How to Replace the Serpentine Belt on a 2019-2024 Subaru Ascent (Accessory Drive Belt) (Engine: Flat 4 2.4L)
Step-by-step belt routing, tensioner release method, required tools/parts, and post-repair checks
How to Replace the Serpentine Belt on a 2019-2024 Subaru Ascent (Accessory Drive Belt) (Engine: Flat 4 2.4L)
Step-by-step belt routing, tensioner release method, required tools/parts, and post-repair checks for 2019, 2020, 2021, 2022, 2023, 2024
š§ Ascent - Serpentine Belt Replacement
On your Ascent, the āserpentine beltā (accessory drive belt) runs the alternator and other front-engine accessories. Replacing it is mostly about safely releasing the spring-loaded tensioner, swapping the belt, and confirming the belt is seated correctly in every pulley groove.
Difficulty Level: Intermediate | Estimated Time: 0.5-1.0 hours
ā ļø Safety & Precautions
- ā ļø Work on a cool engine; hot parts can burn you.
- ā ļø Keep hands/clothes clear of pulleys; never work with engine running.
- ā ļø The belt tensioner is spring-loaded; hold your tool firmly and release slowly.
- ā ļø If you raise the front, support the Ascent with jack standsānever rely on a jack.
- š Battery disconnect is not required, but remove the key and keep it away from the vehicle.
š§ Required Tools
You'll need the following tools for this repair:
- 3/8" drive ratchet
- 3/8" drive breaker bar (18"-24")
- 14mm socket
- 14mm combination wrench
- Torque wrench (10-80 ft-lbs)
- Trim clip remover
- Flathead screwdriver
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Wheel chocks
- Work light
- Mechanic gloves
- Safety glasses
š© Required Parts
HowToo sells all the parts you need for this repair:
- Serpentine belt (accessory drive belt) - Qty: 1
- Serpentine belt tensioner assembly - Qty: 1 (optional if noisy/weak)
- Idler pulley - Qty: 1 (optional if noisy/rough)
š Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Install wheel chocks behind the rear wheels.
- If access from above is tight, raise the front using a floor jack and support with jack stands.
- Take a quick photo of the belt routing in the engine bay (helps a lot on reassembly).
šØ Step-by-Step Instructions
Follow these steps in order:
Step 1: Open access to the belt
- Open the hood and remove any upper plastic covers blocking access using a trim clip remover and flathead screwdriver.
- If needed, remove the lower splash shield/undercover fasteners with a trim clip remover to see the crank pulley area better.
Step 2: Locate the belt tensioner
- Find the spring-loaded belt tensioner (it will have a pulley pressing on the belt).
- A ātensionerā keeps belt tight automatically using an internal spring.
Step 3: Relieve belt tension
- Install a 14mm socket on a 3/8" breaker bar (or 3/8" ratchet) onto the tensionerās hex boss/bolt head.
- Rotate the tensioner to unload the belt tension. Use smooth, steady pressure.
- While holding the tensioner rotated, slide the belt off the easiest-to-reach smooth pulley using your free hand.
- Slowly let the tensioner return to its resting position (do not let it snap back).
Step 4: Remove the old belt
- Pull the belt out from around all pulleys by hand.
- Spin each pulley by hand and listen/feel for roughness or grinding.
- If a pulley feels rough or wobbly, plan to replace the tensioner assembly and/or idler pulley.
Step 5: Route the new belt
- Compare the new belt to the old belt for matching length and rib count.
- Route the belt around the pulleys following your photo (leave the easiest pulley for last).
- Make sure the belt ribs sit perfectly in the grooved pulleys; the belt should not ride on pulley edges.
Step 6: Apply tension and seat the belt
- Use the 14mm socket and 3/8" breaker bar to rotate the tensioner again.
- Slip the belt fully onto the last pulley.
- Slowly release the tensioner so it tensions the belt.
- Visually check every pulley: the belt must be centered and fully seated in grooves.
Step 7: Reinstall covers
- Reinstall any splash shield/undercover pieces using a trim clip remover and flathead screwdriver.
- Reinstall any upper plastic covers the same way.
- If any small bolts were removed for shields, tighten with a torque wrench and 10mm/12mm/14mm socket as equipped to Torque to 7-9 Nm (62-80 in-lbs) unless a fastener is clearly larger.
ā After Repair
- Start the engine and watch the belt for 15-30 seconds; it should run smoothly with no wobble.
- Listen for chirping/squealing. If you hear noise, shut off and re-check belt seating.
- Test electrical load (headlights, rear defrost) to confirm the alternator is being driven properly.
- Recheck belt alignment after a short 5-10 minute drive.
š° DIY vs Shop Cost
Shop Cost: $180-$350 (parts + labor)
DIY Cost: $35-$90 (parts only)
You Save: $145-$260 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.0 hours.
šÆ Ready to get started?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.
Guide for Serpentine Belt replace for these Subaru vehicles
| Year Make Model | Sub Model | Engine | Body Style |
|---|---|---|---|
| 2024 Subaru Ascent | - | Flat 4 2.4L | - |
| 2023 Subaru Ascent | - | Flat 4 2.4L | - |
| 2022 Subaru Ascent | - | Flat 4 2.4L | - |
| 2021 Subaru Ascent | - | Flat 4 2.4L | - |
| 2020 Subaru Ascent | - | Flat 4 2.4L | - |
| 2019 Subaru Ascent | - | Flat 4 2.4L | - |


















