Serpentine Belt Explained

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The serpentine belt is one of two belts or in some cases the only belt of a car. It does not affect engine working directly, but you will surely face difficulty with a bad serpentine belt. This article is all about the serpentine belt and how it works or can affect car working.

What is a serpentine belt

Serpentine belt, also called the drive belt, is a V-type belt made from rubber materials. It’s an important part of a car and it helps transfer power to several car components. To transfer power effectively a it has multiple V grooves. 

It moves between multiple pulleys having the same V grooves and some idler pulleys. There is also a belt tensioner to adjust the tension of the drive belt.

This belt is also called a fan belt, alternator belt, accessory belt, and auxiliary belt in different regions of the world.

is the serpentine belt the same as the timing belt
is the serpentine belt the same as the timing belt

What does serpentine belt do

The serpentine belt is designed and used to transfer power from the engine crankshaft to other car parts. It transfers power to components like the car AC compressor, power steering pump, water pump, air pump, and alternator. 

It takes power from the engine crankshaft and after passing through multiple pulleys, transfers that power to the AC compressor, water pump, air pump, power steering pump, and car battery alternator.

To keep the drive belt working properly, several idler pulleys and a tensioner are used. Idler pulleys ensure proper contact path and the tensioner makes sure proper tension on all pulleys. 

drive belt vs timing belt
drive belt

How to clean serpentine belt

Serpentine belts are made of rubber that does wear over time. Also, the belt is usually installed without a can cover to protect it from dust and debris. So the question of how to clean a serpentine belt is usually the question. 

To clean the drive belt, a simple clean cloth can be used. Take a clean cloth and remove as much dust and debris from the belt surface as possible. To clean the V grooves, take an old toothbrush and clean the inside of the grooves. 

If there is oil on the belt then you need to use the compatible degreaser on it. First, take a clean cloth and remove as much oil as possible. Then take a degreaser that does not react with belt rubber material. Spray a small portion of the degreaser and clean it with a cloth. If there is still some oil on the belt, repeat the process until the belt is properly clean.

How often should you change serpentine belt

You should change the serpentine belt every 80,000 to 100,000 miles. It mostly depends on the car make, model, and specific engine requirements but most belts need to be replaced after 100,000 miles. 

Several factors influence the life of the belt and you need to do regular maintenance checks on the belt. It’s highly recommended to change the idler pulleys and tensioner along with the drive belt as they have more or less the same life.

How to know if serpentine belt is bad

Following are some four main bad serpentine belt symptoms.

Unusual noise observed from the front of the car or engine

With a bad serpentine belt, unusual noise can be heard coming from the front of the car. As the belt moves over several pulleys and a tensioner, so any misalignment, crack, or broken strip, over a tight or loose belt will surely make noise. 

Car AC will not work at all with a bad belt

The drive belt takes power from the engine crankshaft and transfers it to the AC compressor through its pulley. With a bad belt, the AC compressor will not get power and thus the car AC system will not work at all.

Car power steering will not work or become hard with a bad serpentine belt

In all those vehicles that have a hydraulic-based power steering system, the pump of the hydraulic system is operated by this belt. With a bad drive belt, the hydraulic pump will not work properly or may not work at all. This will make power steering hard or not work at all.

The car engine might overheat if the serpentine belt runs the fan or water pump

If the belt in your car runs the engine cooling fan or it runs the coolant/water pump of the car. Then your car engine will heat up due to a bad belt.

Visible cracks on the belt surface

If there are visible cracks on the drive belt then the belt is already bad and it will fail shortly. It’s never recommended to drive with a bad belt as you can face difficulties in the middle of a load drive.

timing belt vs serpentine belt
timing belt vs serpentine belt

Can a bad serpentine belt cause rough idle

No, a bad serpentine belt cannot cause rough idling. Engine working and performance do not depend on this belt. A drive belt is not involved in any of the parameters or parts that affect engine working or performance. So it cannot cause rough idling.

Why does my serpentine belt keep coming off

Belt grooves have worn out or its tool is loose on its pulleys, these are mainly two reasons why your serpentine or drive belt keeps coming off. Serpentine belt has V grooves on its body to make proper grip on its pulleys and transfer power. If these grooves have worn out then it will come off its pulleys.

The serpentine or drive belt also needs proper tension to maintain its grip on pulleys and transfer power. To maintain that tension idler pulleys and tensioners are used. If this tension on the belt is not as per the manufacturer’s recommendation then it will come off. 

Can I drive without a serpentine belt

Yes, you can drive without a serpentine belt only if you have a nonhydraulic power steering system. As serpentine belts derive the hydraulic pump of power steering it will not be possible to steer around without a serpentine belt. You will also be driving without air conditioning and recharging your car battery

How long can a car run without serpentine belt

A car cannot run for too long without a serpentine belt. A serpentine belt powers the power steering, car AC, and battery alternator. So you can only drive as long as the battery has the power to power the electric power steering and other car electronics like headlights and indicators. 

In the case of hydraulic power steering, you cannot steer without a serpentine belt.

Is serpentine belt same as timing belt

No, a serpentine belt is not the same as a timing belt. Timing belt transfer synchronizes motion from crankshaft to camshaft whereas serpentine belts transfer power from crankshaft to car AC compressor and car battery alternator.

A timing belt has teeth on its surface that help transfer power whereas a serpentine belt has V grooves to transfer power. The timing belt only works with the crankshaft and camshaft whereas the serpentine belt works with the crankshaft, alternator, water pump, air pump, and water steering pump.

serpentine belt and timing belt
serpentine belt and timing belt

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