🔧 Impreza - Radiator Hose Replacement

Your radiator hoses carry coolant between the engine and radiator. If a hose is leaking, swollen, cracked, or the clamp area is wet, replacing the hose(s) prevents overheating and engine damage.

Difficulty Level: Intermediate | Estimated Time: 1-2 hours

Assumption: stock hoses/clamps and factory-type coolant fill.

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⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap hot; coolant can spray and burn.
• ⚠️ Support the car with jack stands if you raise it; never rely on a jack.
• ⚠️ Keep coolant off belts and electrical connectors; wipe spills immediately.
• ⚠️ Dispose of old coolant properly; it’s toxic to people and pets.
• 🔋 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 2-ton minimum)
• Jack stands (rated 2-ton minimum)
• Wheel chocks
• Drain pan (at least 10-quart)
• Funnel (spill-free style)
• Hose clamp pliers (specialty)
• Slip-joint pliers
• Pick tool (small hook pick)
• Flathead screwdriver
• Trim clip remover
• 10mm socket
• 3/8" ratchet
• 3/8" torque wrench
• 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
• Engine coolant (Subaru long-life premix equivalent) - Qty: 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 completely (ideally several hours).
• Set the cabin heat to HOT and fan to LOW (this helps coolant flow during bleeding).
• If you need access from below, lift 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: Remove the radiator cap (only when cold)

• Use a shop rag over the cap, then slowly turn the radiator cap to the first stop to release any leftover pressure.
• Remove the cap fully once no hissing is heard.

Step 2: Drain enough coolant to get below hose level

• Place a drain pan (10-quart) under the radiator.
• If your Impreza has an undertray, remove clips/bolts using a trim clip remover and 10mm socket.
• Open the radiator drain cock (small drain valve) by hand; use a flashlight to locate it.
• Drain until the coolant level is below the lower hose connection, then close the drain cock snugly by hand.
• Tip: save clean coolant only if new.

Step 3: Remove the upper radiator hose

• Locate the upper hose (top of radiator to the engine).
• Use hose clamp pliers (specialty) to squeeze the spring clamp and slide it back on the hose.
• Twist the hose to break it loose. If it’s stuck, gently work a pick tool (small hook pick) between the hose and fitting to release the seal.
• Pull the hose off. Catch drips with the drain pan and shop rags.
• Tip: don’t pry hard on plastic fittings.

Step 4: Remove the lower radiator hose

• Locate the lower hose (bottom of radiator to the engine).
• Use hose clamp pliers (specialty) to move both clamps away from the ends.
• Twist and remove the hose. More coolant will drain—keep the drain pan positioned underneath.

Step 5: Install the new hoses and clamps

• Compare old and new hoses to ensure matching shape and diameter.
• Install new clamps onto each hose before fitting the hose onto the car.
• Push the hose fully onto each fitting until it bottoms out (fully seated).
• Position the clamps behind the raised “bead” on the fitting (the bump that helps prevent leaks), then release using hose clamp pliers (specialty).

Step 6: Reinstall the undertray (if removed)

• Reinstall clips/bolts using a trim clip remover and 10mm socket.

Step 7: Refill coolant

• Use a funnel (spill-free style) and slowly fill the radiator with engine coolant (Subaru long-life premix equivalent) until full.
• Fill the overflow reservoir to the FULL line.
• Reinstall the radiator cap.

Step 8: Bleed air from the cooling system

• Start the engine and let it idle.
• Set the heater to HOT and fan to LOW.
• Watch temperature and look for leaks at both hose ends using a flashlight.
• After a few minutes, shut the engine off and let it cool, then carefully remove the radiator cap and top off as needed using the funnel (spill-free style).
• Repeat once if the level drops again after cooling.
• Tip: gently squeeze upper hose to burp air.

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✅ After Repair

• Check for leaks with the engine running and again after your first short drive.
• Verify the cabin heater blows hot air (a cold heater can mean trapped air).
• After the engine cools fully, recheck the radiator level and reservoir level and top off if needed.
• Monitor the temperature gauge for the next few trips.

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💰 DIY vs Shop Cost

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

DIY Cost: $40-$120 (parts only)

You Save: $130-$410 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1-2 hours.

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🎯 Ready to get started?

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