Serpentine Belt Diagram and Components Functions

If you’ve ever owned a car, you’ve probably had the experience of your serpentine belt breaking in the middle of nowhere.

This can be a major inconvenience and even dangerous since the belt is responsible for turning your alternator, water pump, and all other accessories on your engine.

The serpentine belt is one of the most important parts of your vehicle because it drives all the accessories on your engine.

Your alternator, power steering pump, air conditioner compressor, and water pump are all driven by the serpentine belt.

Also known as a drive belt or fan belt, this rubberized belt connects to a pulley on each accessory and turns them at a constant speed while they’re operating.

The number of grooves in an automotive serpentine belt determines its size; for example, if there are three grooves in a serpentine belt, it will be called a “3G” or “triple groove” belt.

1. What is a Serpentine Belt?

A serpentine belt is a belt that uses a series of interconnected V-shaped pulleys to power multiple devices in an automotive engine.

The belt is so named because its path through the engine compartment resembles a snake’s spine.

The belt transmits torque from the crankshaft to the alternator, water pump, and other devices, and helps keep the engine running cool by circulating coolant.

Serpentine belts are typically made of rubber, synthetic rubber, or polyurethane. They’re usually less than an inch wide and about 12 inches long.

Some older vehicles have a single row of teeth on their belts; newer vehicles have multiple rows of teeth on their belts.

Serpentine Belt Diagram

Serpentine Belt Diagram

The serpentine belt is a single, wide belt that wraps around all of the pulleys in your engine’s accessory drive system.

The serpentine belt drives the alternator, power steering pump, air conditioning compressor, and water pump.

The serpentine belt can be removed from the pulleys without removing any other components from the engine.

Here is the serpentine belt diagram, its components, and what it does.

Drive Belt

The drive belt is responsible for transferring engine power to the accessories (power steering pump, alternator, and air conditioning compressor).

The belt also provides a source of power for engine cooling.

A broken or worn drive belt can cause several different problems including poor performance and overheat.

To check the condition of your serpentine belt, look for signs of cracking or fraying (the belt will have noticeable cracks if it is worn down).

Also, there should be no bulges or dents in the belt. Replace the belt if it shows any of these signs.

Crankshaft Pulley

The crankshaft pulley is also known as the harmonic balancer or simply balancer.

It’s a metal disc that sits on top of the crankshaft and helps dampen vibrations generated by the pistons and rods as they move up and down.

The crankshaft pulley serves no purpose during normal driving conditions, but if it comes loose or breaks off completely while you’re driving, it can cause serious damage to other components in your engine such as the timing belt or water pump.

A/C Compressor Pulley

The A/C compressor pulley is located behind the crankshaft pulley on some vehicles.

It is connected to the compressor by a drive belt that runs over the top of the crankshaft pulley and down through a groove in its center section.

The purpose of this pulley is to create a vacuum inside the car, which makes it easier for you to inflate your tires by hand, as well as provides more power when accelerating from a stoplight with your air conditioner turned off.

Power Steering Pump Pulley

The power steering pump pulley is located on the front side of your vehicle’s engine block near the crankshaft pulley.

This pulley drives the power steering pump which provides fluid pressure to your power steering system.

When you turn your wheel while driving, fluid pressure moves through this system to make turning easier for you by using less effort than if you were using manual steering.

Alternator Pulley

The alternator pulley spins as you drive your car and generates an electrical current for charging your battery and powering electronics such as headlights or stereo systems inside your vehicle’s cabins.

Without this belt, your engine would have to run at a slower speed in order to produce enough electricity to power your car’s electronic features.

However, with this belt connected, it can spin at a faster rate while still producing enough electricity for all of your electronics.

Water Pump Pulley

The water pump pulley is attached directly to the engine’s crankshaft by a long shaft that runs through its center hole.

As the crankshaft turns, it rotates this shaft which turns the water pump pulley as well.

The water pump then pushes the coolant through hoses attached to it which circulate coolant through your engine’s cylinders where combustion takes place during operation.

Idler Pulley

The idler pulley is the pulley that the serpentine belt runs over and the tensioner pulley is mounted on.

The idler pulley is usually mounted on the front of the engine, although some vehicles use a rear-mounted idler pulley.

Tensioner Pulley

The tensioner pulley is mounted on the crankshaft or camshaft and controls the amount of tension in the serpentine belt.

As it spins, it pulls on a spring-loaded bolt attached to the tensioner pulley.

This spring-loaded bolt then pulls on a cable that is connected to an adjustment dial or locknut on top of the tensioner pulley.

When you turn this adjustment dial or locknut clockwise, you are increasing the tension in your serpentine belt.

When you turn this adjustment dial or locknut counterclockwise, you are decreasing the tension in your serpentine belt.

Can I Replace a Serpentine Belt Myself?

It’s not hard to replace a serpentine belt, but you should always take it to a mechanic.

A replacement can cost up to $50 at an auto parts store and as much as $150 from a mechanic, depending on the type of car you drive and how far away you are from an auto parts store or mechanic shop.

Replacing a serpentine belt yourself requires basic tools and knowledge of how to use them.

The process isn’t difficult if you’re careful and follow instructions carefully, but it’s risky if something goes wrong — especially if there are no mechanics nearby who can help out if something goes wrong while working on your car.

If you’re unsure whether you feel comfortable replacing your serpentine belt yourself, take it to an auto shop instead.

There’s no reason to risk damaging your vehicle or injuring yourself unnecessarily when there are so many other things demanding your attention on any given day!

Get Familiar With Your Car

Before you get started, it’s important to know what type of car you have.

will help determine which instructions are appropriate for your vehicle.

The easiest way to do this is by looking at the serpentine belt tensioner pulley on your engine.

You should see letters on the pulley that indicate what type of belt was installed in your car when it was made.

Most cars have either an AC Delco or Dayco brand belt installed, but there are other manufacturers as well.

Why Do Serpentine Belts Break?

Serpentine belts break because they’re constantly under stress and strain from the moving parts in your car’s engine compartment.

They’re also exposed to extreme heat and cold every time you start and stop your vehicle, so they’re subjected to regular changes in temperature extremes — which can cause them to wear out prematurely.

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