🔧 Highlander - Timing Chain Service

Your Highlander’s 2.7L 4-cylinder engine uses a timing chain, not a timing belt. Timing chains are designed to last much longer than belts and are usually replaced only if there is noise, stretch, guide wear, oil-pressure-related rattling, or timing correlation fault codes.

This is a major engine repair because the front timing cover must be removed and the crankshaft/camshaft timing must be set exactly. A mistake can cause poor running or engine damage.

Difficulty Level: Advanced | Estimated Time: 8-12 hours

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⚠️ Safety & Precautions

• ⚠️ Disconnect the negative battery cable before starting to prevent accidental cranking.
• ⚠️ Support the engine before removing any engine mount parts. The engine can shift if unsupported.
• ⚠️ Let the engine cool fully before draining coolant or working near the exhaust and radiator.
• ⚠️ Use jack stands any time the vehicle is lifted. Never rely on a floor jack alone.
• ⚠️ Keep the timing chain, camshaft sprockets, and crankshaft sprocket aligned exactly. Incorrect timing can damage the engine.
• ⚠️ Toyota’s sealant areas must be clean and oil-free or the timing cover may leak after repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• Metric socket set 8mm-22mm
• Metric wrench set 8mm-22mm
• 10mm socket
• 12mm socket
• 14mm socket
• 17mm socket
• 19mm socket
• 21mm socket
• 22mm socket
• 1/2-inch drive breaker bar
• 1/2-inch drive torque wrench
• 3/8-inch drive torque wrench
• Crankshaft pulley holding tool (specialty)
• Harmonic balancer puller (specialty)
• Engine support bar or floor jack with wood block
• Plastic trim clip removal tool
• Flat-blade screwdriver
• Needle-nose pliers
• Coolant drain pan
• Oil drain pan
• Gasket scraper plastic razor tool
• Brake cleaner spray
• Shop towels
• Paint marker
• Feeler gauge set
• Safety glasses
• Nitrile gloves
• Floor jack rated 3-ton minimum
• Jack stands rated 3-ton minimum

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain - Qty: 1
• Timing chain tensioner - Qty: 1
• Timing chain guide set - Qty: 1
• Crankshaft front oil seal - Qty: 1
• Timing cover sealant - Qty: 1
• Valve cover gasket set - Qty: 1
• Engine oil - Qty: 5 quarts
• Oil filter - Qty: 1
• Toyota-compatible coolant - Qty: 1 gallon concentrate or 2 gallons premixed
• Drain plug gasket - Qty: 1
• Water pump gasket - Qty: 1 if water pump is removed
• 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.
• Open the hood and let the engine cool completely.
• Disconnect the negative battery cable using a 10mm socket.
• Raise the front of your Highlander with a floor jack rated 3-ton minimum and support it with jack stands rated 3-ton minimum.
• Remove the lower engine splash shield so you can access the crank pulley and drain points.
• Plan to replace engine oil after this repair because the timing cover is sealed to oil passages.
• A harmonic balancer is the crankshaft pulley at the bottom front of the engine. It drives the accessory belt and must be removed.
• A timing chain tensioner is a spring/oil-pressure device that keeps the chain tight while the engine runs.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove Engine Covers and Splash Shield

• Use a 10mm socket to remove the plastic engine cover fasteners if equipped.
• Use a plastic trim clip removal tool to remove splash shield clips under the front of the vehicle.
• Use a 10mm socket to remove splash shield bolts.
• Set all clips and bolts in labeled containers.
• Take photos before removing parts.

Step 2: Disconnect the Battery

• Use a 10mm socket to loosen the negative battery terminal clamp.
• Move the cable away from the battery post so it cannot spring back.

Step 3: Drain Engine Oil and Coolant

• Place an oil drain pan under the oil pan.
• Use a 14mm socket to remove the engine oil drain plug.
• Install the drain plug with a new gasket after draining. Torque to 40 Nm (30 ft-lbs).
• Place a coolant drain pan under the radiator drain area.
• Open the radiator drain carefully using needle-nose pliers if needed.
• Dispose of fluids properly according to local rules in Panipat.

Step 4: Remove the Accessory Drive Belt

• Use a 14mm socket or suitable wrench on the belt tensioner.
• Rotate the tensioner slowly to release belt tension.
• Slide the accessory drive belt off the pulleys by hand.
• Draw a belt routing diagram with a paint marker or take a photo before removal.

Step 5: Remove Components Blocking the Timing Cover

• Use 10mm socket, 12mm socket, and 14mm socket as needed to remove brackets, wiring retainers, and front engine accessories that block the timing cover.
• Use needle-nose pliers to release hose clamps gently.
• Move wiring harnesses aside without pulling on the wires.
• Label connectors with tape before unplugging them.

Step 6: Support the Engine

• Place a floor jack rated 3-ton minimum under the engine oil pan with a wide wood block between the jack and pan.
• Lift only enough to support the engine weight. Do not raise the vehicle from the oil pan.
• If using an engine support bar, install it across the strut towers and attach it to a safe engine lifting point.

Step 7: Remove the Right-Side Engine Mount Area

• Use a 17mm socket and 19mm socket to remove the engine mount fasteners as needed for timing cover clearance.
• Keep the engine supported while these bolts are out.
• Mark mount positions with a paint marker before removal.
• During installation, tighten the engine mount fasteners securely to Toyota service specifications for your mount location.

Step 8: Remove the Crankshaft Pulley

• Install the crankshaft pulley holding tool (specialty) to keep the pulley from turning.
• Use a 22mm socket and 1/2-inch drive breaker bar to loosen the crankshaft pulley bolt.
• Use a harmonic balancer puller (specialty) to remove the crankshaft pulley.
• Do not pry against the timing cover with a screwdriver.

Step 9: Remove the Valve Cover

• Use a 10mm socket to remove ignition coil fasteners.
• Use a 10mm socket to remove valve cover bolts.
• Lift the valve cover straight up by hand.
• If stuck, gently work around the edge with a plastic trim clip removal tool. Do not gouge the aluminum surface.

Step 10: Set Engine to Top Dead Center

• Use a 22mm socket on the crankshaft bolt area to rotate the engine clockwise only.
• Align the crankshaft timing mark to top dead center.
• Confirm the camshaft timing marks line up with their reference marks.
• Use a paint marker to mark the old chain and sprocket positions before removal.
• Clockwise only prevents chain slack errors.

Step 11: Remove the Timing Cover

• Use 10mm socket, 12mm socket, and 14mm socket to remove all timing cover bolts.
• Note bolt lengths and locations. Some bolts are different lengths.
• Use a plastic razor tool to break the old sealant edge carefully.
• Remove the timing cover straight forward.
• Do not damage the aluminum sealing surfaces.

Step 12: Remove the Timing Chain Tensioner and Guides

• Use a 10mm socket to remove the timing chain tensioner bolts.
• Use a 10mm socket and 12mm socket to remove timing chain guide bolts.
• Remove the chain guides by hand.
• Keep light tension on the chain while removing parts so it does not jump teeth.

Step 13: Remove the Timing Chain

• Slide the timing chain off the camshaft and crankshaft sprockets by hand.
• Compare the old chain to the new chain on a clean surface.
• Do not rotate the crankshaft or camshafts after the chain is removed.

Step 14: Install the New Timing Chain

• Align the colored links on the new timing chain with the timing marks on the camshaft sprockets and crankshaft sprocket.
• Use your paint marker marks as an extra visual check, not as the only reference.
• Install the chain fully onto each sprocket by hand.
• Verify all timing marks match before installing the guides.

Step 15: Install New Guides and Tensioner

• Use a 10mm socket and 12mm socket to install the new timing chain guides.
• Tighten guide bolts evenly. Torque to Toyota service specification for each guide bolt size.
• Install the new timing chain tensioner using a 10mm socket.
• Release the tensioner pin only after the chain and guides are correctly installed.
• Confirm the chain is tight on the drive side and tensioned on the guide side.

Step 16: Rotate Engine by Hand and Recheck Timing

• Use a 22mm socket and 1/2-inch drive breaker bar to rotate the crankshaft clockwise two full turns.
• Stop at top dead center again.
• Recheck the camshaft and crankshaft timing marks.
• If marks do not line up correctly, remove the tensioner and reset the chain before continuing.
• Use a feeler gauge set only if checking related clearances during deeper inspection.

Step 17: Clean Timing Cover Sealing Surfaces

• Use a plastic razor tool to remove old sealant from the timing cover and engine block.
• Use brake cleaner spray and shop towels to clean oil from the sealing surfaces.
• Surfaces must be dry before sealant is applied.
• Do not use metal scrapers on aluminum sealing surfaces.

Step 18: Replace the Front Crankshaft Seal

• Use a flat-blade screwdriver carefully to remove the old crankshaft front oil seal from the timing cover.
• Press the new seal in squarely using a suitable large socket from the metric socket set 8mm-22mm.
• Make sure the seal sits flush and even.

Step 19: Reinstall the Timing Cover

• Apply timing cover sealant in the correct bead pattern around the timing cover sealing surface.
• Install the timing cover within the sealant working time.
• Use 10mm socket, 12mm socket, and 14mm socket to install bolts in their original locations.
• Tighten bolts gradually in an even pattern. Torque to Toyota service specification by bolt size and location.
• Even tightening prevents oil leaks.

Step 20: Reinstall the Valve Cover

• Install the new valve cover gasket set into the valve cover groove.
• Use brake cleaner spray and shop towels to clean the cylinder head sealing surface.
• Set the valve cover in place by hand.
• Use a 10mm socket to install valve cover bolts.
• Tighten evenly. Torque to 10 Nm (89 in-lbs).

Step 21: Reinstall Crankshaft Pulley

• Slide the crankshaft pulley onto the crankshaft by hand, aligning the keyway correctly.
• Use the crankshaft pulley holding tool (specialty) to hold the pulley.
• Use a 22mm socket and 1/2-inch drive torque wrench to tighten the crankshaft pulley bolt.
• Torque to Toyota service specification for the 2.7L crankshaft pulley bolt.

Step 22: Reinstall Engine Mount and Brackets

• Use a 17mm socket and 19mm socket to reinstall engine mount fasteners.
• Lower the engine support slowly with the floor jack rated 3-ton minimum.
• Use your paint marker alignment marks to position the mount correctly.
• Tighten mount fasteners securely to Toyota service specifications.

Step 23: Reinstall Accessory Belt and Removed Components

• Use a 14mm socket or wrench to rotate the belt tensioner.
• Route the belt over the pulleys using your photo or routing diagram.
• Release the tensioner slowly.
• Use 10mm socket, 12mm socket, and 14mm socket to reinstall brackets, retainers, and accessories.
• Make sure the belt ribs sit fully in every pulley groove.

Step 24: Refill Oil and Coolant

• Install a new oil filter using the correct oil filter tool if needed.
• Refill with the correct amount of engine oil.
• Refill the cooling system with Toyota-compatible coolant.
• Use shop towels to wipe any spilled oil or coolant.

Step 25: Reconnect Battery and First Start

• Use a 10mm socket to reconnect the negative battery terminal.
• Before starting, verify no tools are left in the engine bay.
• Start the engine and let it idle.
• Listen for chain rattle, knocking, or abnormal noises.
• Shut the engine off immediately if it runs rough or makes loud mechanical noise.

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✅ After Repair

• ✅ Check around the timing cover, valve cover, oil filter, and drain plug for leaks.
• ✅ Let the engine reach operating temperature and confirm the cooling fans cycle normally.
• ✅ Top off coolant after air bubbles purge from the system.
• ✅ Recheck engine oil level after the engine has been off for several minutes.
• ✅ Road test gently for 10-15 minutes, then inspect again for leaks.
• ✅ If the check engine light comes on, scan for codes before continuing to drive.

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💰 DIY vs Shop Cost

Shop Cost: $1,800-$3,200 USD equivalent (parts + labor)

DIY Cost: $350-$750 USD equivalent (parts only)

You Save: $1,100-$2,450 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 8-12 hours.

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