What does a idler pulley do?

  1. Reduce Wear and Tear: Idler pulleys help reduce wear and tear on the engine by maintaining proper tension on the drive belt.
  2. Support Rotation: They support the rotation of the drive belt, allowing it to move smoothly around other pulleys.
  3. Ensure Optimal Performance: Idler pulleys ensure that the drive belt remains in the correct position for optimal performance of the engine.
  4. Decrease Friction: By reducing friction, idler pulleys help improve the overall efficiency of the engine.
  5. Extend Belt Life: They help extend the life of the drive belt by preventing it from slipping or coming off track.

What happens when an idler pulley goes bad?

  1. Excessive Noise: A bad idler pulley can cause squeaking or grinding noises.
  2. Belt Slippage: The drive belt may slip off the pulley, causing a loss of power to engine components.
  3. Engine Overheating: If the idler pulley fails, it can lead to engine overheating due to improper belt tension.
  4. Increased Wear: Other pulleys and engine components may experience increased wear if the idler pulley is faulty.
  5. Complete Belt Failure: In severe cases, a bad idler pulley can lead to complete belt failure, resulting in engine damage.

Does idler pulley need to be replaced?

  1. Regular Maintenance: It is recommended to replace idler pulleys during regular maintenance intervals to prevent unexpected failures.
  2. Visible Wear: If the idler pulley shows signs of wear such as cracks, chips, or squeaking, it should be replaced.
  3. tension pulley

  4. Loss of Tension: If the drive belt loses tension due to a faulty idler pulley, it needs to be replaced.
  5. Age: Idler pulleys have a lifespan and should be replaced as they age to prevent failures.
  6. Professional Inspection: A professional mechanic can assess the condition of the idler pulley and recommend replacement if necessary.

Advantages of idler pulleys

  1. Improved Engine Performance: Idler pulleys help maintain proper belt tension for optimal engine performance.
  2. Longer Belt Life: By reducing wear and tear on the drive belt, idler pulleys help extend its lifespan.
  3. Efficiency: They improve the overall efficiency of the engine by reducing friction.
  4. Noise Reduction: Properly functioning idler pulleys can help reduce noise from the engine.
  5. Cost-Effective Maintenance: Regularly replacing idler pulleys can prevent costly repairs due to belt failures.

Process of Compound Pulley


The mold is created to form the shape of the compound pulley.

spa pulley


Raw materials are melted and poured into the mold to create the pulley shape.

Raw Materials

High-quality materials such as steel or aluminum are used to ensure durability and performance.


tension pulley

The compound pulley is manufactured with precision and attention to detail.


Each pulley undergoes rigorous testing to ensure quality and functionality.

Antirust Treatment

The pulley is treated to prevent rust and corrosion, extending its lifespan.

Separate Inspection

Each pulley is individually inspected to guarantee quality and reliability.


Finally, the pulley is marked with relevant information for identification and tracking.

What is the function of the tensioner and idler pulley?

  1. Maintain Belt Tension: Both the tensioner and idler pulley work together to maintain proper tension on the drive belt.
  2. Support Belt Rotation: They support the rotation of the drive belt, ensuring smooth operation.
  3. Prevent Slippage: By keeping the belt in place, they prevent slippage and loss of power.
  4. Reduce Friction: Tensioner and idler pulleys help reduce friction, improving overall efficiency.
  5. Extend Belt Life: By reducing wear and tear on the belt, they help extend its lifespan.
  6. Ensure Engine Performance: Properly functioning tensioner and idler pulleys are essential for optimal engine performance.
  7. Minimize Noise: They help reduce noise from the engine by maintaining proper belt tension.

How to stop a idler pulley from squeaking?

  1. Regular Lubrication: Lubricate the idler pulley with appropriate grease to reduce friction and noise.
  2. Inspect for Damage: Check for any signs of wear or damage on the pulley and replace if necessary.
  3. Adjust Belt Tension: Ensure the drive belt is properly tensioned to prevent squeaking.
  4. Clean the Pulley: Remove any debris or buildup from the pulley to eliminate noise.
  5. Seek Professional Help: If the squeaking persists, consult a mechanic for further diagnosis and repair.

About HZPT

HZPT, founded in 2006, is a leading manufacturer of precision transmission components based in Hangzhou. We specialize in producing various precision parts and complex products tailored to your needs. Before establishing our overseas sales team, we started producing 3D printer accessories, anti-theft screws and nuts, camera mounts, and more. In addition, we offer assembly production services to save time and costs. Our dedication to providing top-quality products and services has earned us a reputation among major clients in Europe and America. Choose HZPT for the best products at competitive prices.

V Pulley