Symptom Chart - Engine NVH

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

Condition	Possible Sources	Action
NOTE: Engine 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 Noise, Vibration and Harshness . 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 for the next likely system and continue diagnosis.
Drone type noise	Powertrain mount(s)	CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure.
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.
Engine drumming noise - accompanied by vibration	Powertrain mount(s)	CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure.
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 the appropriate Engine article for the procedure. For automatic transmission, Refer to the appropriate Automatic Transmission article for the procedure.
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 the appropriate Engine article for the procedure. For automatic transmission, Refer to the appropriate Automatic Transmission article for the procedure.
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 the appropriate Engine article for the procedure. For automatic transmission, Refer to the appropriate Automatic Transmission article for the procedure.
Idle speed is too high		CHECK for the correct idle speed. REFER to Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
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 Noise, Vibration and Harshness . PLACE the EngineEAR 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 Accessory Drive .
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 Noise, Vibration and Harshness . INSPECT components and INSTALL new parts as necessary. REFER to Accessory Drive .
Pop noise - happens approximately 30 seconds after cold start up	Turbocharger bypass valve	Acceptable condition. The turbocharger bypass valve closes approximately 30 seconds after cold start up.
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 .
Whine/hum - occurs when unlocking the vehicle or opening the door with the engine off Gasoline Turbocharged Direct Injection (GTDI) only	Fuel pump module	Acceptable condition. Fuel pump module turns on before engine starts to prime the fuel system.
Whine or moaning noise	Air intake system	CHECK the ACL and ducts for correct fit. INSPECT the air intake system for leaks or damage. REPAIR as necessary. REFER to Intake Air Distribution and Filtering .
Whistling noise - normally accompanied with poor idle condition	Air intake system	CHECK the air intake ducts, ACL, Throttle Body (TB) and vacuum hoses for leaks and correct fit. REPAIR or ADJUST as necessary. Refer to the appropriate Engine article for the procedure.
Turbocharger intake tube assembly leaking		REPAIR or INSTALL a new tube as necessary. TEST the system for normal operation after the repair.
Loose connections or damage to air intake hoses and tubes		TIGHTEN hose clamps. INSPECT for damage and REPAIR as necessary. TEST the system for normal operation after the repair.
Air leaks at turbine housing, blown joints or damaged exhaust		INSPECT for leaks. Leaks can usually be detected audibility or visually, by discoloration caused by escaping hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair.
Carbon build up in the turbine housing		INSPECT the turbocharger. REFER to the Check for Free Rotation - Off Vehicle. REFER to Fuel Charging and Controls - Turbocharger, 3.5L GTDI . TEST the system for normal operation after the repair.
Turbocharger imbalance due to foreign object/damage		REPAIR as necessary. TEST the system for normal operation after the repair.
Turbine bearing failure		INSPECT the turbocharger. REFER to the Check for Free Rotation - Off Vehicle. REFER to Fuel Charging and Controls - Turbocharger, 3.5L GTDI . TEST the system for normal operation after the repair.
Inoperative turbocharger bypass valve		REFER to Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
Whine or air rush type noise	Turbocharger	Acceptable condition. Some whine or air noise is common.
Chrip or whoosh sound	Turbocharger bypass valve	CHECK the turbocharger bypass valve. REPAIR 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 noise	USE the EngineEAR 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.
Vehicles with a plastic intake manifold		Acceptable condition. Some plastic 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 the appropriate Engine article for the procedure.
Starter motor		CHECK the starter motor. INSTALL a new starter motor as necessary. Refer to the appropriate Engine article for the procedure.
Incorrect starter motor drive engagement		INSPECT the starter motor drive for wear or damage. INSTALL a new starter motor as necessary. Refer to the appropriate Engine article for the procedure. INSPECT the flywheel/flexplate for wear or damage. INSTALL a new flywheel/flexplate as necessary. Refer to the appropriate Engine article for the procedure.
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 the appropriate Engine article for the procedure.
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 the appropriate Engine article for the procedure. USE the EngineEAR 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 the appropriate Engine article for the procedure.
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 EngineEAR to isolate the noisy injector(s). INSTALL new injector(s) as necessary. Refer to the appropriate Engine article for the procedure.
Fuel injection pump (GTDI only)		This is a normal engine noise that can be verified by listening to another vehicle. If noise is excessive, REPAIR as necessary. 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	CARRY OUT the Valve Train Analysis Component Test in this article. INSTALL new parts as necessary. Refer to the appropriate Engine article for the procedure.
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 the appropriate Engine article for the procedure.
Carbon accumulation in combustion chamber		INSPECT the cylinder using a Bore scope. ELIMINATE carbon buildup.
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. TEST the system for normal operation after the repair.
Low oil pressure		CARRY OUT the Oil Pressure Test in this article. If not within specifications, remove the oil pan. Refer to the appropriate Engine article for the procedure. INSPECT for a blocked oil pick up tube. TEST the system for normal operation after the repair.
Worn valve train components		CARRY OUT the Valve Train Analysis Component Test in this article. INSTALL new parts as necessary. Refer to the appropriate Engine article for the procedure.
Worn valve guides		CARRY OUT the Valve Guide Inner Diameter procedure.
Excessive runout of the valve seats on the valve face		INSPECT for abnormalities on the valve face and valve seat. INSTALL a new cylinder head assembly If abnormalities are found.
Engine noise, upper end - pinging noise	Gasoline octane too low	VERIFY with customer the type of gasoline used. CORRECT as necessary.
Knock Sensor (KS) operation		CHECK the KS. INSTALL a new KS as necessary. Refer to the appropriate Engine article for the procedure.
Incorrect spark timing		REFER to the Engine Controls - Symptom Charts (Except Diesel & Hybrid) .
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. Refer to the appropriate Engine article for the procedure.
Spark plug		CHECK the spark plugs. REPAIR or INSTALL new spark plugs as necessary. Refer to the appropriate Engine article for the procedure.
Catalytic converter		Acceptable noise.
Engine noise, upper end - knocking or ticking noise, occurs mostly with a warm engine at idle	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.
Damaged or incorrect oil filter		INSPECT the oil filter. INSTALL a new oil filter as necessary.
Low oil pressure		CARRY OUT the oil pressure test in this article. If not within specifications, remove the oil pan. Refer to the appropriate Engine article for the procedure. INSPECT for a blocked oil pick up tube. TEST the system for normal operation after the repair.
Engine noise, lower end - ticking or knocking noise near the oil filter adapter	Oil pump	USE the EngineEAR to verify the oil pump as the source of the noise at low rpm. REPAIR as necessary. Refer to the appropriate Engine article for the procedure.
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 Diameter procedure. Refer to Piston Diameter . Measure the cylinder bore diameter. Subtract the piston diameter from the cylinder bore diameter to find the piston-to-cylinder bore clearance. Refer to Engine 3.5L GTDI for specifications.
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	MEASURE the piston pin bore and piston pin in 2 directions on each side. Refer to Engine 3.5L GTDI for specifications.
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	INSPECT the flywheel/flexplate for wear or damage. Install a new flywheel/flexplate as necessary. Refer to the appropriate Engine article for the procedure. TEST the system for normal operation after the repair.
Engine vibration - vibration felt at all times	Excessive crankshaft pulley runout	CARRY OUT the Engine Accessory Test. INSTALL a new crankshaft pulley as necessary. Refer to the appropriate Engine article for the procedure.
Damaged or worn accessory component		CARRY OUT the Engine Accessory Test. REPAIR or INSTALL a new component as necessary.
Engine vibration - at idle, a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/floorpan	Cylinder misfire	CARRY OUT the cylinder power balance and the relative compression test using the scan tool. REPAIR as necessary. Refer to the appropriate Engine article for the procedure.
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 120 degrees for a 3-bolt converter or 180 degrees for a 4-bolt converter. Refer to the appropriate Automatic Transmission article for the procedure.
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 the appropriate Engine article for the procedure. For automatic transmission, Refer to the appropriate Automatic Transmission article for the procedure.
Engine or transmission contacting the chassis		INSPECT the powertrain/drivetrain for correct clearances. REPAIR as necessary.
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 Noise, Vibration and Harshness . ROTATE the torque converter, 120 degrees for 3-bolt or 180 degrees for 4-bolt. INSPECT the torque converter pilot outer diameter to crankshaft pilot inner diameter. REPAIR as necessary. Refer to the appropriate Automatic Transmission article for the procedure.
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 the appropriate Engine article for the procedure.
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 the appropriate Engine article for the procedure.
Plugged fuel injector		INSTALL a new fuel injector as necessary. Refer to the appropriate Engine article for the procedure.
Contaminated fuel		INSPECT the fuel for contamination. DRAIN the fuel system and refill.