Serpentine Belt FAQs

What does a serpentine belt do?

• A serpentine belt transfers power to your vital automotive components. The serpentine belt is one long, winding belt that keeps your air conditioning, alternator, power steering pump and in some cases your water pump running.

Didn’t cars used to have more than one belt?

• Back when cars were first made they had multiple belts for multiple components. Each one could be replaced individually, but cars would experience inconsistent or compromised performance as these individual belts began to wear down. To make things more efficient, now vehicles employ a single belt – the serpentine belt. With that being said, it is critical to have this belt regularly inspected to make sure it is in good shape.

How often does a serpentine belt need to be replaced?

• Serpentine belts are built to last. Under ideal conditions, a belt should last an average of 60,000 to 100,000 miles. However, some belts are manually tensioned and may need to be readjusted. Others have a self-tensioning mechanism that can experience wear over time and may need to be serviced. One thing to remember: in most cases, if the belt brakes then the vehicle will stop running.

What happens as a belt gets older?

• As belts get older they can wear, fray crack or become shiny or “glazed”, and rubber parts can peel off the belt. An aging belt can begin to start slipping or squealing become contaminated with fluid or become misaligned, in which case it needs to be replaced. An old belt can even snap, which can leave you stranded because without a belt, your drive torque to all of the engine’s accessories.

What is the benefit of having a belt replaced?

• Driving on an old belt is a disaster waiting to happen because it powers most of the engine’s accessories. That means when the belt breaks, slips and, ultimately wears out, everything stops working. The worst part is that parts controlled by the belt can become severely damaged from an old belt. By replacing your belt periodically, you can minimize the risk of severe damage.

What is a “belt tensioner,” and what is the benefit of replacing it when a belt is replaced?

• Many of today’s vehicles are equipped with a self-tensioning device called an automatic belt tensioner. These tensioners are designed to hold a predetermined amount of tension on the serpentine belt so it functions properly and keeps your car cruising.
• Your serpentine belt is like one giant, fast-spinning rubber band. And like a rubber band, it must maintain a balance of flexibility and tension. Most tensioners feature an internal spring and pulley, which applies the needed force against the serpentine belt to keep it tight. If there is not enough tension, a belt can slip, squeal, or run hot. Worst-case scenario: a loose belt will come off its pulleys. When this happens, all the accessories powered by the engine and the vehicle itself stop running.

How many different types of belts are there?

• A serpentine belt is the most common belt in today’s cars – it controls the functionality of almost every system in the car. Alternately, your ride may feature a series of V-belts (also known as fan belts), which perform the same all-purpose functions as a serpentine belt. Some vehicles may also have a “toothed” timing belt in the engine that is the key to overall engine performance. This belt may drive the water, oil pump and other key parts.

What are symptoms my vehicle’s belt may require a belt replacement?

• Chirp or squeal: when a belt begins to slip, a squealing sound may occur. This is the result of the belt and pulley not working correctly, low belt tension or belt stretch and/or wear. Oil and antifreeze leaks can also contribute to belt slippage. If you hear these sounds, you need to have your ride inspected as soon as possible before further malfunctions occur.
• System performance loss: maybe your power steering has failed, your battery suddenly drains or your engine just stops. All these things are controlled by a properly functioning serpentine or V-belt. Once your belt is compromised, it can produce further damage to the vital systems – such as the alternator, water pump, power steering and air conditioning – that depend on it. Unfortunately, the resulting damage can require extensive repair, with very little warning leading up to the event.
• Check engine light illumination: this may indicate something is wrong with the belt.
• Funny noises: this may be related with other parts. Never ignore a noise. Where there is a noise, there is a potential problem. Have your car inspected and keep your vehicle protected.