🔧 Prius - Radiator Hose Replacement

Assumption: You want to replace the engine coolant radiator hose(s) (upper and/or lower).

This job replaces a leaking/soft/bulging radiator hose that carries engine coolant between the engine and radiator. You’ll drain some coolant, swap the hose and clamps, then refill and bleed air so the engine doesn’t overheat.

Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cold engine; hot coolant can cause severe burns.
• ⚠️ Hybrid caution: avoid touching any orange high-voltage cables or components.
• ⚠️ Support the car with jack stands; never rely on a jack alone.
• ⚠️ Keep coolant off belts and electrical connectors; wipe spills immediately.
• ⚠️ Battery disconnect is not required for this job, but keep the key fob away from the car so it can’t power on unexpectedly.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 2-ton minimum)
• Jack stands (rated 2-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Drain pan (at least 2-gallon)
• 10mm socket
• 3/8" drive ratchet
• 6" socket extension
• Flathead screwdriver
• Hose clamp pliers (specialty)
• Pick tool (small hook)
• Coolant funnel kit (spill-free style)
• Trim clip removal tool
• Shop rags
• 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 - Qty: 1-2 gallons

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📋 Before You Begin

• Park on level ground, shift to P, and set the parking brake.
• Let the engine cool completely (best: sit overnight).
• Open the hood and remove the radiator cap/pressure cap only when cold (it should turn easily).
• Plan for coolant cleanup: keep pets/kids away (coolant is toxic and tastes sweet).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise the front of the car safely

• Place wheel chocks behind the rear wheels.
• Lift the front using the floor jack at the front center jacking point.
• Set the car down onto jack stands at the proper front support points.

Step 2: Remove the front engine under cover (splash shield)

• Use a 10mm socket, ratchet, and extension to remove the bolts.
• Use a trim clip removal tool to pop out any plastic clips.
• Set hardware aside in a small tray so it doesn’t get lost.

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

• Place a drain pan under the radiator drain (lower area of the radiator).
• Open the drain carefully using a flathead screwdriver if needed (some drains are hand-turn; use the tool only if it’s tight).
• Drain until the coolant level is below the hose you’re replacing, then close the drain snug (do not overtighten).
• Tip: Drain less = less mess later.

Step 4: Remove the radiator hose clamp(s)

• Identify the hose you’re replacing:
• Upper hose: runs from the top of the radiator to the engine side.
• Lower hose: runs from the bottom of the radiator to the engine side (usually accessed best from below).
• Use hose clamp pliers (specialty) to squeeze the clamp and slide it back on the hose.
• Hose clamp pliers lock the clamp open.

Step 5: Break the hose loose and remove it

• Twist the hose by hand to break it free. If it’s stuck, use a pick tool to gently lift the hose edge and let air in.
• Pull the hose off the fitting while holding a shop rag under it for drips.
• If coolant spills, wipe it up immediately with shop rags.
• Do not pry hard on plastic radiator necks.

Step 6: Install the new hose and clamps

• Compare the new hose to the old hose (same shape and length).
• Slide new radiator hose clamps onto the hose first.
• Push the hose fully onto the radiator/engine fittings until it seats against the stop/bead.
• Use hose clamp pliers (specialty) to position the clamp in the same spot as the original (behind the raised bead on the fitting).

Step 7: Reinstall the under cover

• Reinstall clips using the trim clip removal tool as needed to align them.
• Reinstall bolts using the 10mm socket, ratchet, and extension and tighten them snug.

Step 8: Refill coolant

• Install a coolant funnel kit (spill-free style) at the radiator/pressure fill point (where applicable) and slowly add Toyota Super Long Life Coolant (pink) premixed.
• Fill to the correct level and also fill the overflow reservoir to the appropriate mark.

Step 9: Bleed air and verify heater operation (Prius engine run/inspection mode)

• Set cabin heat to MAX HOT so coolant flows through the heater core.
• To enter engine run/inspection mode (so the engine keeps running):
• Press the Power button twice without pressing the brake (dash ON).
• Press the accelerator two times.
• Shift to N, press accelerator two times.
• Shift to P, press accelerator two times.
• Now press brake and press Power to start (engine should run more continuously).
• Watch coolant level in the funnel; add coolant as bubbles purge.
• Use a flashlight to inspect both hose ends for leaks while running.
• Once bubbles slow and the heater blows hot, shut the car off and let it cool, then top off as needed.

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✅ After Repair

• Check for leaks around both hose ends with the engine running and after a full cool-down.
• Recheck coolant level in the reservoir the next day (cold) and top off with Toyota Super Long Life Coolant (pink) premixed if needed.
• If you see overheating, gurgling, or no cabin heat, stop driving and re-bleed (air is still trapped).
• Dispose of old coolant properly (sealed container; take to a recycling center).

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💰 DIY vs Shop Cost

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

DIY Cost: $60-$160 (parts only)

You Save: $190-$390 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.

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🎯 Ready to get started?

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