Serpentine Belt Replacement: A Step-by-Step Breakdown (+Cost) (2024)

Serpentine belts usually last a long time — reliably doing their job day in and day out. But if this belt breaks, it can bring your engine to a halt, leaving you in a tricky situation.

In moments like these, the only solution is to get a serpentine belt replacement.
But how do you go about replacing a worn serpentine belt?

Worry not!
We’ll give you a step-by-step breakdown of the serpentine belt replacement process and its associated costs, followed by some common serpentine belt questions.

This Article Contains:

  • How to Perform a Serpentine Belt Replacement (Step-by-Step)
  • How Much Does a Serpentine Belt Replacement Cost?
  • 5 Serpentine Belt Replacement FAQs
    • What Is a Serpentine Belt?
    • How Long Do Serpentine Belts Last?
    • What are the Signs of a Failing Serpentine Belt?
    • Can I Drive My Vehicle with a Bad Serpentine Belt?
    • Are Serpentine Belt and Timing Belt the Same?

Let’s begin.

How to Perform a Serpentine Belt Replacement (Step-by-Step)

Performing a serpentine belt replacement on your own isn’t impossible if you have the right tools and technical know-how.

However, if you aren’t sure how to replace the belt yourself, it’s best to opt for serpentine belt replacement services, where an expert mechanic can do the job for you.

Here’s how certified technicians will replace a worn serpentine belt:

  • Step 1: Note the belt placement
  • Step 2: Examine the tensioner
  • Step 3: Loosen and unthread the belt
  • Step 4: Check for belt damage
  • Step 5: Examine each pulley
  • Step 6: Install the new belt

To begin with, a serpentine belt replacement needs:

  • A serpentine belt tool, a ratchet, or a breaker bar
  • A belt placement tool

Let’s dig into the details of the serpentine belt replacement process:

Step 1: Note the Belt Placement

The belt path a serpentine belt weaves through is unique to each car.

To note down the fan belt placement:

  • The mechanic may take a few snapshots or sketch how the old belt winds around different pulleys, such as the idler pulley and the belt tensioner.
  • If you already have a loose belt that’s out of place, the mechanic can look for the belt routing in the driver’s manual.

Step 2: Examine the Tensioner

Before removing the worn serpentine belt, the mechanic will check the belt tensioner for any excess vibration. The tensioner pulley is what maintains the belt tension around the accessory pulleys.

A well-functioning tensioner should have a slight vibration. A properly tensioned belt should also run smoothly around the tensioner with no visible vibration. If the pulley exhibits a jerky vibration, the belt vibrates, or if the tensioner arm moves more than ¼ inch, it’s a symptom of a faulty belt tensioner.

Step 3: Loosen and Unthread the Belt

To remove the car’s serpentine belt, your mechanic needs to loosen the tensioner pulley first.

Here’s how:

  • Place the serpentine belt tool into the square-shaped ½-inch or ⅜-inch drive opening. If a serpentine belt tool isn’t available, a long-handled ratchet or breaker bar with an assortment of sockets could also work. They can snap a socket on the hex-shaped nut on the pulley itself.
  • Slowly rotate the tensioner arm as far as it can go. This will release the belt tension.
  • Remove the old belt off any smooth pulley, then release the tensioner.

Step 4: Check for Belt Damage

After removing the old belt, the mechanic will do a visual inspection for any signs of damage. They’ll look for any disintegration along the edges. Separated belt grooves or ribs also indicate a misaligned serpentine belt.

If your car’s drive belt has multiple cracks on adjacent belt ribs within an inch or has more than four cracks per inch on a single rib, you’ll need a belt replacement.

Other warning signs of a bad serpentine belt include:

  • Missing chunks from the belt ribs
  • Frayed fan belt fabric
  • Glazing on the belt’s back
  • Debris between the belt teeth or ribs

Step 5: Examine Each Pulley

Your car mechanic will use a straightedge tool to ensure that every pulley is aligned correctly. They’ll give the idler pulley and the tensioner pulley (automatic belt tensioner) a good spin to ensure that these move freely without any unusual noise.

If the idler pulley or other pulleys fail, your car’s serpentine belt can fall off and stop the power steering pump and water pump in the cooling system. The alternator and air conditioning compressor will also stop running.

The mechanic will also ensure that there are no oil leaks, as it can wear out a belt faster. They’ll brush off dirt or grime around each pulley to prevent any further misalignment, too.

Step 6: Install the New Belt

Here’s how the mechanic will install the new inventory in your car:

  • Route the new belt around the pulley path using a belt replacement tool.
  • Rotate the tensioner arm as they load the belt and wrap it around the crankshaft pulley.
  • Wrap the belt around any other grooved pulley, ensuring that the belt follows the original path given in the belt diagram.
  • Finish off the serpentine belt replacement by sliding the belt onto a non-grooved pulley.
  • Slowly release the tensioner.
  • Crank up your engine and let it run for a minute to ensure that the new serpentine belt is functioning correctly.

Now that you know how the replacement is done, let’s check out the cost involved.

How Much Does a Serpentine Belt Replacement Cost?

Serpentine belts are pretty inexpensive and have a long belt life.

A serpentine belt replacement can cost anywhere from $70-$200. If you plan to do it yourself, make sure you install the belt correctly, or you can end up harming the engine processes. Otherwise, it’s always best to have auto service professionals perform the serpentine belt replacement for you.

IMPORTANT: Replacement of a serpentine belt is usually not covered by vehicle protection plans unless the wear and tear resulted from an accident.

Next, let’s go over some common questions about serpentine belt replacement.

5 Serpentine Belt Replacement FAQs

Here are the answers to some belt replacement questions you might have:

1. What Is a Serpentine Belt?

It’s a long-winding rubber belt that drives multiple engine processes by transferring power from the engine’s crankshaft to the accessory pulleys. These include the alternator, power steering pump, air conditioner, cooling fan, and water pump.

Today, belt manufacturers make these belts with a special synthetic rubber called EPDM (Ethylene Propylene Diene Monomer). This serpentine belt material usually results in long belt life.

2. How Long Do Serpentine Belts Last?

Under ideal conditions, a drive belt can last 60,000 to 100,000 miles. You can go for a belt replacement as a part of your overall car maintenance.However, if you have serpentine belt issues or a worn or loose belt, get it replaced as soon as possible.

Car care tips: Applying a belt dressing (a specialized spray for rubber belts) can help prolong the life of your serpentine belt.

3. What are the Signs of a Failing Serpentine Belt?

If you notice any of the following signs, schedule an appointment for serpentine belt maintenance and possibly have it replaced:

A. Squealing from Power Steering or Air Conditioning

The drive belt controls engine accessories such as power steering, air conditioning compressor, water pump, etc. It takes a lot of torque for the belt to turn the respective pulleys. If you get a squealing sound when you turn the air conditioner on or while turning your car’s steering wheel, you may have a worn belt.

B. Visible Wear and Tear of the Belt

If you notice any physical damage, like cracks, frayed ends, or missing ribs, while conducting periodic inspections or routine maintenance, it’s time for a new serpentine belt.

C. Poor Air Conditioning

A worn belt can reduce the power supplied to the air conditioning compressor as it limits the motion generated by the engine crankshaft. If you feel that the air conditioner isn’t offering optimum cooling, get your car’s drive belt checked.

D. No Power Steering

The loss of power steering can also result from a faulty serpentine belt. Though there could also be other steering issues, like a lack of power steering fluid or a broken power steering pump, it’s best to get the cause ascertained by a mechanic.

E. Battery Warning Light

The serpentine belt also powers your car’s alternator pulley, which provides electrical power to the battery while the engine runs. If you notice an illuminated battery light, it means that the battery isn’t charging due to a bad alternator or a possible belt failure.

F. Squealing Noise Under the Hood

A squealing engine noise means that there’s a belt slippage. Sometimes, the bearing of the tensioner pulley can wear out and reduce the belt tension. In such a case, a new serpentine belt isn’t required. Fixing the bearings should resolve the issue.

Car care tips: Regular inspections of the belt can help you prevent any of these signs.

4. Can I Drive My Vehicle with a Bad Serpentine Belt?

Driving your vehicle with a faulty serpentine belt isn’t recommended, as serpentine belt issues can turn up suddenly. The belt can even roll around the engine compartment and damage other vital systems of your car.

If you don’t get a serpentine belt service soon, your car will rapidly overheat, and the engine will self-destruct in no time. If you notice signs of a possible belt failure, pull over immediately and call for roadside assistance.

5. Are the Serpentine Belt and Timing Belt the Same?

A serpentine belt is also known as an accessory belt, drive belt, or fan belt. It is not the same as timing belts.

A timing belt is located inside the engine of your car. It keeps the crankshaft and the camshaft in sync so that the engine can run smoothly. On the other hand, a car’s serpentine belt or the drive belt is located outside the engine and keeps the engine accessories, like steering, air conditioner, etc., running.

Another difference between a timing belt and a serpentine belt is that timing belts have horizontal “teeth” to fit into the cogwheels of the crankshaft. In contrast, the other has v-shaped grooves running vertically along the belt.

Closing Thoughts

If your car makes an unusual noise or the engine accessories stop working optimally, it could indicate serpentine belt issues. So, instead of towing your car to an auto repair shop, take the help of mobile serpentine belt replacement services from AutoNation Mobile Service.

With AutoNation Mobile Service, you get:

  • Convenient online booking for all your auto repair and maintenance services
  • Expert technicians who perform vehicle repairs and maintenance using new inventory
  • 12-month | 12,000-mile warranty on all repairs
  • Competitive and upfront pricing
  • Repairs and maintenance using high-quality replacement parts

For an accurate estimate of how much a fully functioning belt will cost, just fill out this form.

Serpentine Belt Replacement: A Step-by-Step Breakdown (+Cost) (2024)

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