🔧 Highlander - Timing Belt Replacement

Your Highlander does not use a timing belt. The 3.5L V6 hybrid engine uses a timing chain, which is designed to last much longer and is not a normal maintenance replacement item like a belt.

If you are hearing rattling, have cam/crank correlation codes, oil leaks at the timing cover, or a no-start condition, the correct repair is a timing chain/timing cover diagnostic and possible timing chain service, not a timing belt replacement.

Difficulty Level: Advanced | Estimated Time: 12-18 hours

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⚠️ Safety & Precautions

• ⚠️ Your Highlander is a hybrid. The high-voltage system must be made safe before major engine work.
• ⚠️ Do not touch orange high-voltage cables or connectors unless the hybrid system has been disabled and proper waiting time has passed.
• ⚠️ The engine may start automatically if the hybrid system is left READY. Always power the vehicle fully OFF before work.
• ⚠️ Disconnect the 12V battery negative cable before engine front-cover work.
• ⚠️ Support the engine correctly before removing any engine mount brackets.
• ⚠️ This job requires accurate engine timing. One tooth off can cause poor running, fault codes, or engine damage.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 14mm socket
• 17mm socket
• 19mm socket
• 21mm socket
• 22mm socket
• 3/8-inch ratchet
• 1/2-inch breaker bar
• Torque wrench 10-100 ft-lbs
• Torque wrench 50-250 ft-lbs
• Metric wrench set 10mm-19mm
• Flat-blade screwdriver
• Trim clip removal tool
• Plastic scraper
• Harmonic balancer puller (specialty)
• Crankshaft pulley holding tool (specialty)
• Engine support bar (specialty)
• Floor jack rated 3-ton minimum
• Jack stands rated 3-ton minimum
• Wheel chocks
• Drain pan 2-gallon minimum
• Gasket scraper
• Feeler gauge set
• Paint marker
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain kit - Qty: 1
• Timing chain tensioner - Qty: 1
• Timing chain guides - Qty: 1 set
• Front timing cover gasket set - Qty: 1
• Valve cover gasket set - Qty: 1
• Crankshaft front oil seal - Qty: 1
• Water pump gasket - Qty: 1
• Engine RTV sealant - Qty: 1 tube
• Engine coolant compatible with Toyota Super Long Life Coolant - Qty: As needed
• Engine oil 0W-20 synthetic - Qty: As needed
• Oil filter - Qty: 1 if oil is changed
• Accessory drive belt - Qty: 1 if worn or cracked

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📋 Before You Begin

• 🚗 Park your Highlander on level ground, shift to Park, and set the parking brake.
• 🔋 Make sure the vehicle is fully OFF and the READY light is not illuminated.
• 🔋 Disconnect the 12V battery negative cable using a 10mm socket.
• ⚠️ Disable the hybrid system by removing the high-voltage service plug grip, then wait at least 10 minutes before working near hybrid components. The service plug grip is the removable safety disconnect for the hybrid battery.
• 🧊 Let the engine cool completely before draining coolant or removing covers.
• 📝 Use a paint marker to label connectors, brackets, and hoses as you remove them.
• 🛠️ This is not a beginner-friendly replacement job. If your goal was routine maintenance, no timing belt service is required on your Highlander.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Confirm This Is Not a Timing Belt Job

• Use a flashlight and look at the front of the engine area. Your Highlander has an internal metal timing chain behind the sealed front timing cover.
• There is no external rubber timing belt to remove or replace.
• If you are doing scheduled maintenance, stop here. Timing chain replacement is not normally required unless there is a confirmed fault.

Step 2: Raise and Secure the Vehicle

• Place wheel chocks behind the rear wheels.
• Use a floor jack rated 3-ton minimum to lift the front of your Highlander.
• Support the vehicle with jack stands rated 3-ton minimum.
• Never work under a vehicle supported only by a jack.

Step 3: Remove Front Splash Shields

• Use a 10mm socket and trim clip removal tool to remove the lower splash shield fasteners.
• Remove the splash shields and set them aside in order.
• Keep clips grouped by location.

Step 4: Drain Engine Coolant

• Place a drain pan 2-gallon minimum under the radiator drain area.
• Use nitrile gloves and open the radiator drain cock carefully by hand or with a flat-blade screwdriver if needed.
• Allow coolant to drain fully, then close the drain.

Step 5: Remove Accessory Drive Belt

• Use a 14mm socket or suitable wrench on the belt tensioner to relieve tension.
• Slide the accessory drive belt off the pulleys.
• Inspect the belt for cracks, glazing, or fraying. Replace it if worn.

Step 6: Support the Engine

• Install an engine support bar across the upper body structure and connect it to the engine lifting point.
• An engine support bar holds the engine from above when a mount is removed.
• Apply light upward tension only. Do not lift the vehicle with it.

Step 7: Remove Engine Mount Brackets as Needed

• Use 14mm socket, 17mm socket, and 19mm socket to remove the right-side engine mount bracket fasteners as access requires.
• Mark bracket positions with a paint marker before removal.
• During installation, tighten mount bracket fasteners to OEM specification for the exact bracket location. If specification is unavailable, do not guess.

Step 8: Remove the Crankshaft Pulley

• Install the crankshaft pulley holding tool to prevent the pulley from turning.
• Use a 22mm socket and 1/2-inch breaker bar to loosen the crankshaft pulley bolt.
• Use a harmonic balancer puller to remove the pulley evenly.
• A harmonic balancer puller removes the crank pulley without prying against the engine cover.
• Do not hammer on the pulley.

Step 9: Remove Valve Covers and Timing Cover

• Use a 10mm socket to remove ignition coil fasteners and valve cover bolts as needed.
• Use a plastic scraper to gently separate sealing surfaces without gouging aluminum.
• Use 10mm socket, 12mm socket, and 14mm socket to remove timing cover bolts.
• Carefully cut RTV sealant with a gasket scraper where needed.
• Do not pry between machined sealing surfaces with metal tools.

Step 10: Set Engine to Top Dead Center

• Use a 22mm socket on the crankshaft bolt area to rotate the engine by hand clockwise.
• Top dead center means cylinder number one is at the top of its compression stroke.
• Align the crankshaft and camshaft timing marks exactly before removing the chain.
• Use a paint marker to mark the chain and sprocket positions before removal.

Step 11: Remove Timing Chain Tensioner and Guides

• Use a 10mm socket and 12mm socket to remove the chain tensioner fasteners.
• A tensioner keeps the timing chain tight while the engine runs.
• Remove the timing chain guides with the correct 10mm socket or 12mm socket.
• Keep guide bolts organized by location.

Step 12: Remove and Install Timing Chain

• Remove the old timing chain carefully without rotating the camshafts or crankshaft.
• Install the new timing chain with the colored chain links aligned to the timing marks on the camshaft and crankshaft sprockets.
• Use your paint marker marks only as extra reference. The factory timing marks are the final authority.
• If any sprocket moves, stop and realign the engine before continuing.

Step 13: Install Guides and Tensioner

• Use a 10mm socket and 12mm socket to install the new timing chain guides.
• Use a torque wrench 10-100 ft-lbs to tighten guide and tensioner bolts to the exact OEM spec for each fastener position.
• Release the timing chain tensioner only after the chain and guides are installed correctly.
• Rotate the crankshaft two full turns clockwise using a 22mm socket, then recheck all timing marks.

Step 14: Reseal the Timing Cover

• Use a plastic scraper and shop towels to clean old RTV from sealing surfaces.
• Install a new crankshaft front oil seal into the timing cover.
• Apply engine RTV sealant in the same bead path used by Toyota around the timing cover sealing surface.
• Install the timing cover before the RTV skins over.
• Use 10mm socket, 12mm socket, and 14mm socket to snug bolts by hand first.
• Use a torque wrench 10-100 ft-lbs and tighten timing cover bolts in stages to OEM specification by bolt size and location.

Step 15: Reinstall Valve Covers

• Install the new valve cover gasket set.
• Use a 10mm socket to install valve cover bolts evenly.
• Use a torque wrench 10-100 ft-lbs and tighten valve cover bolts to OEM specification.
• Do not overtighten. Valve covers can crack or leak if crushed.

Step 16: Reinstall Crankshaft Pulley

• Slide the crankshaft pulley into place by hand.
• Use the crankshaft pulley holding tool to keep it from turning.
• Use a 22mm socket and torque wrench 50-250 ft-lbs to tighten the crankshaft pulley bolt to OEM specification.
• This fastener is critical. Do not estimate torque by feel.

Step 17: Reinstall Engine Mount and Belt

• Use 14mm socket, 17mm socket, and 19mm socket to reinstall the engine mount brackets.
• Use a torque wrench 50-250 ft-lbs to tighten mount fasteners to OEM specification.
• Use a 14mm socket on the tensioner to reinstall the accessory drive belt.
• Confirm the belt ribs sit correctly in every pulley groove.

Step 18: Refill Coolant and Reconnect Battery

• Use a clean funnel to refill with engine coolant compatible with Toyota Super Long Life Coolant.
• Reconnect the 12V battery negative cable using a 10mm socket.
• Reinstall the hybrid service plug grip fully and lock it into position.
• Do not make the vehicle READY until all tools are removed from the engine bay.

Step 19: Reinstall Splash Shields and Lower Vehicle

• Use a 10mm socket and trim clip removal tool to reinstall splash shields.
• Use the floor jack rated 3-ton minimum to lift slightly off the stands.
• Remove the jack stands rated 3-ton minimum and lower your Highlander slowly.

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✅ After Repair

• ✅ Start your Highlander and listen for chain rattle, knocking, or misfire.
• ✅ Check for oil leaks around the timing cover, valve covers, and crank seal.
• ✅ Check coolant level after the engine reaches operating temperature and cools back down.
• ✅ If warning lights appear, scan for codes before driving far.
• ✅ Road test gently, then recheck oil and coolant levels.
• ✅ If engine timing codes return, do not keep driving. Recheck chain timing immediately.

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💰 DIY vs Shop Cost

Shop Cost: $2,200-$4,000+ parts + labor

DIY Cost: $350-$900 parts only

You Save: $1,300-$3,100 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 12-18 hours.

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🎯 Ready to get started?

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