Component Tests Drive Belt Noise/Flutter Drive belt chirp occurs due to pulley misalignment or excessive pulley runout. It can be the result of a damaged or an incorrectly aligned grooved pulley. To correct, 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 accessory pulleys out of position in the fore/aft direction or at an angle to the straightedge. CAUTION: Do not apply any fluids or belt dressing to the accessory drive belt or pulleys. Drive belt squeal may be an intermittent or constant noise that occurs when the drive belt slips on an accessory pulley under certain conditions. A short intermittent squeal may occur during engine start-up and shut down or during very rapid engine acceleration and decelerations, such as:
These special short-term transient events are expected, and are due to the higher system inertias required to meet the electrical and cooling demands of today's vehicle systems. Constant or re-occurring drive belt squeal can occur under these conditions:
Install a new accessory drive belt tensioner if the drive belt tensioner is worn or damaged. Incorrect Drive Belt Installation CAUTION: Incorrect accessory drive belt installation will cause excessive drive belt wear and can cause the drive belt to come off the pulleys. Non-standard accessory drive belts can track differently or incorrectly. If an accessory drive belt tracks incorrectly, install a new accessory drive belt to avoid performance failure or loss of the drive belt.
Belt Tensioner - Mechanical The only mechanical check that needs to be made is a check for tensioner stick grab or bind.
Belt Tensioner - Dynamics The accessory drive belt tensioner can be checked dynamically as follows: