🔧 Highlander - Radiator Hose Replacement

Replacing a radiator hose stops coolant leaks and prevents overheating. On your Highlander, you may have an upper hose (radiator to engine) and a lower hose (radiator to engine/water pump area); the lower one is usually tighter to access.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.5 hours

Assumption: replacing both upper and lower hoses.

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⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap on a hot engine; hot coolant can spray and burn.
• ⚠️ Support the vehicle with jack stands before going underneath.
• ⚠️ Coolant is toxic; keep it away from kids and pets and clean spills right away.
• ⚠️ Use only Toyota-compatible coolant; mixing types can cause gel/sludge.
• 🔋 Battery disconnect is not required for this job.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Drain pan (at least 2-gallon)
• Funnel
• Hose clamp pliers
• Slip-joint pliers
• Pick tool (small) (specialty)
• Flathead screwdriver
• 10mm socket
• Ratchet (3/8" drive)
• Extension (3/8" drive, 6")
• Trim clip removal tool
• Shop towels
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Upper radiator hose - Qty: 1
• Lower radiator hose - Qty: 1
• Radiator hose clamps - Qty: 4
• Toyota Super Long Life Coolant (pink, premixed 50/50) - Qty: 1-2 gallons

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📋 Before You Begin

• Park on level ground, set the parking brake, and place wheel chocks behind the rear wheels.
• Let the engine cool fully (best: sit overnight).
• Set the heater to HOT later during bleeding so coolant can flow through the heater core (the small radiator inside the dash).
• If you plan to replace the lower hose, raise the front and support with jack stands.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the lower splash shield (for lower hose access)

• Raise the front with a floor jack and place jack stands under safe lift points.
• Use a trim clip removal tool and 10mm socket with a ratchet to remove the clips/bolts holding the front lower splash shield.
• Set the shield and fasteners aside.

Step 2: Relieve pressure (engine cold)

• Place shop towels around the radiator cap area.
• Slowly loosen the radiator cap by hand to the first stop, then remove it fully once you’re sure there’s no pressure.

Step 3: Drain enough coolant to get below the hoses

• Place a drain pan under the radiator drain.
• Use a flathead screwdriver to open the radiator drain cock (small drain valve) slowly and drain coolant until the level is below the upper/lower hose connections.
• Close the drain cock by hand using the flathead screwdriver (snug only). Don’t overtighten plastic drains.

Step 4: Remove the upper radiator hose

• Use hose clamp pliers to compress the spring clamp, then slide it back a few inches on the hose.
• Twist the hose by hand to break it free. If it’s stuck, gently work the edge loose with a pick tool (small) (specialty) (a pick is a small hooked tool used to separate stuck rubber without tearing it).
• Pull the hose off the radiator neck first, then off the engine-side fitting. Catch any remaining coolant with the drain pan and shop towels.

Step 5: Remove the lower radiator hose

• From underneath, use a flashlight to locate the lower hose and both clamps.
• Use hose clamp pliers (or slip-joint pliers if needed) to move the clamps back on the hose.
• Twist the hose to break it free, then remove it. Use the pick tool (small) (specialty) carefully if it’s stuck.

Step 6: Clean the hose sealing surfaces

• Use shop towels to wipe the radiator neck and engine-side fittings clean.
• If there’s crusty buildup, wipe firmly until smooth. Clean metal helps prevent leaks.

Step 7: Install the new lower radiator hose

• Slide the clamps onto the new hose first.
• Push the hose fully onto each fitting until it bottoms out (no gap).
• Use hose clamp pliers to move each clamp into position: it should sit behind the raised “bead” on the fitting.
• Torque: Spring clamps have no torque spec; make sure they are centered and fully seated.

Step 8: Install the new upper radiator hose

• Slide the clamps onto the new hose.
• Push the hose fully onto the radiator and engine fittings.
• Use hose clamp pliers to position the clamps behind the bead on each fitting.
• Torque: Spring clamps have no torque spec; correct placement is what matters.

Step 9: Refill coolant

• Insert a funnel into the radiator fill neck.
• Pour in Toyota Super Long Life Coolant (pink, premixed 50/50) slowly until full.
• Fill the coolant reservoir to the FULL line.

Step 10: Bleed air from the cooling system

• Start the engine and let it idle with the radiator cap off.
• Set the cabin heat to HOT and fan to LOW.
• Watch the coolant level at the radiator neck and add coolant as the level drops.
• When the engine warms up, you should see flow and occasional air bubbles; keep topping off as needed.
• Once bubbles reduce and the level stabilizes, install the radiator cap by hand.

Step 11: Reinstall the splash shield

• Reinstall the lower splash shield using the trim clip removal tool and 10mm socket with a ratchet.
• Remove the jack stands and lower the vehicle using the floor jack.

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✅ After Repair

• With the engine running, inspect both hoses for seepage at the clamps using a flashlight.
• Take a 10-15 minute drive, then park and re-check for leaks.
• After the engine fully cools, re-check the reservoir level and top off to FULL using Toyota Super Long Life Coolant (pink, premixed 50/50).
• If the heater blows cold or the temp gauge rises, shut off and re-bleed (air is still trapped).

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💰 DIY vs Shop Cost

Shop Cost: $250-$600 (parts + labor)

DIY Cost: $60-$180 (parts only)

You Save: $190-$420 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-2.0 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.