any concern discovered with the air intake system? 

• Inspect the ignition system. Inspect the spark plugs for normal burning. REFER to: Spark Plug Inspection 

Is any concern found with the ignition system? 

• Inspect the accessory drive system.

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

Is any concern discovered with the accessory drive system? 

• Inspect the fuel injection system. REFER to the Diagnosis and Testing procedures in the appropriate fuel charging and controls and the appropriate fuel tank and lines article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is any concern discovered with the fuel injection system? 

• Inspect the starter motor for damage and correct installation. REFER to the Diagnosis and Testing procedure in the appropriate starting system article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is any concern discovered with the starter motor? 

• Inspect the powertrain mounts for damage.

Is any concern discovered with the powertrain mounts? 

• Inspect the exhaust system for damage. REFER to the Diagnosis and Testing procedure in the appropriate exhaust system article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is exhaust system the cause of the noise? 

• Check the turbocharger(s) for excessive noise. Compare the noise to another vehicle similarly equipped. REFER to the appropriate fuel charging and controls article turbocharger Diagnosis and Testing procedure for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Are the turbocharger(s) the cause of the noise? 

• Check the engine oil pressure. REFER to: Oil Pressure Test 

  Compare the engine oil pressure gauge to the engine oil pressure specifications in the appropriate Engine article specifications procedure of the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is the engine oil pressure within specification? 

• Using EngineEAR/ChassisEAR, stethoscope and accelerometers along with the VCMM, locate the engine noise. REFER to: Engine Noise Identification and Location 

Is the noise coming from the engine? 

• 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.

Is damage found to the flexplate, flywheel or clutch, are the torque converter, flexplate or flywheel fasteners loose or does the noise seem to be coming from between the engine and transmission? 

• 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.

Is damage found to the timing drive components? 

• 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.

Is damage found to the valve train? 

• Perform the valve train analysis. REFER to: Valve Train Analysis - 2.0L EcoBoost (177kW/240PS) - MI4/2.5L Duratec - Hybrid (121kW/164PS) (BG) 

  Compare the camshaft lift to the specifications in the appropriate Engine article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is the camshaft lift and valve clearance within specifications? 

• 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 . REFER to: Valve Guide Inner Diameter 

  Compare the measurement to the valve stem-to-guide clearance specification in the appropriate engine article specifications for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Are the valve clearances within specifications? 

• 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.

Is damage or excessive wear found on the balance shaft assembly or the bearings? 

• 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.

Is the engine oil pump damaged? 

• 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 

  Compare the connecting rod bearing journal clearance to the connecting rod bearing journal clearance specification in the specifications procedure for the appropriate Engine article of the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Are the connecting rod bearing journal clearances within specifications? 

• 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 

  Compare the crankshaft main bearing journal clearance to the crankshaft main bearing journal clearance specification in the specifications procedure for the appropriate Engine article of the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Are the crankshaft main bearing journal clearances within specifications? 

• 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 . Check the piston ring end gap. REFER to: Piston Ring End Gap . Measure the cylinder bore taper. REFER to: Cylinder Bore Taper . . Measure the piston diameter. REFER to: Piston Diameter 

  Calculate the piston-to-cylinder bore clearance and compare the specification to the specification procedure in the appropriate Engine article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.

Is the piston-to-cylinder wall clearance within specification?