🔧 4Runner - Radiator Hose Replacement

Replacing a radiator hose stops coolant leaks and prevents overheating. On your 4Runner, you may be replacing the upper hose (radiator to engine) or the lower hose (radiator to engine/water inlet). The job is similar for both—just expect tighter access on the lower hose.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap on a hot engine; hot coolant can burn you.
• ⚠️ Support the 4Runner with jack stands if you raise it—never rely on a jack alone.
• ⚠️ Keep coolant off the ground; it’s toxic and attractive to pets.
• ⚠️ If the cooling fan runs unexpectedly, keep hands clear; remove the key and keep it out of the vehicle.
• 🔋 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 (at least 3-gallon)
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Pliers (hose clamp pliers) (specialty)
• Channel-lock pliers
• Pick tool (hook pick) (specialty)
• Flat blade screwdriver
• 10mm socket
• Ratchet (3/8" drive)
• Torque wrench (10–80 ft-lbs)
• Funnel
• Shop rags

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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
• Hose clamps (OEM-style spring clamps or worm-gear clamps) - Qty: 2
• Toyota Super Long Life Coolant (pink) 50/50 premix - 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 (ideally sit for 2+ hours).
• Set your HVAC to HEAT (this helps coolant circulate through the heater core during bleeding later).
• If doing the lower hose, raise the front with a floor jack and support with jack stands.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Relieve pressure safely

• Place shop rags around the radiator cap.
• Slowly loosen the radiator cap to the first stop to release any remaining pressure, then remove it fully once no hissing is heard.

Step 2: Drain enough coolant to get below the hose level

• Position a drain pan under the radiator drain cock (petcock).
• Open the drain cock carefully by hand if possible; if tight, use a flat blade screwdriver gently.
• Drain until the coolant level is below the hose you’re replacing (usually 1–2 gallons for a lower hose, less for an upper hose).
• Close the drain cock snugly (do not over-tighten; it’s plastic on many radiators).

Step 3: Remove covers for access (as needed)

• If you need more room, remove the front lower splash shield bolts using a 10mm socket and ratchet.
• Keep fasteners organized on a rag or tray. Small bolts disappear fast.

Step 4: Remove the hose clamps

• Factory clamps are often spring clamps (a clamp you squeeze to open).
• Use pliers (hose clamp pliers) (specialty) or channel-lock pliers to squeeze the clamp tabs and slide the clamp back on the hose.
• If you have worm-gear clamps (screw type), loosen them with a flat blade screwdriver.

Step 5: Break the hose loose (don’t pry on the radiator neck)

• Twist the hose by hand to break the seal.
• If it’s stuck, slide a pick tool (hook pick) (specialty) gently under the hose end to let air in, then twist again.
• Pull the hose off. Aim the open end into the drain pan—some coolant will spill.

Step 6: Clean and inspect the fittings

• Wipe the radiator neck and engine-side fitting with shop rags.
• Make sure no old rubber is stuck on the fitting.
• Check the radiator neck for cracks. If cracked, don’t continue until it’s addressed.

Step 7: Install the new hose

• Slide the clamps onto the new hose before installing it.
• Push the hose on until it bottoms out against the stop bead on the fitting.
• Reposition the clamp over the fitting bead (not on the very end of the hose).
• For spring clamps, use pliers (hose clamp pliers) (specialty) to set it in place.
• For worm-gear clamps, tighten with a flat blade screwdriver until snug—do not crush the hose.

Step 8: Reinstall any shields/covers

• Reinstall the splash shield using a 10mm socket and ratchet.
• If you use a torque wrench on small 10mm bolts: Torque to 7 Nm (62 in-lbs) (snug is fine for most splash shield bolts).

Step 9: Refill coolant

• Insert a funnel into the radiator fill neck.
• Refill with Toyota Super Long Life Coolant (pink) 50/50 premix until the radiator is full.
• Fill the coolant reservoir to the FULL line.

Step 10: Bleed air from the cooling system

• Leave the radiator cap off.
• Start the engine and let it idle.
• Set the heater to HOT and fan to medium.
• Watch the coolant level; as the thermostat opens, the level may drop—add coolant as needed with the funnel.
• When you see a steady flow (fewer bubbles) and the upper hose warms up, install the radiator cap.
• Let the engine reach normal operating temperature, then shut it off and check for leaks.

Step 11: Top off after cool-down

• After the engine cools fully, recheck the reservoir level and add coolant if needed.
• Inspect both hose ends for any wetness.

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✅ After Repair

• Start the engine and verify the temperature gauge stays normal during a 10–15 minute drive.
• Park, let it idle 2 minutes, and recheck for leaks with a flashlight.
• Over the next 2–3 days, check the reservoir level each morning and top off if it drops.
• If you get overheating, no cabin heat, or gurgling sounds, shut it down—there may still be trapped air.

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💰 DIY vs Shop Cost

Shop Cost: $250-$550 (parts + labor)

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

You Save: $190-$370 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.