🔧 Forester - Radiator Hose Replacement

Replacing a radiator hose means safely draining some coolant, removing the old hose and clamps, and installing a new hose without leaks. On your Forester, this is usually the upper radiator hose (top) or lower radiator hose (bottom), and the process is similar for both.

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

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⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap hot; scalding coolant risk.
• ⚠️ Support the vehicle with jack stands if you lift it; never rely on a floor jack.
• ⚠️ Coolant is toxic to people and pets; catch and dispose properly.
• ⚠️ Keep hands/loose clothing away from fans and belts when running the engine to bleed air.
• 🔋 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 2-gallon)
• Pliers (hose clamp pliers)
• Channel-lock pliers
• Pick tool
• Trim clip remover
• 10mm socket
• 3/8" ratchet
• Flathead screwdriver
• Funnel
• Spill-free coolant funnel kit (specialty)
• 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 - Qty: 2-4
• Subaru Super Coolant (blue) premixed - 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 completely (radiator hoses should feel cool to the touch).
• Set the cabin heat to HOT before bleeding later; this helps move coolant through the heater core (the small radiator inside the dash).
• Place a drain pan under the front of the vehicle.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Relieve cooling system pressure (cold engine only)

• Use a shop rag and slowly loosen the radiator cap to the first stop to relieve any leftover pressure.
• Once you’re sure there’s no pressure, remove the cap fully by hand.

Step 2: Raise the front (if needed for the lower hose/undershield)

• Lift the front with a floor jack (rated 3-ton minimum) at the front jacking point.
• Set it down securely on jack stands (rated 3-ton minimum).

Step 3: Remove the lower engine cover (splash shield)

• Use a trim clip remover and flathead screwdriver to remove plastic clips.
• Use a 10mm socket with a 3/8" ratchet to remove any 10mm bolts.
• Set the cover and fasteners aside in a small pile. Keep clips by location.

Step 4: Drain enough coolant to drop the level below the hose

• Position the drain pan (at least 2-gallon) under the radiator drain (petcock) area.
• Open the drain carefully by hand or with a flathead screwdriver (depending on style).
• Drain until the coolant level is below the hose you’re replacing (usually 1-2 quarts is enough).
• Close the drain. No published torque for the plastic drain; close snug by hand only.

Step 5: Remove the old hose clamps

• Use pliers (hose clamp pliers) to squeeze the spring clamp tabs and slide the clamp back onto the hose.
• If your hose has a worm-gear clamp, loosen it with a flathead screwdriver.
• Wipe the area with shop rags to keep coolant off belts and wiring.

Step 6: Remove the old radiator hose

• Twist the hose gently by hand to break it loose from the fitting.
• If it’s stuck, carefully work around the edge using a pick tool to break the seal. (A pick tool is a small hook tool used to separate stuck rubber from metal.)
• Pull the hose off and aim it into the drain pan to catch any remaining coolant.
• Do not pry hard on radiator necks; the plastic can crack.

Step 7: Prep the fittings and install the new hose

• Clean the radiator neck and engine-side fitting using shop rags.
• Slide the clamps onto the new hose first.
• Push the new hose on fully until it bottoms out on the fitting bead/stop.
• Position the clamp behind the raised bead on the fitting, then release/tighten it using pliers (hose clamp pliers) or a flathead screwdriver.
• No published torque for hose clamps; tighten until snug and the hose cannot rotate.

Step 8: Reinstall the lower engine cover (if removed)

• Reinstall the splash shield using the 10mm socket, 3/8" ratchet, and plastic clips with the trim clip remover.
• Lower the vehicle using the floor jack (rated 3-ton minimum).

Step 9: Refill coolant

• Install a spill-free coolant funnel kit (specialty) on the radiator fill neck.
• Slowly add Subaru Super Coolant (blue) premixed using a funnel until the radiator stays full.
• Fill the coolant reservoir to the FULL line.

Step 10: Bleed air from the cooling system

• Start the engine and let it idle with the funnel in place.
• Set HVAC to heat high and fan on low/medium (you should feel heat once coolant circulates).
• Watch for bubbles in the funnel; add coolant as the level drops.
• As the engine warms up, carefully squeeze the upper hose a few times (with nitrile gloves) to help move trapped air.
• When bubbles stop and the heater blows hot steadily, shut the engine off and let it cool.
• Remove the funnel and install the radiator cap by hand. No published torque; tighten fully until it stops.

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✅ After Repair

• With the engine fully cool, recheck the radiator level and the reservoir level; top off with Subaru Super Coolant (blue) premixed as needed.
• Start the engine and inspect both ends of the replaced hose for seepage.
• Take a short drive, then recheck for leaks and recheck the reservoir level the next morning.
• If you ever see overheating, shut down immediately and recheck for trapped air/leaks.

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💰 DIY vs Shop Cost

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

DIY Cost: $40-$180 (parts only)

You Save: $210-$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.