Operation CHARM: Car repair manuals for everyone.

Drive Belt Chirp

Drive belt chirp is a regularly occurring chirping noise that occurs due to:
- pulley misalignment.
- excessive pulley runout.

It can be a result of a damaged pulley or an improperly replaced pulley that was not properly aligned.

To correct drive belt chirp:
- determine the area where the noise comes from.
- check each of the pulleys in that area with a straightedge to the crankshaft pulley.
- look for the accessory pulley to be out of position in the fore/aft direction or at an angle to the straightedge.

Drive belt squeal is an intermittent noise that occurs when the drive belt slips on a pulley during certain conditions such as:
- engine start-up
- rapid engine acceleration/deceleration
- A/C clutch engagement

Drive belt squeal can occur under the following conditions:
- If the A/C discharge pressure goes above 2.895 kPa (420 psi). This can occur if:
- the A/C system is overcharged.
- the A/C condenser airflow is blocked.
- the engine cooling fan is not engaging fully at idle.

- If any of the accessories are damaged, have a worn or damaged bearing or internal torsional resistance is above normal for any reason. All of the accessories should be rotatable by hand in the unloaded condition. If any are not, the accessory should be inspected.
- If fluids get on the drive belt. This would include power steering fluid, engine coolant, engine oil and air conditioning system lubricant.
- If fluid does get on the drive belt during service, clean the drive belt with soap and water and thoroughly rinse with clean water. The drive belt does not have to be replaced if no apparent damage has occurred.
- If the drive belt is too long. This will allow the arm on the drive belt tensioner to go all the way to drive belt tensioner arm travel stop under certain load conditions and will remove the tension on the drive belt. If the drive belt tensioner is resting on the stop, replace the drive belt.

NOTE: The drive belt tensioner arm should rotate freely without binding. If the drive belt is worn or damaged, replace the drive belt.

- If the drive belt tensioner is worn or damaged, refer to Component Test. Testing and Inspection