🔧 Highlander - Engine Mount Replacement

Replacing the engine mounts on your Highlander means supporting the engine safely, removing the worn mounts, and installing new ones in the same positions. Engine mounts hold the engine steady and reduce vibration; bad mounts can cause clunks, shaking, or harsh movement when shifting between Drive and Reverse.

Difficulty Level: Advanced | Estimated Time: 4-7 hours

Assumption: This guide covers the main engine/transaxle mount replacement procedure for your stock hybrid AWD setup.

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⚠️ Safety & Precautions

• ⚠️ Your Highlander is a full hybrid, so avoid orange high-voltage cables and hybrid components. Do not unplug or touch orange connectors.
• ⚠️ Disconnect the 12V battery negative cable before working near mounts, brackets, or wiring. This helps prevent accidental hybrid system wake-up.
• ⚠️ Never place any body part under the engine while it is supported only by a jack. Use a jack only to support and raise slightly, not to hold the vehicle.
• ⚠️ Support the engine with a wood block under the oil pan to spread the load. Do not lift directly against the bare oil pan with a metal jack pad.
• ⚠️ Work on a cool engine. Exhaust and cooling parts can stay hot for a long time.
• ⚠️ If any mount bracket bolts feel seized or cross-threaded, stop and reassess. Broken mount bolts can become a major repair.

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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
• 3/8-inch drive ratchet
• 1/2-inch drive ratchet
• 1/2-inch drive breaker bar
• 3/8-inch drive 6-inch extension
• 1/2-inch drive 6-inch extension
• 10mm wrench
• 12mm wrench
• 14mm wrench
• 17mm wrench
• 19mm wrench
• Torque wrench 10-150 ft-lb
• Trim clip removal tool
• Flat-blade screwdriver
• Floor jack 3-ton minimum
• Jack stands 3-ton minimum
• Wheel chocks
• Engine support bar 1,000-lb minimum (specialty)
• Wood block 12-inch minimum
• Paint marker
• Work light
• Mechanic gloves
• Safety glasses

A breaker bar is a long handle used to loosen tight bolts. An engine support bar is a beam that sits across the fenders and safely holds the engine from above.

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Right-side engine mount - Qty: 1
• Left-side transaxle mount - Qty: 1
• Front engine mount - Qty: 1
• Rear engine mount - Qty: 1
• Engine mount bracket bolts - Qty: As needed
• Plastic splash shield clips - Qty: As needed

Tip: Replace mounts as a set if several are cracked or oil-soaked. One weak mount can quickly stress the new one.

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📋 Before You Begin

• 🚗 Park your Highlander on level ground, shift to Park, set the parking brake, and chock the rear wheels.
• 🔋 Open the hood and disconnect the 12V battery negative cable with a 10mm wrench. The 12V battery powers control modules and relays.
• ❄️ Let the engine cool fully before working around the exhaust side and radiator area.
• 🖊️ Use a paint marker to mark each mount and bracket position before removal. This helps alignment during installation.
• 🧰 Only replace one mount at a time unless the engine is fully supported from above with an engine support bar.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and Secure the Vehicle

• Use wheel chocks behind the rear wheels.
• Use a floor jack 3-ton minimum at the front center jacking point to lift the front of your Highlander.
• Place jack stands 3-ton minimum under the front side support points.
• Gently lower the vehicle onto the jack stands and shake the vehicle lightly to confirm it is stable.
• Never work under an unsupported vehicle.

Step 2: Remove the Lower Engine Covers

• Put on safety glasses and mechanic gloves.
• Use a 10mm socket and 3/8-inch drive ratchet to remove lower splash shield bolts.
• Use a trim clip removal tool and flat-blade screwdriver to remove plastic clips.
• Remove the splash shield and set it aside.
• If clips break, replace them with plastic splash shield clips.

Step 3: Support the Engine

• Position the engine support bar 1,000-lb minimum across the upper fender support areas.
• Attach the support chain or hook to the engine lifting point.
• Turn the support bar adjuster by hand until it lightly holds engine weight.
• Place a wood block 12-inch minimum on the floor jack 3-ton minimum.
• Raise the jack until the wood block lightly touches the engine oil pan area. Do not lift the vehicle.
• Support the engine, do not jack it hard.

Step 4: Inspect and Mark Mount Positions

• Use a work light to inspect the right-side engine mount, left-side transaxle mount, front mount, and rear mount.
• Use a paint marker to mark bracket edges and bolt positions.
• Look for cracked rubber, separated rubber, collapsed height, or fluid leakage from hydraulic-style mounts.
• Replace the worst mount first if you are not replacing all four.

Step 5: Replace the Right-Side Engine Mount

• Use a 10mm socket and 3/8-inch drive ratchet to move any nearby wire retainers or small brackets attached to the mount area.
• Use a 17mm socket, 1/2-inch drive ratchet, and 1/2-inch drive 6-inch extension to loosen the mount-to-engine bracket fasteners.
• Use a 17mm socket or 19mm socket with a 1/2-inch drive breaker bar to loosen the mount-to-body fasteners.
• Raise or lower the engine slightly with the floor jack 3-ton minimum and wood block 12-inch minimum until the bolts slide out without binding.
• Remove the old right-side engine mount.
• Install the new right-side engine mount in the same orientation.
• Start all bolts by hand first. This prevents cross-threading.
• Use a 17mm socket or 19mm socket to snug the bolts, but do not fully tighten yet.
• Once the engine sits naturally on the mount, use a torque wrench 10-150 ft-lb to tighten mount-to-body bolts to Torque to 80 Nm (59 ft-lbs).
• Use the torque wrench 10-150 ft-lb to tighten mount-to-engine bracket bolts to Torque to 95 Nm (70 ft-lbs).

Step 6: Replace the Left-Side Transaxle Mount

• The transaxle is the transmission and front drive unit assembly.
• Support the transaxle side lightly with the floor jack 3-ton minimum and wood block 12-inch minimum.
• Use a 10mm socket and 3/8-inch drive ratchet to move any wire retainers or small brackets in the way.
• Use a 17mm socket, 19mm socket, and 1/2-inch drive breaker bar to loosen the mount fasteners.
• Adjust the jack height slightly until the bolts are not pinched.
• Remove the old left-side transaxle mount.
• Install the new left-side transaxle mount in the same orientation as the old one.
• Start all bolts by hand before using tools.
• Use a 17mm socket or 19mm socket to snug the bolts.
• Use a torque wrench 10-150 ft-lb to tighten mount-to-body bolts to Torque to 80 Nm (59 ft-lbs).
• Use the torque wrench 10-150 ft-lb to tighten bracket-to-transaxle bolts to Torque to 95 Nm (70 ft-lbs).

Step 7: Replace the Front Engine Mount

• Access the front mount from underneath near the lower front of the engine cradle.
• Use a 14mm socket or 17mm socket with a 3/8-inch drive ratchet to remove any small shields or brackets blocking access.
• Use a 17mm socket, 19mm socket, and 1/2-inch drive breaker bar to loosen the front mount through-bolt and mounting bolts.
• A through-bolt is the long bolt that passes through the center of the mount.
• Use the floor jack 3-ton minimum and wood block 12-inch minimum to adjust engine height until the through-bolt slides out smoothly.
• Remove the old front engine mount.
• Install the new front engine mount and start all fasteners by hand.
• Use a 17mm socket or 19mm socket to snug the bolts.
• Use a torque wrench 10-150 ft-lb to tighten front mount bracket bolts to Torque to 80 Nm (59 ft-lbs).
• Use the torque wrench 10-150 ft-lb to tighten the through-bolt to Torque to 95 Nm (70 ft-lbs).

Step 8: Replace the Rear Engine Mount

• The rear mount is the hardest mount to access and sits toward the firewall side of the powertrain.
• Use a work light to locate the rear mount and check the best tool angle before loosening bolts.
• Use a 17mm socket, 19mm socket, 1/2-inch drive 6-inch extension, and 1/2-inch drive breaker bar to loosen the rear mount fasteners.
• Use a 17mm wrench or 19mm wrench where a socket will not fit.
• Adjust the engine height very slightly with the floor jack 3-ton minimum and wood block 12-inch minimum until the through-bolt moves freely.
• Remove the old rear engine mount.
• Install the new rear engine mount in the same position.
• Start all fasteners by hand before tightening.
• Use a 17mm socket, 19mm socket, or matching wrench to snug the fasteners.
• Use a torque wrench 10-150 ft-lb to tighten rear mount bracket bolts to Torque to 80 Nm (59 ft-lbs).
• Use the torque wrench 10-150 ft-lb to tighten the rear mount through-bolt to Torque to 95 Nm (70 ft-lbs).
• Small engine height changes make bolt alignment easier.

Step 9: Settle the Engine and Final-Torque the Mounts

• Lower the floor jack 3-ton minimum slightly so the engine weight rests naturally on the new mounts.
• Lightly loosen, then re-torque any mount fastener that was tightened while the engine was raised.
• Use a torque wrench 10-150 ft-lb to verify each mount fastener is tightened to its specified torque.
• Check that no wiring, hoses, or hybrid-system components are pinched near any mount.

Step 10: Reinstall Covers and Lower the Vehicle

• Reinstall the lower splash shield with the original bolts and replacement clips as needed.
• Use a 10mm socket and 3/8-inch drive ratchet to tighten splash shield bolts until snug.
• Use the floor jack 3-ton minimum to lift the front slightly off the jack stands.
• Remove the jack stands 3-ton minimum.
• Lower your Highlander slowly to the ground.

Step 11: Reconnect the 12V Battery

• Reconnect the 12V battery negative cable.
• Use a 10mm wrench to tighten the terminal clamp until secure.
• Do not overtighten the battery terminal. It can crack.

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✅ After Repair

• ✅ Start your Highlander and let it idle. Expect the hybrid engine to cycle on and off normally.
• ✅ With your foot firmly on the brake, shift from Park to Reverse, then Drive, and listen for clunks.
• ✅ Check that vibration at idle is reduced and the engine does not jump excessively.
• ✅ Take a short, gentle test drive. Avoid hard acceleration until you confirm everything feels normal.
• ✅ Recheck visible mount bolts after the test drive with a torque wrench 10-150 ft-lb if access allows.
• ✅ If warning lights appear after the battery disconnect, drive normally for a short distance. Some systems may relearn. If lights remain, scan for codes.

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💰 DIY vs Shop Cost

Shop Cost: $900-$1,800 (parts + labor)

DIY Cost: $300-$850 (parts only)

You Save: $600-$950 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 4-7 hours.

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🎯 Ready to get started?

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