🔧 Impreza - Radiator Hose Replacement

Replacing a radiator hose means draining some coolant, removing the old hose and clamps, then installing the new hose and refilling/bleeding the cooling system. A bad hose can leak or burst and quickly cause overheating, so it’s a smart preventative repair if the hose is swollen, cracked, or seeping.

Difficulty Level: Beginner | 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 cause severe burns.
• ⚠️ Support the car with jack stands; never rely on a floor jack alone.
• ⚠️ Keep coolant off belts and electrical connectors; wipe spills immediately.
• ⚠️ Coolant is toxic to pets; collect and dispose of it properly.

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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)
• Funnel
• Pliers
• Hose clamp pliers (specialty)
• Flathead screwdriver
• Pick tool
• Trim clip tool
• 10mm socket
• 3/8" ratchet
• 3" extension
• Torque wrench (3/8" drive)
• 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
• Radiator hose clamps - Qty: 4
• Subaru-approved coolant (blue long-life premix) - Qty: 2 gallons

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Let the engine cool fully (upper radiator hose should feel cool, not warm).
• Remove the engine under cover if equipped (fasteners vary; use 10mm socket and trim clip tool).
• Take a photo of hose routing first.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Relieve any leftover pressure safely

• Use a shop rag over the radiator cap, then slowly loosen it only if the engine is completely cool.
• If you hear pressure release, pause until it stops, then remove the cap.

Step 2: Raise the front (helps access the lower hose)

• Use a floor jack (rated 3-ton minimum) to lift the front jacking point.
• Set the car onto jack stands (rated 3-ton minimum) and keep wheel chocks in place.

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

• Place a drain pan (at least 10-quart) under the radiator drain area.
• Open the radiator drain cock (plastic drain valve) by hand; if access is tight, use pliers gently.
• Drain until the coolant level is below the hose you’re replacing, then close the drain cock.
• Torque: No published torque (plastic drain cock); tighten by hand until snug. Overtightening can crack it.

Step 4: Remove the upper radiator hose (radiator to engine)

• Use hose clamp pliers (specialty) to squeeze the spring clamp and slide it back on the hose.
• Repeat for the clamp at the other end of the hose.
• Twist the hose to break it free. If stuck, use a pick tool to gently separate the hose from the fitting. (A pick tool is a small hooked tool used to break seals without prying hard.)
• Pull the hose off both ends and guide it out.

Step 5: Remove the lower radiator hose (radiator to engine)

• Make sure the drain pan is positioned under the lower hose; extra coolant will spill.
• Use hose clamp pliers (specialty) to move the spring clamps back from the ends.
• Twist and remove the hose. Use the pick tool carefully if it’s bonded to the fitting.

Step 6: Prep the fittings and compare parts

• Wipe the radiator and engine hose fittings clean with shop rags.
• Compare the new hose(s) to the old hose(s) for length, bends, and diameter.
• If your replacement includes new clamps, place them onto the hose now.

Step 7: Install the new hose(s) and clamps

• Push the new hose fully onto each fitting until it bottoms out against the stop bead.
• Use hose clamp pliers (specialty) to position spring clamps in the same area as factory (behind the raised bead on the fitting).
• Torque: No torque spec (spring clamps); verify the clamp is centered and fully seated.
• If using screw-type clamps, tighten with a flathead screwdriver until snug, then stop. Too tight can cut the hose.

Step 8: Reinstall under cover (if removed)

• Reinstall the splash shield/under cover using a 10mm socket, 3/8" ratchet, and trim clip tool as needed.
• Torque: No critical torque (plastic clips/10mm shield bolts); snug only.

Step 9: Refill coolant and bleed air

• Use a funnel and refill the radiator with Subaru-approved coolant (blue long-life premix).
• Fill the coolant reservoir to the “FULL” line.
• Start the engine and set the HVAC to full hot, fan on low.
• Let the engine idle and warm up; watch for bubbles and falling coolant level, and top off as needed using the funnel.
• When the radiator fan cycles on/off and heat blows hot, install the radiator cap.

Step 10: Check for leaks

• With the engine running, inspect both ends of each replaced hose using safety glasses and a flashlight (use your phone light if needed).
• Shut the engine off, let it cool, then recheck the reservoir level and top off if needed.

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✅ After Repair

• Do a short test drive, then recheck for seepage around hose ends.
• After the engine cools completely (later that day or next morning), recheck coolant level in the reservoir and top off.
• If you notice gurgling behind the dash or temperature swings, air may still be trapped; repeat the bleed/top-off process.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $60-$140 (parts only)

You Save: $190-$310 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.