🔧 Highlander - Timing Belt Replacement (Clarification + Correct Repair)

Your Highlander’s 3.5L V6 uses a timing chain, not a timing belt—so there is no timing belt to replace as routine maintenance. If you’re trying to fix a squeal/chirp or cracked belt, you likely mean the engine accessory drive belt (serpentine belt), which is serviceable.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• 🧤 Work on a cool engine; hot pulleys and radiator fans can injure you.
• 🧯 Keep hands/clothes away from the belt path; never run the engine with fingers near pulleys.
• 🔋 Battery disconnect is not required, but remove the key/fob from the vehicle area so the engine can’t be started accidentally.

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🔧 Required Tools

You'll need the following tools for this repair:

• 14mm combination wrench
• 3/8" drive ratchet
• 14mm socket
• 10mm socket
• Trim clip removal tool
• Flashlight
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Engine accessory drive belt (serpentine belt) - Qty: 1
• Accessory belt tensioner assembly - Qty: 1 (only if weak/noisy)
• Accessory idler pulley - Qty: 1 (only if noisy)

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📋 Before You Begin

• 🅿️ Park on level ground and set the parking brake.
• Open the hood and find the belt routing diagram (usually on a sticker near the radiator support). Take a clear photo with your phone.
• If your Highlander has a plastic upper engine cover, be ready to remove it for access.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove covers for access (if equipped)

• Remove the upper engine cover (if present) using a 10mm socket (some covers also pull upward from rubber grommets).
• If there’s a small plastic splash/air guide blocking view of the belt, remove its clips using a trim clip removal tool.

Step 2: Locate the automatic belt tensioner

• Use a flashlight to find the tensioner pulley and the hex point on the tensioner arm.
• The automatic tensioner is a spring-loaded arm that keeps the belt tight.

Step 3: Release belt tension

• Put a 14mm combination wrench (or 3/8" drive ratchet with 14mm socket) on the tensioner hex.
• Rotate the tensioner smoothly to relieve tension, then slide the belt off the easiest-to-reach top pulley.
• Tip: Move slowly; the spring is strong.

Step 4: Remove the old belt

• With the belt loose, pull it off the remaining pulleys by hand.
• Compare old vs new belt length and rib count (the grooves must match).

Step 5: Inspect pulleys and tensioner (important)

• Spin each pulley by hand and listen/feel for grinding or roughness.
• If the tensioner pulley wobbles, squeaks, or feels rough, plan to replace the tensioner assembly.

Step 6: Install the new belt (follow routing diagram)

• Route the new belt around the pulleys exactly like your photo/diagram, leaving one easy pulley for last.
• Make sure the belt ribs sit fully in the pulley grooves (no “half-on” alignment).

Step 7: Apply tension and finish installation

• Rotate the tensioner again using the 14mm combination wrench (or 14mm socket and 3/8" drive ratchet).
• Slip the belt onto the final pulley, then slowly release the tensioner.
• Visually verify the belt is centered on every pulley.

Step 8: Reinstall covers

• Reinstall any clips using the trim clip removal tool.
• Reinstall the engine cover using a 10mm socket if bolts were used.

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✅ After Repair

• Start the engine and watch the belt for 15–30 seconds. It should run smoothly with no wandering.
• Listen for squeal. If it squeals with a new belt, the tensioner or an idler pulley may be weak/noisy.
• Recheck belt seating after a short 5–10 minute drive.

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💰 DIY vs Shop Cost

Shop Cost: $150-$350 (parts + labor)

DIY Cost: $25-$90 (parts only)

You Save: $125-$260 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.

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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.

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Quick check so I guide you correctly (pick one):

• 🔍 Do you mean the serpentine/accessory belt (squeal/cracks)?
• 🛠️ Or are you having a timing chain issue (rattle on cold start, cam/crank correlation codes like P0016)?