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- Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold. Very low-frequency drumming is very RPM dependent
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- Engine vibration excites the body resonances inducing interior noise
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- Engine drumming noise - accompanied by vibration
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- Rattle - occurs at idle or at light acceleration from a stop
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- Whine/moan type noise - pitch increases or changes with vehicle speed
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- Clunk - occurs when shifting from PARK or between REVERSE and DRIVE
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- CHECK for the correct idle speed. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately4° C (39° F) or colder at the first start of the day
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- Accessory drive idler or tensioner pulley bearing is experiencing stick/slip between ball bearings and the bearing race
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- Accessory drive belt noise, squeal or chirping
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- 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
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- Coolant pump has excessive end play or imbalance
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- Whistling noise - normally accompanied with poor idle condition
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- Hissing noise - occurs during idle or high idle that is apparent with the hood open
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- 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. Refer to REFER to INTAKE AIR SYSTEM COMPONENTS - EXPLODED VIEW
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- Vehicles with a plastic intake manifold
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- Acceptable condition. Some plastic manifolds exhibit this noise, which is the effect of the plastic manifold.
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- Grinding noise - occurs during engine cranking
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- Incorrect starter motor mounting
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- Incorrect starter motor drive engagement
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- INSPECT the flywheel/flexplate for wear or damage, refer to Flexplate Inspection . INSTALL a new flywheel/flexplate as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Engine noise, front of engine - knocking noise from lower front of engine
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- Damaged or separated crankshaft pulley/damper
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- CHECK for obvious signs of damage or wobble during operation. INSTALL new as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Engine noise, front of engine - ticking, tapping or rattling noise from the front of the engine
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- REMOVE the accessory drive belt. REFER to
FRONT END ACCESSORY DRIVE (FEAD) - EXPLODED VIEW
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- 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/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Engine noise, upper end - ticking noise near the fuel rail and intake manifold
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- CHECK for loose or damaged fuel rail clip(s), or fuel line clip/retainers. REPAIR as necessary.
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- USE the EngineEAR to isolate the noisy injector(s). INSTALL a new injector(s) as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedure. TEST the system for normal operation after the repair.
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- 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
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- CARRY OUT the Valve Train Analysis Component Test. REFER to Valve Train Analysis . INSTALL new parts as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Engine noise, upper end - occurs mostly with a warm engine at light/medium acceleration
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- Worn or damaged spark plugs
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- Carbon accumulation in combustion chamber
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- INSPECT the cylinder using a Bore scope. ELIMINATE carbon buildup.
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- Engine noise, upper end - rattling noise from the valve train. Worse when the engine is cold
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- CHECK the oil level. FILL as necessary.
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- Worn valve train components
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- CARRY OUT the Valve Train Analysis Component Test. REFER to Valve Train Analysis . INSTALL new parts as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- Excessive runout of the valve seats on the valve face
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- Engine noise, upper end - pinging noise
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- VERIFY with customer the type of gasoline used. CORRECT as necessary.
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- Knock Sensor (KS) operation
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- CHECK the spark timing. REPAIR as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures. TEST the system for normal operation after the repair.
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- High operating temperature
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- 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
ENGINE COOLING
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- Engine noise, upper end - knocking or ticking noise, occurs mostly with a warm engine at idle
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- CHECK the oil level. FILL as necessary.
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- INSPECT the oil for contamination. If the oil is contaminated, CHECK for the source. REPAIR as necessary. CHANGE the oil and filter.
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- Damaged or incorrect oil filter
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- INSPECT the oil filter. INSTALL a new oil filter as necessary.
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- Engine noise, lower end - ticking or knocking noise near the oil filter adapter
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- 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(s)
for the procedure. TEST the system for normal operation after the repair.
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- 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
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- Excessive clearance between the piston and the cylinder wall
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- 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
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- Excessive clearance between the piston and the piston pin
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- 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
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- Excessive clearance between the connecting rod bearings and the crankshaft
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- 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
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- Worn or damaged crankshaft main bearings
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- Engine noise, rear of engine - knocking noise at rear of engine
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- Damaged flywheel/flexplate
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- Engine vibration - vibration felt at all times
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- Excessive crankshaft pulley runout
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- Damaged or worn accessory component
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- Engine vibration - at idle, a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/floorpan
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- CARRY OUT the cylinder power balance and the relative compression test using the scan tool. REPAIR as necessary. Refer to the appropriate engine/performance service information article(s)
for the procedures.
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- Engine or torque converter out of balance
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- 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.
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- Engine vibration - is felt with increases and decreases in engine RPM
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- Engine or transmission contacting the chassis
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- INSPECT the powertrain/drivetrain for correct clearances. REPAIR as necessary.
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- Engine vibration - increases intensity as the engine RPM is increased
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- CARRY OUT the NERU Test. REFER to NEUTRAL ENGINE RUN-UP (NERU) TEST
. 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.
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- Engine vibration - mostly at coast/neutral coast. Condition improves with vehicle acceleration
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- Engine vibration or shudder - occurs with light to medium acceleration above 56 kmh (35 mph)
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- Worn or damaged spark plugs
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- INSPECT the fuel for contamination. DRAIN the fuel system and refill. REFER to FUEL TANK DRAINING
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