🔧 Highlander - Radiator Hose Replacement

This repair replaces a cracked, leaking, swollen, or soft radiator hose on your Highlander. The upper hose is usually easier; the lower hose drains more coolant and may be tighter to reach.

Difficulty Level: Beginner | Estimated Time: 1-2 hours

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⚠️ Safety & Precautions

• ⚠️ Work only when the engine is completely cool. Hot coolant can spray out and burn you.
• ⚠️ Never remove the radiator cap or reservoir cap while the engine is hot.
• ⚠️ Coolant is poisonous. Keep it away from children and pets.
• ⚠️ Wipe spilled coolant right away because it is slippery.
• ⚠️ Battery disconnect is not required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Drain pan 2-gallon minimum
• 10mm socket
• 3/8-inch ratchet
• Flat-blade screwdriver 6-inch
• Hose clamp pliers 45-degree (specialty)
• Slip-joint pliers 10-inch
• Plastic trim clip remover
• Long-neck funnel
• Coolant spill-free funnel kit (specialty)
• Clean shop towels
• Torque wrench inch-pound 1/4-inch drive

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Radiator hose - Qty: 1
• Radiator hose clamps - Qty: 2
• Toyota Super Long Life Coolant 50/50 premix - Qty: 1-2 gallons
• Radiator drain plug gasket - Qty: 1

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📋 Before You Begin

• Park your Highlander on level ground and set the parking brake.
• Let the engine cool for at least 2-3 hours.
• A hose clamp is the metal band that squeezes the hose tight so coolant cannot leak.
• A spill-free funnel locks onto the radiator opening and helps trapped air escape while you refill coolant.
• Take a photo of the hose routing and clamp positions before removing anything.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Confirm the Engine Is Cool

• Put on safety glasses and nitrile gloves.
• Touch the radiator hose carefully by hand. It must feel cool.
• Slowly remove the radiator cap by hand only after the engine is fully cool.
• Cool first, repair second.

Step 2: Remove Access Covers if Needed

• Use a 10mm socket and 3/8-inch ratchet to remove any small cover bolts blocking the hose.
• Use a plastic trim clip remover to remove any plastic push clips.
• Set the clips and bolts in a small safe spot.

Step 3: Drain Some Coolant

• Place the drain pan 2-gallon minimum under the radiator drain area.
• Open the radiator drain plug by hand. If it is tight, gently use slip-joint pliers 10-inch.
• Drain coolant until the level is below the hose you are replacing.
• For the upper hose, drain about 1 gallon.
• For the lower hose, expect more coolant to drain.
• Close the drain plug by hand.
• If the drain plug uses a small bolt-style plug, use a 10mm socket and torque wrench inch-pound 1/4-inch drive. Torque to 2 Nm (18 in-lbs).
• Plastic drain plugs break easily.

Step 4: Move the Hose Clamps Back

• Use hose clamp pliers 45-degree to squeeze the spring clamp tabs together.
• Slide each clamp back onto the hose, away from the radiator and engine fittings.
• If screw clamps are installed, use a flat-blade screwdriver 6-inch to loosen them.

Step 5: Remove the Old Hose

• Twist the hose by hand to break it loose.
• If the hose is stuck, carefully use a flat-blade screwdriver 6-inch to loosen the edge of the hose.
• Do not pry hard on the plastic radiator neck.
• Pull the hose off and aim any remaining coolant into the drain pan 2-gallon minimum.

Step 6: Clean the Hose Connections

• Use clean shop towels to wipe the radiator and engine hose fittings clean.
• Check that no old rubber, dirt, or dried coolant is stuck on the fittings.
• Look closely for cracks on the radiator plastic neck.
• Clean fittings seal better.

Step 7: Install the New Hose

• Compare the new radiator hose to the old one before installing it.
• Slide the radiator hose clamps onto the new hose first.
• Push the hose fully onto the radiator fitting and engine fitting by hand.
• Use hose clamp pliers 45-degree to move the spring clamps into their original positions.
• Place each clamp behind the raised bead on the fitting.
• If using screw-style clamps, tighten with a flat-blade screwdriver 6-inch. Torque to 3-4 Nm (27-35 in-lbs).
• Do not overtighten clamps.

Step 8: Refill the Cooling System

• Install the coolant spill-free funnel kit on the radiator fill neck.
• If you do not have that kit, use a long-neck funnel.
• Slowly pour in Toyota Super Long Life Coolant 50/50 premix until the radiator is full.
• Fill the coolant reservoir to the “FULL” mark.
• Squeeze the new hose gently by hand a few times to help move air out.

Step 9: Bleed Air from the Cooling System

• Keep the coolant spill-free funnel kit installed if available.
• Start the engine and let it idle.
• Set the heater to full hot and the fan to low using the climate controls.
• Watch the funnel and add coolant as the level drops.
• Wait until air bubbles slow down and warm air blows from the heater.
• Install the radiator cap by hand once the coolant level stays steady.
• Stay clear of the cooling fan.

Step 10: Reinstall Covers

• Use the 10mm socket and 3/8-inch ratchet to reinstall any removed covers.
• Use the plastic trim clip remover only if you need help lining up clips.
• For small 10mm cover bolts, tighten gently. Torque to 5 Nm (44 in-lbs).

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✅ After Repair

• ✅ Let your Highlander idle and inspect both hose ends for leaks.
• ✅ Take a short drive while watching the temperature gauge.
• ✅ After the engine cools completely, recheck the radiator and reservoir levels.
• ✅ Top off only with Toyota Super Long Life Coolant 50/50 premix.
• ✅ Recheck for leaks the next day.

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💰 DIY vs Shop Cost

Shop Cost: $180-$350 (parts + labor)

DIY Cost: $35-$120 (parts only)

You Save: $145-$230 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.5 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.