Guide on Serpentine Belt- Functions, wear & tear, replacement tips (2024)

Table of Contents

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 on 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 used 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 and 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 pre-decided time and change it as per standard guidelines.

The 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 the 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 last?

As a general rule, the serpentine belt should 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 quickly inspecting the belt condition. When the serpentine belt fails suddenly, there may be chances of sticking the car in the middle of the road, or it will turn to damage the car or any person.

Serpentine belt diagram

Guide on Serpentine Belt- Functions, wear & tear, replacement tips (1)

Which accessories are driven by the serpentine belt?

The serpentine belt transmits power to drive 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 present 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 the steering assembly is open, and the pump pushes fluid into 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 it to various processes like condensing and evaporating to transfer the energy to cool the air.

4. Water Pump

The function of the water pump is to distribute the water to the various parts of the car and engine. If the water pump stops working, 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 using a socket wrench or belt tensioner tool.
  5. Pull the belt from the pulley slowly by slowly releasing the belt tensioner and removing the belt.
  6. Place a new belt on the idler pulley as mentioned in the belt manual.
  7. Slowly compress the belt tensioner in such a way that it will place on all pulleys.
  8. Take a visual inspection of 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 & the 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 labor cost per hour gives you the total cost required to change the serpentine belt.

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

2. Additional Cost

The additional cost we have to take into account. It is due to a sudden failure of the serpentine belt that 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 to the engine, and it will be more costly to us.
Another reason for the 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 are damaged. 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 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 serpentine belt

The following symptom shows our serpentine belt is starting to warn and will fail suddenly.

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

  • If squealing or chirping sounds come 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, it stops the power steering and air conditioning. 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 the engine

  • As the serpentine belt fails, then any part or peripheral devices will not work. The central 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 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 & 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.
  • Stop the working of these devices, engine cooling not happens and may damage them.
  • A sudden failure of the serpentine belt may cause severe damage to the entire car or a person too.

Related Posts-

  • 5 Essential Air Conditioner Parts: Names, Functions, and Diagrams
  • Engine Braking: What It Is and How It Works – An In-Depth Guide
Guide on Serpentine Belt- Functions, wear & tear, replacement tips (2024)

FAQs

What else should be replaced when replacing serpentine belt? ›

Whenever you get your serpentine belt replaced at your local Clinton service center, it's a good idea to have the belt tensioner replaced as well.

What should you do before replacing a serpentine belt? ›

Check for damage

After removing the belt, inspect it for signs of damage. Many belts wear out over time, but some wear down due to misalignment or other issues. Misalignment won't resolve itself when you replace the belt, so determine whether this is a problem.

At what mileage should you replace a serpentine belt? ›

Under ideal circ*mstances, a serpentine belt will last 60,000–100,000 miles. It's important to replace this belt as part of your vehicle's scheduled maintenance, even if it looks okay. You don't want this car part to break while you're on the road.

Should you replace the idler pulley when replacing a serpentine belt? ›

We suggest technicians change a pulley whenever a timing belt or serpentine belt is changed and vice versa, but there are eight key warning signs to look out for when a pulley goes bad: Rock – Rock the pulley back and forth. There should be no movement or play from side to side.

Can I replace serpentine belt without tensioner? ›

If your vehicle does not have an auto tensioner, insert a pry bar or piece of wood between the alternator and the engine. Run the belt over the alternator pulley, then use the bar to pry the alternator away from the engine and increase the tension on the belt. Tighten the bolts again as you apply tension.

How do you break in a new serpentine belt? ›

To break in a belt, use low gear (if available) while varying speeds and avoiding wide open throttle for 5 to 10 miles. If no low gear is available, vary at moderate speeds while avoiding wide open throttle for 50 miles. Breaking in a belt is about more than a set number of miles and avoiding high engine RPM.

What is the life expectancy of a serpentine belt? ›

Typically, serpentine belts last anywhere from 50,000 to 100,000 miles. Over time, friction and heat break them down. If you're unsure whether it's time for a serpentine belt replacement, check out the warning signs below, courtesy of the experts at the Cornerstone Ford service department!

How many hours does it take to put on a serpentine belt? ›

Plus, replacement is relatively easy, and if you're wondering how long does serpentine belt service take, it's less than an hour for most vehicles.

Does a new serpentine belt make your car run better? ›

Some rides may have an additional belt to run select accessories. Thanks to serpentine belts, your car can run more effectively and smoothly than in years past.

How much labor does it take to replace a serpentine belt? ›

The average cost for serpentine belt replacement is between $109 and $134. Labor costs are estimated between $57 and $72, while parts range between $52 and $62. Whether you go to the mechanic or do it yourself, replacing a serpentine belt costs $58 to $126.

What noise does a bad serpentine belt make? ›

One of the earliest signs of a failing serpentine belt is a high-pitched squealing or whining noise, especially during engine startup or when turning the steering wheel. This noise is typically caused by the belt slipping on the pulleys due to reduced tension or deterioration.

What should be replaced when replacing serpentine belt? ›

In addition to the belt itself needing to be periodically replaced, the tensioner pulley (and the idler pulley, if there is one) spins on bearings, and over time, they wear out.

Why is my serpentine belt wearing out so quickly? ›

Age and Wear: Over time, serpentine belts can wear out naturally. Even when it's not in use, it is still exposed to the atmosphere and is degrading. Also, environmental factors such as extreme heat and the exposure to friction and tension can cause the rubber to become brittle and crack.

Can a serpentine belt last 150000 miles? ›

Serpentine Belts

These EPDM belts are not expected to need replacement before 10 years or 150,000 miles of normal use.

Should belt and tensioner be replaced together? ›

When you find a bad tensioner pulley, you have several choices. You can replace only the pulley, or you can buy a new tensioner with a new pulley attached, or you can buy a kit with a new belt, tensioner/pulley, and idler pulley if there is one, and do it all.

What should be replaced with the timing belt? ›

When you have the timing belt replaced at a reputable service center, the service should also include a few other things. The tensioner and idler rollers should also be replaced. The technician will also inspect the crankshaft seal and the camshaft seal, replacing them if necessary.

What wears out a serpentine belt? ›

If you notice that the belt has begun to fray, have it replaced immediately. Fraying is a sign of a very worn out belt and it could break, leaving you stranded. The same goes if you observe any excessive cracking. Over time, serpentine belts become cracked due to being heated and cooled.

Should I replace a serpentine belt with an alternator? ›

Replace the belt along with your alternator even if it still looks new. Because alternators typically last around 160,000 miles (note that many alternators last a lot longer or just need brushes when they fail), it's likely you'll have to replace your serpentine belt a few times before replacing your alternator.

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