Drive Belt: Testing and Inspection

Drive Belt Noise
Drive belt noise may be described as a thumping noise heard at, or just above idle speed, as a result of drive belt pilling. Drive belt pilling occurs when small particles of drive belt material separate from the drive belt grooves, and form small balls or pills in the drive belt grooves. While some drive belt piling is normal, excessive pilling can cause a thump or knocking as the pills pass over various drive belt pulleys. This causes the drive belt to repeatedly jump off of and slap onto the drive belt pulleys
The thump or knocking noise easily misdiagnosed as an engine noise. In order to diagnosis drive belt pilling, adhere to the following procedure:
1. Remove the drive belt.
2. Run the engine for no more than 30 to 40 seconds, in order to confirm that the engine noise disappears.
3. Inspect the power steering pulley for proper alignment.
4. Inspect all other pulleys for excess paint, debris or pills in the grooves.
5. Clean the pulleys with a wire brush, as necessary.

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Part 2 Of 2:

Drive Belt Diagnosis





Drive Belt Diagnosis





Drive Belt Diagnosis





Drive Belt Diagnosis





Drive Belt Vibration

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Part 2 Of 2:

Drive Belt Falls Off





Drive Belt Diagnosis

General Instructions





The graphics illustrate the correct way to route the drive belt over the pulleys, and some examples of incorrect belt placement.
1. Observe the drive belt correctly installed on the pulley.
Each groove on the drive belt rests inside a matching groove on the pulley.





2. When installing a new drive belt, observe the indicator (3) on the tensioner.
A new drive belt should fall inside the minimum (1) and maximum (2) range.





3. When installing a used drive belt, observe the indicator on the tensioner.
A used drive belt should also fall inside this range.





4. Observe these incorrectly installed drive belts.
Avoid mix-positioning the belt by one or more grooves.