How to Replace the Serpentine Belt on a 2016 Subaru Legacy (Accessory Drive Belt)
Step-by-step tensioner release, belt routing tips, required tools/parts, and post-install checks for 2015, 2016, 2017, 2018, 2019
How to Replace the Serpentine Belt on a 2016 Subaru Legacy (Accessory Drive Belt)
Step-by-step tensioner release, belt routing tips, required tools/parts, and post-install checks for 2015, 2016, 2017, 2018, 2019
đź”§ Legacy - Serpentine Belt Replacement
The serpentine belt (accessory drive belt) turns key parts like the alternator and A/C compressor. Replacing it is mostly about safely relieving the automatic belt tensioner, swapping the belt, and confirming the ribs are seated correctly on every pulley.
Difficulty Level: Intermediate | Estimated Time: 0.5-1.0 hours
⚠️ Safety & Precautions
- 🧤 Work on a cool engine; hot pulleys/belt can burn you.
- đź§Ż Keep fingers/tools clear of the belt path; the tensioner is spring-loaded and snaps back hard.
- 🧱 If you go under the front of the car, support it with jack stands—never rely on a floor jack.
- 🔋 Battery disconnect is not required, but keep the key away so nobody can start the engine.
đź”§ Required Tools
You'll need the following tools for this repair:
- 14mm box wrench
- 14mm socket
- 3/8" drive ratchet
- 3/8" drive breaker bar (18"-24")
- 10mm socket
- Trim clip removal tool
- Flashlight
- Mechanic gloves
- Safety glasses
- Wheel chocks
- Floor jack (rated 2-ton minimum)
- Jack stands (rated 2-ton minimum)
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Serpentine belt (accessory drive belt) - Qty: 1
- Engine under cover clips - Qty: 2-6 (optional)
đź“‹ Before You Begin
- Park on level ground, shift to Park, set the parking brake, and use wheel chocks.
- Open the hood and take a clear photo of the belt routing (your “routing diagram” reference).
- If access is tight from the top, plan to remove the front lower splash/under cover for more room.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Create working room at the front of the engine
- Use a flashlight to locate the belt and the belt tensioner (the spring-loaded arm that keeps the belt tight).
- If needed, remove the air intake snorkel/duct for hand space: use a 10mm socket and 3/8" ratchet for bolts, and a trim clip removal tool for plastic clips.
- Bag clips/bolts so nothing gets lost.
Step 2: (Optional) Remove the lower engine under cover for better access
- Lift the front safely using a floor jack (rated 2-ton minimum) and support with jack stands (rated 2-ton minimum).
- Remove the under cover fasteners using a trim clip removal tool and 10mm socket.
- If you reinstall under cover bolts: Torque to 7.5 Nm (66 in-lbs).
Step 3: Relieve belt tension (automatic tensioner)
- Place a 14mm socket on a 3/8" breaker bar (18"-24") and fit it onto the tensioner’s hex point (this is the built-in “wrench point” for releasing tension).
- Rotate the tensioner smoothly to relieve tension. Move slowly—spring force is strong.
- While holding tension off, slide the belt off the easiest top pulley (often the alternator pulley) by hand with mechanic gloves.
Step 4: Remove the old belt and inspect pulleys
- Slowly let the tensioner return to its resting position using the breaker bar. Do not let it snap back.
- Remove the belt fully from all pulleys.
- Use a flashlight to inspect pulleys for wobble, heavy rust, or rough bearings (a bad pulley can ruin a new belt fast).
Step 5: Route the new belt correctly
- Match the new belt length to the old one on the ground to confirm it’s the same.
- Route the belt around the pulleys following your photo/routing sticker. Make sure the ribbed side sits in ribbed pulleys, and the smooth side sits on smooth pulleys.
- Leave the easiest-to-reach top pulley for last (so you can “slip it on” while holding the tensioner).
Step 6: Re-apply tension and seat the belt
- Use the 14mm socket and breaker bar to rotate the tensioner again.
- Slip the belt onto the last pulley, then slowly release the tensioner.
- Use a flashlight to confirm the belt ribs are centered and fully seated on every pulley (no ribs hanging off an edge).
Step 7: Reinstall removed parts
- Reinstall the air intake snorkel/duct using the 10mm socket and trim clip removal tool.
- If removed, reinstall the under cover using the 10mm socket and trim clip removal tool.
âś… After Repair
- Start the engine and let it idle for 30-60 seconds while you watch the belt track straight (no wandering).
- Listen for chirping/squealing. If you hear it, shut off and re-check belt seating on every pulley.
- Turn A/C on and off once and verify no unusual noises.
- After a short test drive, do a final quick visual check with a flashlight.
đź’° DIY vs Shop Cost
Shop Cost: $180-$350 (parts + labor)
DIY Cost: $25-$60 (parts only)
You Save: $155-$290 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 hours.
🎯 Ready to get started?
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