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BELT TENSIONER

For an internal combustion engine to work properly timing is everything, as many different components need to work 'as one' for the engine to run at all. The timing belt tensioner has a crucial part to play in orchestrating this performance.

Install Level of Difficulty

MODERATE

What Is a Belt Tensioner?

The belt tensioner helps to ensure that the belt to which it is attached works perfectly under all circumstances. If the tensioner were to fail and allow the belt to lose its tension under heavy load, catastrophic damage could ensue to the engine or other components could simply stop. Therefore, this device needs its fair share of attention and should be carefully set in accordance with manufacturer instructions.

How Does a Belt Tensioner Work?

The timing belt is at the heart of any engine operation, as it effectively connects several crucial components such as the water pump, air conditioner, power steering pump and alternator and provides the drive to enable each of those components to spin properly.


The main source of energy is the engine’s crankshaft, which is being turned at high speed by the pistons as the mixture 'explodes' in sequence above them. The belt also connects the crankshaft to the camshaft, to make sure that those explosions happen at just the right time. The timing belt makes sure that each of the crucial components works in synchronicity with each other and the tensioner provides just the right amount of that tension to make this happen. It’s a relatively simple set up comprising a pulley, spring and an adjustment device, but it’s crucial to ensure that the adjustment is made very carefully in all cases.

How Is a Belt Tensioner Made?

A timing belt tensioner comes in a kit, which has a frame/bearing and pulley to 'steer' the tensioner in place, a spring to make sure that the belt is always tight and a metal arm for adjustment purposes.

How Can a Belt Tensioner Fail?

  • Corrosion
  • Bearing failure
  • Cracking
  • Failed spring

What Are the Symptoms of Belt Tensioner Failure?

  • Noisy belt
  • Failure of service components

What Are the Consequences of Belt Tensioner Failure?

  • Vehicle fails to start
  • Internal damage to the engine

Considering the risk associated with failure, the timing belt tensioner should be replaced whenever the vehicle is due for a major service and especially when the timing belt itself is replaced.


If you have questions or concerns about Belt Tensioners or any of your vehicle's components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.