serpentine belt

What is a serpentine belt?

A serpentine belt is a single, continuous belt used to drive multiple peripheral devices in an automotive engine, such as an alternator, power steering pump, water pump, air conditioning compressor, air pump, etc. The belt is guided by an idler pulley and a belt tensioner. The belt tensioner may be hydraulic, spring-loaded, or maybe manual, depending upon the type of application.

The serpentine belt is used on the exterior of the engine. It is also called an accessory belt, alternator belt, or fan belt because it is used to drive various other accessories. In modern vehicles, only one belt is using to drive all other accessories by multiple idler pulleys.

If a serpentine belt in the car fails or breaks, all things will stop working, such as power steering, air conditioning, and the battery will also die. It can damage our car engine and car engine parts also. So, it is essential to inspect the serpentine belt at a predecided time and change it as per standard guidelines.

Function of the serpentine belt.

The function of the serpentine belt is to transfer the power received from the engine to drive various accessories like water pump, air pump, compressor, or alternator, which are present in the car. As our car is running, the function of a serpentine belt is constantly working.

How long serpentine belt lasts?

As a general rule, the serpentine belt should be last up to 50,000 to 60,000 miles or up to 5 years. Sometimes, it will last up to 80,000 miles without failing.

Due to heavy friction and heat, there are more chances of failing of belt. So we have to check regularly by just quickly inspecting the condition of the belt. When the serpentine belt fails suddenly, there may be chances of stuck the car in the middle of the road, or it will turn to damage the car or any person.

Serpentine belt diagram

serpentine belt

Accessories are driven by the serpentine belt.

The serpentine belt transmits power to drives various devices as follows.

1. Alternator

The alternator is a type of generator that distributes power to various parts of the car and recharges the battery. The serpentine belt drives the alternator, which is at the front side of the engine.

2. Power Steering Pump

A power steering pump is to push the fluid into the steering gearbox, which will help to turn the steering easily. When a driver turns the steering, a small port of steering assembly is open, and the pump pushes fluid in the steering shaft through which our vehicle will turn.

3. Air Conditioning Compressor

The air conditioning compressor helps to get cool air to the occupants. It compresses the fluid and sends to various process like condensing, evaporating to transfer the energy to cool the air.

4. Water Pump

The function of the water pump is to circulate the water to the various part of the car and engine. If the water pump stops working then, overheating may damage the car engine and car engine parts.

Replacement and Installation of new serpentine belt

Replacement of a serpentine belt of your own is an easy task. We have to follow the below step, which will help to replace the serpentine belt.

  1. Park our car in a garage or open space and open the engine hood to cool down the engine.
  2. Remove all other parts from the serpentine belt location.
  3. Locate the belt tensioner.
  4. Release the pressure on the belt by using a socket wrench or belt tensioner tool.
  5. Pull the belt from the pulley slowly by slowly releasing the belt tensioner and remove the belt.
  6. Place a new belt on the idler pulley as mentioned on the belt manual.
  7. Slowly compress the belt tensioner in such a way that it will place on all pulley.
  8. Take visual inspection on all pulleys and make sure that the belt is fitted on the pulley.
  9. Reinstall all removed parts in that place.

Cost to replace the serpentine belt

The cost for the serpentine belt replacement depends upon the type of car, make, model, and year of manufacturing.

1. Actual Cost

As we know, serpentine belts are very affordable cost-wise, their cost would be 25$ – 75$ depending upon where you are replacing them.

In the automobile sector, the cost depends upon how many hours one labor spends on the project. One hour is more than sufficient to replace any belt. But the cost of labor per hour gives you the total cost required to change the serpentine belt.

The total cost will go up to 150$ – 175$ including the cost of the new serpentine belt.

2. Additional Cost

The additional cost we have to take into account is because a sudden failure of the serpentine belt will cause a sudden stop of the car.

Eventually, due to the failure of the belt, there may be chances of overheating of the engine, which leads to getting extra damage in the engine, and it will be more costly to us.
Another reason for additional cost is the failure of the idler pulley on which the serpentine belt mounts.

This total cost will be the additional cost that will have to pay if any serpentine belts fail or damages. To avoid such loss is our firm duty to take necessary preventive action on them.

Serpentine belt vs timing belt

  • As the name suggests, there are two different terms and meanings for the timing belt and serpentine belt.
  • The timing belt is placed inside the engine, and it connects the camshaft and crankshaft. It will help to close and open valves when the piston moves. The timing belt has horizontal teeth which will connect the crankshaft and camshaft.
  • The serpentine belt is used to transmit power to other allied parts and keep the run engine very smoothly and efficiently. The serpentine belt has V-shaped grooves, which run vertically on the belt.
  • In both cases, it is a must to replace both belts occasionally to avoid future losses.
Sr. NoSerpentine BeltTiming Belt
1Placed Outside the engine.Placed inside the engine.
2It helps transmit power to other various parts such as the alternator, water pump, or compressor.It connects the camshaft and crankshaft.
3It has V-Shaped grooves.It has horizontal grooves.

4 symptoms of bad or failing of serpentine belt

There is the following symptom which shows our serpentine belt is starting warning and it will fail suddenly.

1. Squealing or chirping sound from the front side of the car

  • If squealing or chirping sounds coming from the front side of the vehicle, then there are more chances of the belt failing. It is due to misalignment or slipping of the belt from the pulley.
  • This issue can solve by replacing the new serpentine belt.

2. Power steering and Air conditioning failure

  • If the serpentine belt fails, then power steering and air conditioning will not work. So the engine will take more time to cool down.
  • Due to this, our car will not work or start easily. Preventive action is a must while driving a car.

3. Overheating of engine

  • As the serpentine belt fails, then any part or peripheral devices will not work. The main fact is that serpentine gives the power to cool the engine via a water pump.
  • If the water pump will not work, then it will overheat the engine and require more time to cool down. 
  • Due to such overheating, serious damage may occur to the car engine.

4. Crack in the belt

  • It is good to check the serpentine belt visually when we are taking a long journey.
  • Visual observations can find the cracks, uneven ribs or damages in ribs, or wear and tear of the belt.
  • If we see any damage, then our first duty is to change the serpentine belt immediately.

Advantages of serpentine belt

  • The main advantage of a serpentine belt is that it is more efficient because it consumes very little space in the engine area.
  • Using the single belt gives more tension, which increases the mechanical efficiency of the engine.
  • Life span is comparatively higher than others.
  • The serpentine belt helps to reduce slip which causes a reduction of load on the engine. It increases fuel economy.
  • Replacement and maintenance of serpentine belts are much easier than any other belt.

Disadvantages of serpentine belt

  • As the serpentine belt fails, it stops driving another accessory such as power steering, alternator, pump, and air conditioning.
  • Due stop working of these devices, engine cooling not happens and may damage it.
  • Sudden fail of the serpentine belt may cause severe damage to the entire car or a person too.