🔧 Fusion - Serpentine Belt Replacement

On your Fusion, the serpentine belt (accessory drive belt) turns engine-driven accessories. Replacing it is mostly about getting safe access, relieving belt tension (or stretching a “stretch-fit” belt on), and routing the new belt correctly.

Difficulty Level: Intermediate | Estimated Time: 1.0–2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine; hot pulleys and coolant parts can burn you.
• ⚠️ Keep hands/tools away from any orange high-voltage cables and connectors (hybrid system wiring).
• ⚠️ Use jack stands any time the car is lifted; never rely on a jack alone.
• ⚠️ If you disconnect the 12V battery, use a 10mm wrench and remove the negative terminal first.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• 21mm socket
• Breaker bar (1/2" drive)
• Ratchet (3/8" drive)
• 8mm socket
• 10mm socket
• Flat trim clip removal tool
• 15mm socket
• Serpentine belt tool (specialty)
• Belt stretch installer tool (specialty)
• Torque wrench (10–200 Nm range)
• Mechanic gloves
• Safety glasses
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Serpentine belt - Qty: 1
• Lower splash shield fasteners/clips - Qty: 1 set
• Serpentine belt tensioner - Qty: 1 Optional if noisy or weak

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Power the car OFF and keep the key fob at least 10 feet away so the system can’t wake up.
• Open the hood and use a flashlight to find the belt routing diagram (often on a sticker). If it’s missing, take a clear photo of the current routing.
• Tip: Draw a simple belt routing sketch.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and secure the front right corner

• Place wheel chocks behind the rear wheels.
• Use a 21mm socket and breaker bar to crack loose the right-front lug nuts (do not remove yet).
• Lift the right-front using a floor jack, then support the car with jack stands.
• Remove the lug nuts with a 21mm socket and take off the wheel.

Step 2: Remove the splash shield/inner fender access

• Use an 8mm socket and 10mm socket to remove any small bolts/screws holding the lower splash shield and/or inner fender liner.
• Use a flat trim clip removal tool to pop out plastic push-clips (pry the center up first, then remove the clip).
• Pull the shield/liner back enough to clearly see the belt and pulleys.

Step 3: Identify which belt system you have (tensioner vs stretch-fit)

• Look for a spring-loaded arm with a pulley on it (that’s the belt tensioner, which automatically keeps belt tight).
• If you do not see a tensioner and the belt looks very tight with smooth pulleys, you may have a stretch-fit belt (a belt designed to be installed by stretching it on with a special tool).
• Assumption: Many Fords use a 15mm tensioner hex; both methods are provided below.

Step 4A: Remove the old belt (if equipped with a tensioner)

• Install a 15mm socket on the tensioner bolt/hex using a serpentine belt tool (specialty) or a ratchet (3/8" drive).
• Rotate the tensioner to relieve belt tension (it will feel springy).
• While holding tension off, slide the belt off the easiest-to-reach pulley.
• Slowly release the tensioner back to its resting position.
• Remove the belt from the remaining pulleys and take it out.

Step 4B: Remove the old belt (if it is a stretch-fit belt)

• Do not pry the belt off with a screwdriver; that can damage pulleys.
• Install the belt stretch installer tool (specialty) following the tool’s orientation markings.
• Use a ratchet (3/8" drive) on the crank pulley bolt (or the tool’s drive) to rotate the engine and walk the belt off.
• Remove the belt from all pulleys.

Step 5: Inspect pulleys and tensioner

• Spin each pulley by hand and listen/feel for roughness or wobble.
• If the tensioner pulley is noisy or the tensioner feels weak/jerky, plan to replace the serpentine belt tensioner.
• Tip: A squeal on startup often points to a weak tensioner.

Step 6A: Install the new belt (tensioner style)

• Route the new belt around the pulleys exactly like your routing diagram/photo, leaving the easiest pulley for last.
• Rotate the tensioner with the 15mm socket and serpentine belt tool (specialty) to create slack.
• Slip the belt onto the last pulley, then slowly release the tensioner.
• Visually confirm the belt ribs are fully seated in every grooved pulley (no ribs hanging off).

Step 6B: Install the new belt (stretch-fit style)

• Route the new belt on all pulleys except the final one you’ll “walk on” (commonly the smooth pulley).
• Install the belt stretch installer tool (specialty) per its instructions.
• Use a ratchet (3/8" drive) to rotate the engine and walk the belt fully onto the pulley.
• Remove the tool and confirm the belt is centered and fully seated.

Step 7: Reinstall splash shield and wheel

• Reinstall the liner/shield using the 8mm socket, 10mm socket, and any clips using the trim clip removal tool (press clips fully seated).
• Reinstall the wheel and hand-thread the lug nuts.
• Lower the car off the jack stands using the floor jack.
• Tighten lug nuts in a star pattern using a torque wrench: Torque to 135 Nm (100 ft-lbs)

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✅ After Repair

• Start the car and watch the belt for 30–60 seconds. It should run smoothly with no wandering.
• Listen for squealing, chirping, or grinding. If you hear noise, shut it off and re-check belt seating on every pulley.
• Take a short test drive, then do a quick re-check for belt alignment.

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💰 DIY vs Shop Cost

Shop Cost: $180–$350 (parts + labor)

DIY Cost: $25–$70 (parts only)

You Save: $155–$280 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0–1.5 hours.

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🎯 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.