How to Change a Serpentine Belt

Replacing a serpentine belt poses challenges due to the complexity involved, particularly in the removal of the tensioner and the precise routing required for the new belt installation. The intricacies of this task demand attention to detail as an incorrect installation could result in severe consequences. Mistakes might lead to damaging the vehicle's electrical system, potential engine overheating, and, in the worst scenario, complete vehicle breakdown, leaving individuals stranded on the roadside. Given the critical importance of correctly fitting and routing the belt, seeking professional assistance is highly recommended for most individuals. Understanding that the serpentine belt connects and is propelled by the engine crankshaft pulley, its role encompasses driving various front-mounted engine accessories such as the power steering pump, alternator, water pump, and, if equipped, the smog pump.

What is a Serpentine Belt?

The serpentine belt is connected to and moved by the engine crankshaft pulley. In turn, the belt drives all of the front-mounted engine accessories including the power steering pump, alternator, water pump and smog pump if equipped.

Over time, serpentine belts that are wearing out will become cracked and brittle, indicating it is time for replacement. Serpentine belts are extremely important because if they break, the engine will eventually stop running and you will lose power steering. In addition, a broken belt can cause engine damage if the water pump is belt driven and the engine is allowed to overheat.

Routing of a Serpentine Belt

The correct routing of a serpentine belt is vital for optimal engine function, dictating its path around essential components like the alternator, water pump, and power steering pump. Following diagrams or guides available in the owner's manual or under the hood is key, ensuring the belt fits snugly around each pulley without excessive slack, preventing slippage or premature wear. Regular inspection for signs of damage or wear, along with proper tension and alignment, is crucial. Automatic tensioners, present in some vehicles, help maintain tension; if issues arise, seeking guidance from a mechanic or referring to the vehicle's service manual is advisable. Overall, the serpentine belt's correct routing and maintenance are paramount for powering critical vehicle components and ensuring reliable engine performance.

Part 1 of 2: Remove the Serpentine Belt

Suggested Materials Needed

How to Replace a Serpentine Belt 2

Step 1: Locate the Serpentine Belt Routing Diagram

Locate the serpentine belt routing diagram before removing the belt. This diagram will ensure that you know how to reinstall the belt. Most of the time, the diagram is mounted somewhere in the engine compartment. If not, you’ll need to consult the factory repair information or take a picture of the belt routing prior to removal.

How to Replace a Serpentine Belt 3

Step 2: Move the Tensioner

To loosen a serpentine belt tension, the process typically involves moving the tensioner away from the belt. However, the exact method can vary depending on the vehicle's design

How to Replace a Serpentine Belt 4

Here's a general guideline:

Identify the Tensioner

  • The serpentine belt tensioner is a pulley mounted on a spring-loaded arm or a screw-type mechanism that keeps the belt tight.

Determine the Type of Tensioner

  • Spring-Loaded: Most modern vehicles have an automatic, spring-loaded tensioner. This type requires a tool (like a ratchet or a special tensioner tool) to rotate the tensioner arm, relieving the tension on the belt.

  • Screw-Type or Manual Tensioner: Some older or specific models might have a manual tensioner, which is adjusted by loosening a bolt and manually moving the tensioner.

Loosening the Tension

  • Spring-Loaded Tensioner: Attach the tool to the tensioner's bolt head or square drive slot. Rotate the tensioner arm in the direction that relieves tension on the belt (this is usually away from the belt). This movement will create enough slack in the belt to remove it.

  • Screw-Type Tensioner: Loosen the locking bolt and then turn the adjusting bolt to move the tensioner, thereby loosening the belt.

Safety and Precautions

  • Engine Off: Always ensure the engine is off and the keys are removed from the ignition before attempting any work on the serpentine belt.

  • Direction of Movement: The direction to move the tensioner can vary. Most tensioners move clockwise, but some may require counterclockwise movement. Consult your vehicle's manual for specifics.

  • Avoid Over-Loosening: Be careful not to loosen the tensioner more than necessary, as over-loosening can lead to misalignment or damage.

How to Replace a Serpentine Belt 5

Step 3: Remove the Belt

While still holding the tensioner away from the belt, slide the belt off the pulleys.

Part 2 of 2: How to Install the New Serpentine Belt

How to Replace a Serpentine Belt 6

Step 4: Determine how to Route the Belt

Look at the belt routing diagram or the picture you took to determine how to install the new belt.

How to Replace a Serpentine Belt 7

Step 5: Move the Tensioner

Use a ratchet or serpentine belt tool to push on the tensioner and move it away from the belt, so the new belt can be installed on the pulleys.

How to Replace a Serpentine Belt 8

Step 6: Install the New Belt

Position the new belt on the pulleys. Once the belt is in place, let go of the tensioner. Double check the belt installation against the routing diagram or the picture you took to ensure it is routed properly.

Note that serpentine belt replacements can be tricky depending on what kind of car you have. This is a job you should leave to a pro. YourMechanic offers expert serpentine belt replacement at a time and place of your choice.

Next Step

Schedule Serpentine/Drive Belt Replacement

The most popular service booked by readers of this article is Serpentine/Drive Belt Replacement. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE


The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Serpentine/Drive Belt Replacement reviews

Excellent Rating


Rating Summary


21 years of experience
1307 reviews
21 years of experience
Pontiac Grand Am V6-3.4L - Serpentine/Drive Belt - Wheat Ridge, Colorado
My Mechanic was respectful and I enjoyed talking with him and he explained what he was going to do. He also told me what little things I needed to do.
Mini Cooper - Serpentine/Drive Belt - Denver, Colorado
Robert was very patient and allowed us to get the right part after we purchased the wrong one. Thanks so much!


29 years of experience
405 reviews
29 years of experience
Toyota Matrix L4-1.8L - Serpentine/Drive Belt - Alameda, California
Lavell was amazing! Great communication and expertise. Quick service with detailed explanation. All done with care and professionalism.
Chevrolet Sonic - Serpentine/Drive Belt - Lafayette, California
Lavell is absolutely wonderful. Very knowledgeable and very quick! I love his transparency when diagnosing car problems. I appreciate all of the help, thank you, Lavell!


38 years of experience
613 reviews
38 years of experience
Nissan Versa Note L4-1.6L - Serpentine/Drive Belt Replacement - Henderson, Nevada
Raymond is super awesome and fixed the belt on our car super fast and was super nice I would definitely hire him again.


16 years of experience
657 reviews
16 years of experience
Ford Taurus V6-3.0L - Serpentine/Drive Belt Replacement - Portland, Oregon
Andrew was very nice and pleasant. He was very thorough with his work and he really went out of his way to get my car running again. He was very knowledgeable and he was kind enough to answer all of my questions in a way that I could easily understand. This was one of the best experiences I have had working with a mechanic.

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