🔧 RX350 - Radiator Hose Replacement

Your RX350 has two main radiator hoses: the upper hose (top of radiator to engine) and the lower hose (bottom of radiator to engine). Replacing a hose is mostly about safely draining some coolant, swapping the hose/clamps, then refilling and bleeding air so it doesn’t overheat.

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

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⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap when hot; coolant can spray and burn.
• ⚠️ Support the vehicle with jack stands if you go underneath; never rely on a jack.
• ⚠️ Coolant is toxic to people and pets; catch it in a drain pan and clean spills.
• ⚠️ Keep fingers clear of the cooling fans; they can turn on unexpectedly.
• ⚠️ 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 10-quart)
• Spill-free funnel kit (specialty)
• Hose clamp pliers (specialty)
• Channel-lock pliers
• Pick tool
• Flathead screwdriver
• 10mm socket
• 3/8" drive ratchet
• 6" socket extension
• Trim clip removal tool
• Shop towels
• Torque wrench (10-80 Nm range)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Radiator hose (upper) - Qty: 1
• Radiator hose (lower) - Qty: 1
• Hose clamps - Qty: 2
• Toyota/Lexus Super Long Life Coolant (pink, pre-mixed) - Qty: 1-2 gallons

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📋 Before You Begin

• 🧰 Park on level ground, set the parking brake, and let the engine cool fully.
• 🧰 Set the HVAC to MAX HEAT later during bleeding (this helps move coolant through the heater circuit).
• 🧰 Place a drain pan under the radiator area before loosening anything.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove covers for access

• Open the hood and remove the plastic engine cover by pulling it upward with your hands (no tools).
• If you need more room at the top hose area, loosen the intake duct clamps using a flathead screwdriver and move the duct aside.
• If you’re doing the lower hose, raise the front with a floor jack (rated 3-ton minimum), set it on jack stands (rated 3-ton minimum), and remove any underbody splash shield fasteners using a 10mm socket, 3/8" drive ratchet, 6" socket extension, and trim clip removal tool.

Step 2: Relieve pressure safely

• Place a shop towel over the radiator cap area and slowly loosen the cap only if the system is stone cold.
• If you feel pressure or hear hissing, tighten it back and wait longer.

Step 3: Drain enough coolant to get below the hose level

• Position the drain pan (at least 10-quart) under the radiator drain area.
• Open the radiator drain cock (if accessible) by turning it gently by hand or with a flathead screwdriver as needed.
• Drain until coolant level is below the hose you’re replacing, then close the drain cock snugly by hand. Don’t overtighten plastic drains.

Step 4: Remove the hose clamps

• Use hose clamp pliers (specialty) to compress spring-style clamps (these are the factory “pinch” clamps) and slide the clamp back on the hose.
• If your hose has screw-style clamps, loosen them with a flathead screwdriver and slide them back.

Step 5: Remove the old radiator hose

• Twist the hose back and forth by hand to break it free.
• If it’s stuck, carefully work the edge loose with a pick tool (avoid gouging the radiator/engine fitting).
• Pull the hose off and aim it into the drain pan (at least 10-quart) to catch remaining coolant.

Step 6: Prep the fittings and install the new hose

• Wipe the radiator/engine hose necks clean using shop towels.
• Slide the clamps onto the new hose before installing the hose.
• Push the new hose fully onto the fittings until it bottoms out.
• Reposition the clamps to the same spot as the original (usually just behind the raised “bead” on the fitting) using hose clamp pliers (specialty) or a flathead screwdriver for screw clamps.

Step 7: Reinstall intake pieces and under covers

• Reinstall the intake duct and tighten clamps using a flathead screwdriver.
• Reinstall the splash shield using a 10mm socket, 3/8" drive ratchet, 6" socket extension, and trim clip removal tool.
• If you removed bolts, tighten them with a torque wrench (10-80 Nm range) to snug (small fasteners). Do not overtighten plastic shields.

Step 8: Refill coolant

• Install a spill-free funnel kit (specialty) at the radiator fill point (or reservoir fill point if that’s your accessible fill).
• Pour in Toyota/Lexus Super Long Life Coolant (pink, pre-mixed) until the level stabilizes.
• Set the reservoir to the FULL line as well.

Step 9: Bleed air and verify operation

• Start the engine and let it idle with the heater set to hot.
• Watch the funnel level; add coolant as air burps out.
• Once the engine warms up, confirm the upper hose gets hot (thermostat opening) and you have steady cabin heat.
• Shut the engine off, let it cool, then recheck and top off coolant as needed using the spill-free funnel kit (specialty).

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✅ After Repair

• 🧪 Check for leaks around both ends of the replaced hose while idling and again after a short test drive.
• 🧪 Recheck coolant level the next morning (cold engine) and top off if needed.
• 🧪 If the temperature gauge rises, heater blows cold, or you hear gurgling, shut it down and re-bleed air using the spill-free funnel kit (specialty).

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💰 DIY vs Shop Cost

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

DIY Cost: $50-$180 (parts only)

You Save: $200-$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?

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