- Idle air control (IAC) valve moan - occurs on throttle tip-out
|
- IAC valve is contaminated with oil.
|
|
- Accessory drive belt chirp - occurs at idle or high idle, cold or hot. Most common occurrence is during humid weather
|
- Accessory drive belt worn, or pulley is misaligned or loose.
|
- INSPECT for loose or misaligned pulleys. CHECK the drive belt for wear or damage. INSTALL new pulley(s) or drive belt, as necessary. REFER to ENGINE
.
|
- Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately +4°C (+40°F) or colder at first start of the day
|
- Accessory drive idler or tensioner pulley bearing is experiencing stick/slip between ball bearings and bearing race.
|
|
- Power steering moan - occurs at high idle and possibly at idle during the first cold start of the day in temperatures of approximately -18°C (0°F) or colder. Noise can even be a severe screech for less than one minute in very cold temperatures of approximately -29°C (-20°F) or colder
|
- High fluid viscosity, or plugged reservoir screen in power steering reservoir starves pump causing cavitation.
|
|
- Generator whine - during high electrical loads at idle or high idle, a high pitched whine or moan is emitted from the generator
|
- Generator electrical field noise.
|
- Using an EngineEAR, PROBE near the generator housing. LISTEN for changes in the noise level while changing electrical loads (such as rear defrost, headlamps, etc.). CARRY OUT a generator load test. If the system passes the load test, the noise is from the generator bearings, INSTALL new bearings. If the system fails the load test, INSTALL a new generator. REFER to GENERATOR AND REGULATOR
.
|
- Engine-driven cooling fan moan - occurs during the first start of the day. It is most objectionable near idle speeds up to 2000 rpm. The noise increases with rpm
|
- The viscous cooling fan clutch engages until the fluid in the clutch reaches normal operating temperature, causing the fan to fully engage.
|
|
- Engine cooling fan boom/rough engine idle sensation - occurs during idle when the engine cooling fan is in HIGH mode. Condition will only occur with A/C system ON and in ambient temperatures equal to or greater than 80°F (27°C). Vibration felt through steering wheel
|
- Out-of-balance engine cooling fan.
|
- TURN the A/C system ON, disconnect the ECT electrical connector. This will force the PCM to turn the cooling fans to HIGH SPEED operating mode. If engine boom, rough idle sensation or engine noise is experienced, determine if either the RH, LH or both engine cooling fans have an abnormally high shaking force. This is done by placing one's hand at each of the fan assembly's exterior shrouds and in the area where the fan assemblies mount to the radiator support. INSTALL a new RH, LH or both engine cooling fans. REFER to ENGINE COOLING
. RECONNECT the sensor and CLEAR the pending DTC Code P0118 ECT Hi Input.
|
- Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold. Very low-frequency drumming is very rpm dependent
|
- Exhaust system vibration excites the body resonances inducing interior noise.
- Engine vibration excites the body resonances inducing interior noise.
|
|
- Hissing noise - occurs during idle or high idle that is apparent with the hood open
|
- Vacuum leak or IAC valve flow noise.
|
- Use the Ultrasonic Leak Detector/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.
|
- Automatic transmission buzz or hiss
|
- Worn or damaged main control solenoids or valves.
|
- Using a transmission tester, activate the solenoids to duplicate sound. INSTALL new components as necessary. REFER to AUTOMATIC TRANSAXLE - 6 SPEED
.
|
- Heating, vacuum and air conditioning (HVAC) system chirp - most audible inside the vehicle. Listen for a change in noise pitch or loudness while changing the HVAC system blower speed
|
- Damaged or worn HVAC blower bearing.
|
|
- Air conditioning (A/C) clutch ticking - occurs when the compressor clutch engages
|
- Acceptable noise.
- Incorrect air gap.
|
- LISTEN to the clutch to determine if the noise occurs with clutch engagement. A small amount of noise is acceptable. If the noise is excessive, CHECK the A/C clutch air gap. INSPECT the A/C clutch for wear or damage. INSTALL a new clutch as necessary. REFER to AIR CONDITIONING
.
|
- Intermittent rattle, or scraping/rubbing noise
|
- Loose exhaust heat shield(s).
|
- INSPECT the exhaust system for loose parts using a glove or clamps to verify cause. REPAIR as necessary. REFER to EXHAUST SYSTEM
.
|
| |
- Wiring, hose or other part interfering with accessory drive belt or pulley.
|
- INSPECT accessory drive system closely verifying there is adequate clearance to all rotating components. REPAIR as necessary.
|
- Engine ticking or knocking noise - occurs during idle or high idle during the first cold start of the day
|
- Piston noise or valvetrain noise (bled down lifter/lash adjuster).
|
|
- A continuous, speed-dependent rattle from the engine - occurs during idle or high idle during the first cold start of the day and disappears as the engine warms up
|
- Piston noise or valvetrain noise (bled down lifter/lash adjuster).
|
|
- Idle vibration - a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/floorpan
|
|
|
- Idle vibration - a high-frequency vibration (20-80 Hz) or buzz, that is felt through the steering wheel or seat
|
- Exhaust system mounts bound up.
|
- VERIFY concern occurs at engine firing frequency. CHECK that the exhaust system vibrates at the same frequency as the engine. ADD 9-14 km (20-30 lb.) to the tail pipe to test, CARRY OUT Exhaust System Neutralizing .
|
| |
|
- INSPECT the body mounts. CARRY OUT a Neutral Engine Run-Up (NERU) Test. REPAIR as necessary.
|
| |
- Power steering lines grounded out.
|
- INSPECT that the power steering lines are not contacting the chassis or each other. REPAIR as necessary.
|