2015–2020 Ford F-150

2015-2020 Ford F-150 - Serpentine Belt

By Ray Delgado ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 22, 2026

🔧🔧 Moderate 1–2 hours $45 DIY

Save $135 by doing it yourself! Shop cost: $180

Quick answer: Serpentine Belt on a 2015–2020 Ford F-150 is rated Moderate and takes about 1–2 hours. You'll need 6 tools for this job, and parts cost about $45. This guide walks you through the full job step by step, including the mistakes to avoid.

Quick Video Tutorial

Parts You Need

Total Cost

$45.00

Part Name	Part Number	Price	Buy
Serpentine belt (matching routing)	—	$45.00	Amazon

About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.

💡 Pro tip: Order all parts at once to save on shipping

Step-by-Step Instructions

Follow these steps carefully

Inspect the belt and identify your engine’s layout

Engine OFF: inspect the belt for cracked or missing ribs, fraying edges, glazing, or a belt off-center. Confirm your engine on the emissions label before ordering parts.

Photograph the routing and find the decal

Photograph the belt around every pulley from several angles — on EcoBoost trucks the lower pulleys are hard to see, so photos are non-negotiable. Decal missing or unreadable? Pull the routing from a service manual for your year and engine — never guess.

🔧 Mechanic's note — Tom Becker

I've re-routed too many belts from blurry phone photos. Get down low and shoot every pulley twice — five minutes of photos costs less than the second teardown when you're off by one groove.

Gain access — usually from below and the wheel well

The 13th-gen F-150’s engine bay is tight at the front drive. The practical approach on the 3.5L EcoBoost is from underneath: safely raise and support the front of the truck, remove the lower aero/splash shield fasteners, and many owners also pull the passenger-side front wheel and the inner fender liner for a straight shot at the crank pulley and tensioner. Disconnect the negative battery cable first. A headlamp is worth its weight here — the tensioner hides in the shadows below the alternator.

🔧 Mechanic's note — Tom Becker

A regular breaker bar will hit the radiator support on these trucks — ask me how I know. The short swivel-head mini bar is the only one that swings in that bay.

Rotate the tensioner counterclockwise and free the belt

Find the automatic tensioner on the engine front — it has a 3/8-inch square drive hole in the arm. Feed the belt off the remaining pulleys.

Inspect all pulleys while the belt is off

Check the tensioner arm's spring action; Ford tensioners have wear-indicator marks, and a pointer outside the normal range means a new assembly. Spin the alternator and A/C compressor pulleys — a seized compressor is a common reason EcoBoost belts snap.

Verify the belt is centered and seated

Verify the belt is centered on every pulley with all ribs seated — then check twice more, because the lower crank pulley is nearly blind from above.

Reassemble, start, and verify under load

Reinstall the splash shield, fender liner, and wheel; torque the lug nuts to spec and reconnect the battery. Drive 10 minutes with the A/C on max, headlights and blower on to fully load the belt, then confirm it's still centered and quiet.

All Done!

Test your repair before closing everything up. If something doesn't work right, double-check your steps.

⚠️ Common Mistakes to Avoid

• Trying to swing a full-length serpentine-belt tool in the cramped 3.5L bay — a short breaker bar with a swivel head actually fits
• Forgetting the separate A/C stretch belt exists and leaving a cracked one in place while replacing only the main belt
• Prying the stretch-fit A/C belt on with a screwdriver instead of the proper install tool, which damages the belt's internal cords

Tools You'll Need

3/8-inch-drive breaker bar or low-profile long ratchet with swivel head (tensioner) Jack and jack stands Socket set (splash shield fasteners, lug nuts) Stretch-belt install tool (only if replacing the A/C stretch belt) Torque wrench (lug nuts) Phone camera (routing photos) Headlamp Gloves

⚠️ Safety First!

• Support the truck on jack stands — never work under a vehicle held only by a jack.
• Disconnect the negative battery cable before working near the alternator's live terminal.
• Release the tensioner slowly; a snapping arm can break fingers. Keep clear of the belt and fan with the engine running.