Home / Engine / Serpentine Belt (5 Symptoms & Replacement Cost)

Serpentine Belt (5 Symptoms & Replacement Cost)


The serpentine belt is found in most late model cars since the 1990s. This belt is continuous and drives a variety of peripheral components for your vehicle, depending on the model. For example, the belt to operate your engine accessories includes – alternator, water pump, power steering, air conditioning, and air pump. There is usually an idler pulley that shapes the route of the belt around your engine as well as providing tension.

Difference Between a Serpentine Belt and a Drive Belt

Drive belt configurations are usually found in older model vehicles. They typically will drive one or two components in your car. As a result, depending on the features your vehicle has, e.g., air conditioning, there may be three or more drive belt and pulleys each running one or two components. They are also referred to as v-belts due to their shape. The v-belt fits into pulleys on each element with a V-shaped pulley. A serpentine belt is flat with several grooves that fit the pulley on the various components it drives. Idler pulleys are also used in both situations.

What Causes a Belt to Produce Noises?

Automobile belts will usually last from 45,000 to 75,000 miles or three to five years. They also have been known to last much longer, depending on the type of driving. When your belt begins to make some noise, it is time to replace the belt. Car owners may hear squeaking noises or squealing sounds coming from the engine. They may also make chirping sounds.

The belt may be slightly loose, causing the belt to slip against the pulley and cause squealing. Regular auto care suggests conducting a visual inspection. If the belt is beginning to disintegrate, there may be a variety of sounds generated. Either way, it is time to have the engine looked at by a mechanic, and the belt replaced.

How Many Systems of Your Car Depend on a Serpentine Belt?

Most new vehicles are equipped with air conditioning and power steering. All gasoline and diesel vehicles have water pumps for cooling and an alternator to generate electricity to charge the car battery and run various electrical components in the car. It may also run a cooling pump for the automatic transmission. The belt will operate all of these components. Note: If the serpentine belt breaks, all of these components will cease to function, quickly disabling your car.

  • Air Conditioner

Air conditioners(AC) in vehicles have become a standard feature in most new cars. The serpentine belt drives the cars AC compressor system, looping over a pulley at the end of the compressor.

  • Water Pump

The water pump circulates antifreeze throughout your engine and into the radiator to maintain the engine at the optimum operating temperature. Failure of the serpentine belt to drive the water pump will cause your engine to overheat potentially causing catastrophic damage. Turn your engine off immediately if the belt should break.

  • Power Steering pump

The power steering pump provides steering assistance to drivers making it easy to turn the steering wheel under all conditions. If the serpentine belt breaks, drivers will notice an immediate increase in resistance when turning the steering wheel. This is often one of the first indicators in addition to noise from the engine of problems with the belt.

  • Alternator

The alternator produces electricity for all of the electrical components of the vehicle, including lights, fans, radio’s, as well as electricity to run the engines ignition system. When a belt breaks, the alternator will stop producing electricity, and the system will begin drawing power directly from the battery. Your car can operate for a short period from battery power; however, observe the engine temperature to avoid overheating.

Common Causes for Removing the Belt

The serpentine belt may need to be removed or replaced for several reasons. Various components may fail and need to be replaced requiring the belt to be removed. The belt may also begin to deteriorate as it ages causing chirping, squealing and other noises. Replace the belt if any of these noises are heard and have all of the components driven by the belt inspected.

Belt breaks

Most people will quickly notice when the serpentine belt breaks. The air conditioning will immediately stop, and fans will blow hot air from the vents. The engine may begin to overheat, and the check engine light should illuminate. Steering will become more difficult since the power steering pump has ceased operation.

Missing chunks or wear

Regular car care and inspection of the serpentine belt may reveal missing chunks of rubber or wear and tear of the belt. While it will still operate your cars various components, it is just a matter of time before it will fail. Avoid being stranded on the side of the road. Replace the belt immediately and have all components inspected.

Squealing sounds

Squealing sounds coming from the area of the engine is a sure sign that the belt tension is not sufficient. The belt stretches and is slipping on one or more of the pulleys, which will cause it to squeal. Slipping on the pulley will also accelerate the deterioration of the belt in addition to the annoying squealing sounds. It may be as simple as increasing the tension on the belt to fix the issue. Have it inspected and take the necessary corrective action – tighten the tensioner or replace the belt.

Air Conditioner Mal Functioning

Air conditioners can malfunction in a vehicle for several reasons. It may be low on cooling fluid; a fuse may have blown, the belt that drives the AC unit could have broken, etc. If all of the other components are not working as well, it may be a broken serpentine belt. If only the AC is not working, it could be a broken v-belt, fuse, or system failure. Have a mechanic investigate and make appropriate repairs.

Warning light

The engine warning light or check engine soon light may turn on. Failure of the alternator and the car engine overheating may cause it to turn on or even begin flashing. If there are separate indicators for power steering and AC units, these warning lights may also illuminate. Have your car’s engine checked immediately, particularly if the lights are flashing. Overheating can cause catastrophic engine damage.

Car engine overheating

The worst case scenario is an overheated engine when the serpentine belt breaks. The water pump is not pumping water through the engine to cool it, and damage can occur rapidly in an engine that is overheated. Pull over to the side of the road in a safe location immediately and switch the engine off. Your vehicle may need to be towed and a new belt installed which is much preferred to replacing the motor.

Replacing the Serpentine Belt

Replacing the belt is relatively easy in most cars. Loosen the tensioner and remove the belt for inspection. If there are any signs of wear, missing or cracked rubber in the grooves, replace the belt with a new one.

  • Serpentine belt cost

Serpentine belts are relatively inexpensive. The price online can be in the range of $20 to $40 depending on make and model. Dealer costs for providing the belt and installation will be more expensive. However, the mechanic will also ensure that the belt is tensioned correctly and all components are working correctly. For example, a stiff idler or tension pulley can cause premature wear on the belt.

  • How often should you replace it?

Check your car’s manual or ask your dealer for recommendations on a replacement. They typically will last for forty to seventy thousand miles. Whenever an oil change is conducted, standard car maintenance by mechanics should include – check wiper blades, lights, belt inspection along with tire condition. If there is any indication of wear and tear, squealing, etc. replace it immediately.

  • Advantages of getting the belt replaced

Failure of the belt will cause the cooling system, steering system, AC and alternator to stop operating immediately. A vehicle will quickly become disabled and will need to be towed to a auto care shop. Replacing the belt as soon as it begins showing signs of wear or is making squealing sounds avoids the towing fee and the major inconvenience of a disabled car at the side of the road. If you think you have a wornout belt or if the engine light comes on you should schedule an appointment in the nearest auto care center to see if you need a replacement.

By obtaining a new belt your car will run smoothly and you will see an improvement on the fuel performance. A belt fail is a sign of la poor job during your cars maintenance inspection.

Serpentine Belt Tool Kit

serpentine belt tensioner tool kit

For do it yourself auto repair solutions, a serpentine belt tool kit will make the task much more manageable. Typically, these kits include various size sockets, long bar, and ratcheting wrench. Purchase a kit that is suitable for your vehicle. There are a variety of online instruction guidelines that provide advice, diagrams, and instructions. Check your car’s owners manual and follow instructions for your vehicle.

Before getting the serpentine belt replaced, either find a routing diagram online and print it for reference or draw a picture of the routing of the belt for reference when installing the new belt.

Different Types of Belts

Serpentine belts run all of the components in your engine using a single belt approach. In a few situations, there can be several belts with different routing around the engine. V-belts will be connected to a maximum of two components in the engine in addition to tensioner pulleys.

Engine Belt

The main drive pulley will be on the engine block itself attached to the crankshaft. A serpentine design will have one or two pulleys, while a v-belt design can have at least three or four pulleys, one to drive each belt. Replacing the inner belt requires that all belts are removed to facilitate installation of the worn belt.

Fan Belt

The fan belt drives the fan to cool the fluid circulating through the radiator. In late model cars, the fan belt and mechanical fan have been replaced with an electrical fan. Of course, if the alternator fails due to a broken belt, the electrical fan will also fail.

Timing Belt

A timing built connects the crankshaft and the camshaft which drives the valves that control air intake and exhaust from the combustion cylinders. It is hidden behind a cover. These belts typically should be replaced every sixty to ninety thousand miles. Failure of the timing belt can cause significant damage to your engine.

How a Drive Belt Works

The drive belt is driven from a pulley on the crankshaft and loops around the engine to connect with the AC unit, the water pump, the fan, and the power steering unit. There is usually a tensioner pulley that maintains the proper tension on the fan belt. Contact with each pulley can be increased by adding tension, or the belt will be looped so that there is more of the belt in touch with the pulley.

Video on How to Check and Change Your Belt

What is an Automatic Belt Tensioner?

An automatic belt tensioner maintains the proper tension on the belt to keep it tight and secure the adequate amount of contact with each pulley. Tensioners are usually spring-loaded automatic. However, they can also be manually tightened, or hydraulic tightened. The serpentine belt tensioner pulley must be removed or pulled back to replace the serpentine belt or v-belts using a serpentine belt tool kit tension bar. Follow instructions for your vehicle to release the tensioner pulley and replace the belts when they are worn or squealing.

Is it Safe to Drive with Squealing Sounds?

Once a belt begins to cause squealing, it is a sure sign that it has started slipping and is starting to show signs of a worn out belt. It is only a matter of time before the belt will break, and the car will be disabled. A vehicle breakdown on a road trip on a major expressway can be very unsafe compared to a breakdown in your driveway. Either can occur since a serpentine belt could break at any time once it starts squealing. Don’t procrastinate, have it looked at immediately.

Schedule an appointment for your cars maintenance immediately, also while you are in the auto care shop ask for oil changes prices and a tire quote in case you need to replace a set.


Cars serpentine belts and v-belts are responsible for running critical systems in vehicles. They typically will last for forty-five to seventy-five thousand miles. A noisy belt or squealing belt is usually an indicator of a worn belt that is not properly tensioned. This is the first sign of a potential belt failure.

Once the belt breaks, the AC, the alternator, power steering, and water pumps will no longer operate. A car becomes difficult to steer; the engine can overheat, hot air will blow from cooling vents, and the car will only operate as long as the battery charge lasts. Avoid catastrophic damage from an overheated engine by pulling over, not running the engine and calling for assistance.

Either if you own a Toyota Camry, Toyota Corolla, or any mid-size car if the engine light comes on it is a possibility that you are going to have a professional take a look at your car as soon as possible. Most of the time when you hear a squealing sound of a belt running, it is a sign of a wornout belt.

You can purchase the belt online if you have the cars bin number at any engines accessories website. Also, you don’t have to wait until a belt fail catastrophe to replace it. As soon as the belt starts slipping or you hear a squealing sound take your vehicle to the nearest car care. Make sure the mechanic to visually inspect the serpentine belt tensioner and the springloaded automatic system.

Tip: If you need any wiper blades take a look at our review.

This div height required for enabling the sticky sidebar