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What is the purpose of the tensioner pulley?

What is the purpose of the tensioner pulley?

Its primary function is to provide tension and guide the engine drive belt. These belts wrap around the various parts of the engine such as the power steering pump, alternator, water pump etc… To keep it simple, idlers are complementary pulleys that make the entire system run smoothly.

What happens when you change the serpentine belt?

Billions of rotations under constant tension of the serpentine belt will take its toll over time. The “ribs” in the pulleys get damaged so even if you change the belt, the damaged pulley will tear and shred the belt again.

Is the water pump driven by the serpentine belt?

Another important device driven by the serpentine belt is the water pump. This is not always the case as on a lot of cars the water pump is driven by the timing belt. You should have this in mind so you don’t falsely “accuse” the serpentine belt for overheating.

Why does my serpentine belt make a screeching sound?

The belt slides over a motionless pulley causing extensive friction, heat and the recognizable sound. The screeching sound may also be caused by a severely worn out serpentine belt (in this case, it must be nearly pulverized).

What causes a belt to squeak over pulleys?

Squeaking is caused because the belt is slipping over the pulleys. The slipping is caused because the belt loses ability to produce enough friction between itself and the pulleys (mostly due to material fatigue).

How is the tension set on a serpentine belt?

Depending on the application, your serpentine belt will either have tension placed on it using a movable bracket or an auto tensioner pulley. This pulley uses an internal spring to apply consistent pressure to the belt at all times. If your vehicle does not have a tensioner pulley, the alternator bracket is likely how tension is set on the belt.

What causes a serpentine belt to get stuck?

The main reason, in most cases, will be a stuck pulley from one of the devices (alternator, AC compressor, power steering pump etc) or a tensioner. A stuck pulley is mostly caused by a worn out bearing. The belt slides over a motionless pulley causing extensive friction, heat and the recognizable sound.

What’s the best way to replace a serpentine belt?

Auto tensioners have either a hole that will fit a half inch drive ratchet, or a bolt you can use a socket to apply pressure to. Insert the wrench or place the socket over the bolt on the tensioner and twist it away from the belt to relieve the tension on it.

Where do I find the serpentine belt routing diagram?

Find the serpentine belt routing diagram. Many cars come with a sticker in the engine bay that shows exactly how the serpentine belt is supposed to be routed through the various pulleys on the engine. If your vehicle does not have a sticker, you will need to find another way to remember how the belt should be run.

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Ruth Doyle