Symptom Table - NVH

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: NVH symptoms should be identified using the diagnostic tools that are available. For a list of these tools, an explanation of their uses and a glossary of common terms, refer to GLOSSARY OF TERMS . 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. If this is not the causal system for the symptom, refer back to NOISE, VIBRATION AND HARSHNESS (NVH) for the next likely system and continue diagnosis.

SYMPTOM TABLE - NVH

Condition	Possible Sources	Action
Drone type noise	Powertrain mount(s)	CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. TEST the system for normal operation after the repair.
Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold. Very low-frequency drumming is very rpm dependent	Engine vibration excites the body resonances inducing interior noise	CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. TEST the system for normal operation after the repair.
Engine drumming noise - accompanied by vibration	Powertrain mount(s)	CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. TEST the system for normal operation after the repair.
Rattle - occurs at idle or at light acceleration from a stop	Powertrain mount(s)	CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. For automatic transmission, Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. For manual transmission, REFER to MANUAL TRANSAXLE/TRANSMISSION . TEST the system for normal operation after the repair.
Whine/moan type noise - pitch increases or changes with vehicle speed	Powertrain mount(s)	CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. For automatic transmission, Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. For manual transmission, REFER to MANUAL TRANSAXLE/TRANSMISSION . TEST the system for normal operation after the repair.
Clunk - occurs when shifting from PARK or between REVERSE and DRIVE	Powertrain mounts	CHECK the powertrain/drivetrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. For automatic transmission, Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. For manual transmission, REFER to MANUAL TRANSAXLE/TRANSMISSION . TEST the system for normal operation after the repair.
-	Idle speed is too high	CHECK for the correct idle speed. TEST the system for normal operation after the repair.
Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately 4°C (40°F) or colder at the first start of the day	Accessory drive idler or tensioner pulley bearing is experiencing stick/slip between ball bearings and the bearing race	CARRY OUT the engine cold soak procedure. REFER to VEHICLE COLD SOAK PROCEDURE . PLACE the Engine EAR probe directly on the idler/tensioner center post or bolt to verify which bearing is making the noise. INSTALL new parts as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Accessory drive belt noise, squeal or chirping	Defective/worn or incorrect accessory drive belt Misaligned pulley(s) Pulley runout Damaged or worn accessory drive component or idler Fluid contamination of the accessory drive belt or pulleys Damaged or worn accessory drive belt tensioner Damaged pulley grooves	CARRY OUT the Engine Accessory Test. REFER to ENGINE ACCESSORY TEST . INSPECT components and INSTALL new parts as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Clunking noise	Coolant pump has excessive end play or imbalance	CHECK the coolant pump for excessive end play. INSPECT the coolant pump for imbalance with the drive belt off. INSTALL a new coolant pump as necessary. REFER to ENGINE COOLING or ENGINE COOLING for Hybrid . TEST the system for normal operation after the repair.
Whine or moaning noise	Air intake system	CHECK the air cleaner and ducts for correct fit. INSPECT the air intake system for leaks or damage. REPAIR as necessary. TEST the system for normal operation after the repair.
Whistling noise - normally accompanied with poor idle condition	Air intake system	CHECK the air intake ducts, air cleaner, Throttle Body (TB) and vacuum hoses for leaks and correct fit. REPAIR or ADJUST as necessary. TEST the system for normal operation after the repair.
Hissing noise - occurs during idle or high idle that is apparent with the hood open	Vacuum leak	USE the Engine EAR/Chassis EAR to locate the source. SCAN the air intake system from the inlet to each cylinder intake port. DISCARD the leaking parts, and INSTALL a new component. TEST the system for normal operation after the repair.
-	Vehicles with a plastic intake manifold	Acceptable condition. Some plastic intake manifolds exhibit this noise, which is the effect of the plastic manifold.
Grinding noise - occurs during engine cranking	Incorrect starter motor mounting	INSPECT the starter motor for correct mounting. REPAIR as necessary. REFER to INSPECTION AND VERIFICATION . TEST the system for normal operation after the repair.
-	Starter motor	CHECK the starter motor. INSTALL a new starter motor as necessary. REFER to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L) and REMOVAL AND INSTALLATION (3.5L) . TEST the system for normal operation after the repair.
-	Incorrect starter motor drive engagement	INSPECT the starter motor drive for wear or damage. INSTALL a new starter motor as necessary. REFER to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L) and REMOVAL AND INSTALLATION (3.5L) . TEST the system for normal operation after the repair. INSPECT the flywheel/flexplate for wear or damage. INSTALL a new flywheel/flexplate as necessary. Refer to INSTALLATION (2.5L), INSTALLATION (Hybrid), REMOVAL AND INSTALLATION (3.0L) and REMOVAL AND INSTALLATION (3.5L) for the procedure. TEST the system for normal operation after the repair.
Engine noise, front of engine - knocking noise from lower front of engine	Damaged or separated crankshaft pulley/damper	CHECK for obvious signs of damage or wobble during operation. INSTALL new as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Engine noise, front of engine - ticking, tapping or rattling noise from the front of the engine	Timing drive components	REMOVE the accessory drive belt. Refer to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L), REMOVAL (3.5L) and REMOVAL AND INSTALLATION (Hybrid) for the procedure. USE the Engine EAR to isolate the noise to the engine front cover. REMOVE the engine front cover and INSPECT the timing drive components. INSTALL new parts as necessary. Refer to INSTALLATION (2.5L), INSTALLATION (Hybrid), INSTALLATION (3.0L) and INSTALLATION for the procedure. TEST the system for normal operation after the repair.
Engine noise, upper end - ticking noise near the fuel rail and intake manifold	Fuel rail clip	CHECK for loose or damaged fuel rail clip(s). REPAIR as necessary.
-	Fuel injector	USE the Engine EAR to isolate the noisy injector(s). INSTALL a new injector(s) as necessary. Refer to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L), REMOVAL AND INSTALLATION (3.5L) and REMOVAL AND INSTALLATION (Hybrid) for the procedure. TEST the system for normal operation after the repair.
Engine noise, upper end - ticking, knocking or rattle noise that occurs during idle or high idle during the first cold start of the day and may disappear as the engine warms	Valve train noise (bled down lash adjuster)	CARRY OUT the Valve Train Analysis Component Test. INSTALL new parts as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Engine noise, upper end - occurs mostly with a warm engine at light/medium acceleration	Worn or damaged spark plugs	REMOVE the spark plugs. INSPECT and INSTALL new as necessary. Refer to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L) and REMOVAL AND INSTALLATION (3.5L) for the procedure. TEST the system for normal operation after the repair.
-	Carbon accumulation in combustion chamber	Bore scope the cylinder. ELIMINATE carbon buildup. TEST the system for normal operation after the repair.
Engine noise, upper end - rattling noise from the valve train. Worse when the engine is cold	Low oil level	CHECK the oil level. FILL as necessary.
-	Thin or diluted oil	INSPECT the oil for contamination. If the oil is contaminated, CHECK for the source. REPAIR as necessary. CHANGE the oil and filter.
-	Low oil pressure	CARRY OUT an oil pressure test. If not within specifications, REMOVE the engine oil pan. Refer to REMOVAL (2.5L), REMOVAL (Hybrid), REMOVAL (3.0L) and REMOVAL (3.5L) for the procedure. INSPECT for a blocked oil pick up tube.
-	Worn valve train components	CARRY OUT the Valve Train Analysis Component Test. INSTALL new parts as necessary. TEST the system for normal operation after the repair.
-	Worn valve guides	CARRY OUT the Valve Guide Inner Diameter procedure.
-	Excessive runout of the valve seats on the valve face	CARRY OUT the Valve Seat Inspection procedure.
Engine noise, upper end - pinging noise	Gasoline octane too low	VERIFY with customer the type of gasoline used. CORRECT as necessary. TEST the system for normal operation after the repair.
-	Knock Sensor (KS) operation	CHECK the KS . INSTALL a new KS as necessary. Refer to appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
-	Incorrect spark timing	CHECK the spark timing. REPAIR as necessary. TEST the system for normal operation after the repair.
-	High operating temperature	INSPECT the cooling system for leaks. CHECK the coolant level. REFILL as necessary. CHECK the coolant for the correct mix ratio. DRAIN and REFILL as needed. VERIFY the engine operating temperature is within specifications. REPAIR as necessary. TEST the system for normal operation after the repair.
-	Spark plug	CHECK the spark plugs. REPAIR or INSTALL new spark plugs as necessary. TEST the system for normal operation after the repair.
-	Catalytic converter	COMPARE with a similar vehicle for what is acceptable noise.
Engine noise, lower end - ticking or knocking noise near the oil filter adapter	Oil pump	USE the Engine EAR to verify the oil pump as the source of the noise at low rpm. REPAIR as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Engine noise, lower end - light knocking noise, also described as piston slap. Noise is most noticeable when the engine is cold with light to medium acceleration. The noise disappears as the engine warms	Excessive clearance between the piston and the cylinder wall	CARRY OUT the Piston To Cylinder Bore Clearance procedure. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
Engine noise, lower end - light double knock or sharp rap sound. Occurs mostly with a warm engine at idle or low speeds in drive. Increases in relation to engine load. Associated with a poor lubrication history	Excessive clearance between the piston and the piston pin	CARRY OUT the Piston Pin Bore Diameter procedure.
-	Excessive clearance between the piston and the connecting rod	CARRY OUT the Connecting Rod-to-Piston Clearance procedure.
Engine noise, lower end - light knocking noise. The noise is most noticeable when the engine is warm. The noise tends to decrease when the vehicle is coasting or in NEUTRAL	Excessive clearance between the connecting rod bearings and the crankshaft	CARRY OUT the Connecting Rod Bearing Journal-to-Bearing Clearance procedure.
Engine noise, lower end - Deep knocking noise. The noise is most noticeable when the engine is warm, at lower rpm and under a light load and then at float	Worn or damaged crankshaft main bearings	CARRY OUT the Crankshaft Main Bearing Journal-to-Bearing Clearance procedure.
Engine noise, rear of engine - knocking noise at rear of engine	Damaged flywheel/flexplate	CARRY OUT the Flywheel Inspection or Flexplate Inspection procedure.
Engine vibration - vibration felt at all times	Excessive engine pulley runout	CARRY OUT the Engine Accessory Test. REFER to ENGINE ACCESSORY TEST . INSTALL a new engine pulley as necessary. TEST the system for normal operation after the repair.
-	Damaged or worn accessory component	CARRY OUT the Engine Accessory Test. REFER to ENGINE ACCESSORY TEST . REPAIR or INSTALL a new component as necessary. TEST the system for normal operation after the repair.
Engine vibration - at idle, a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/floorpan	Cylinder misfire	Using the scan tool, CARRY OUT the cylinder power balance and the relative compression test. REPAIR as necessary. Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. TEST the system for normal operation after the repair.
-	Engine or torque converter out of balance	VERIFY the torque converter to crankshaft pilot clearance is correct. REPAIR as necessary. RE-INDEX the torque converter on the flexplate by 180 degrees for a 4-bolt converter. Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. TEST the system for normal operation after the repair.
Engine vibration - is felt with increases and decreases in engine rpm	Powertrain mount(s)	CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to ENGINE (2.5L), ENGINE (Hybrid), ENGINE (3.0L) and ENGINE (3.5L) for the procedure. For automatic transmission, Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. For manual transmission, REFER to MANUAL TRANSAXLE/TRANSMISSION . TEST the system for normal operation after the repair.
-	Engine or transmission grounded to chassis	INSPECT the powertrain/drivetrain for correct clearances. REPAIR as necessary. TEST the system for normal operation after the repair.
Engine vibration - increases intensity as the engine rpm is increased	Engine out-of-balance	CARRY OUT the Neutral Engine Run-Up (NERU) Test. REFER to NEUTRAL ENGINE RUN-UP (NERU) TEST . ROTATE the torque converter 180 degrees for 4-bolt. INSPECT the torque converter pilot outer diameter-to-crankshaft pilot inner diameter. REPAIR as necessary. Refer to IN-VEHICLE REPAIR , AUTOMATIC TRANSAXLE/TRANSMISSION - AISIN AW21 and AUTOMATIC TRANSAXLE/TRANSMISSION - ELECTRONICALLY CONTROLLED CONTINUOUSLY VARIABLE TRANSMISSION (ECVT) for the procedure. TEST the system for normal operation after the repair.
Engine vibration - mostly at coast/neutral coast. Condition improves with vehicle acceleration	Combustion instability	CHECK the ignition system. INSTALL new components as necessary. Refer to ENGINE IGNITION - 2.5L , ENGINE IGNITION - 3.0L (4V) and ENGINE IGNITION - 3.5L for the procedure. TEST the system for normal operation after the repair.
Engine vibration or shudder - occurs with light to medium acceleration above 56 km/h (35 mph)	Worn or damaged spark plugs	INSPECT the spark plugs for cracks, high resistance or broken insulators. INSTALL a new spark plug(s) as necessary. Refer to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L) and REMOVAL AND INSTALLATION (3.5L) for the procedure. TEST the system for normal operation after the repair.
-	Plugged fuel injector	REPAIR or INSTALL a new injector as necessary. Refer to REMOVAL AND INSTALLATION (2.5L), REMOVAL AND INSTALLATION (3.0L), REMOVAL AND INSTALLATION (3.5L) and REMOVAL AND INSTALLATION (Hybrid) for the procedure. TEST the system for normal operation after the repair.
-	Contaminated fuel	INSPECT the fuel for contamination. DRAIN the fuel system and refill. TEST the system for normal operation after the repair.