🔧 Forester - Radiator Hose Replacement

On your Forester, the radiator hoses (upper and lower) carry coolant between the engine and radiator. Replacing a leaking, swollen, or cracked hose prevents overheating and coolant loss.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.5 hours

---

⚠️ Safety & Precautions

• ⚠️ Never open the radiator cap on a hot engine; hot coolant can spray out.
• ⚠️ Coolant is toxic—keep away from kids/pets and clean spills immediately.
• If you need to reach from underneath, support the Forester with jack stands on solid, level ground.
• Battery disconnect is not required for this job.

---

🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Drain pan (at least 10-quart)
• Funnel
• Slip-joint pliers
• Hose clamp pliers (specialty)
• Flathead screwdriver
• Pick tool (small) (specialty)
• Razor blade or hose cutter
• Trim clip removal tool
• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension (6")
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks

---

🔩 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 - Replace in pairs - Qty: 2-4
• Subaru-compatible coolant (blue, pre-mixed 50/50) - Qty: 2-3 gallons

---

📋 Before You Begin

• Park on level ground, set the parking brake, and let the engine cool completely.
• Set the climate control to full heat (HI). This helps coolant circulate through the heater core during bleeding.
• Place a drain pan under the front of the vehicle before loosening any hose or drain.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Confirm which hose you’re replacing

• The upper radiator hose runs from the top of the radiator to the top/front of the engine.
• The lower radiator hose runs from the bottom of the radiator to the lower part of the engine.
• Do one hose at a time.

Step 2: Remove the radiator cap (only when cold)

• Use your hand to slowly twist the radiator cap to the first stop and let any pressure release.
• Remove the cap fully once there is no hiss or pressure.

Step 3: Raise the front (if you need access)

• Use wheel chocks behind the rear wheels.
• Use a floor jack (rated 3-ton minimum) to lift the front at the proper front jacking point.
• Set the Forester onto jack stands (rated 3-ton minimum).

Step 4: Remove the lower splash shield (if equipped/needed)

• Use a trim clip removal tool to remove plastic clips.
• Use a 10mm socket, 3/8" ratchet, and extension to remove any 10mm bolts.
• Set the panel and fasteners aside in order.

Step 5: Drain enough coolant to get the hose off cleanly

• Place your drain pan under the radiator drain area.
• If you can access the radiator drain, open it carefully by hand; otherwise, you can drain by loosening the lower hose slowly.
• Use slip-joint pliers to slowly crack the hose loose and let coolant flow into the pan.
• Drain until the radiator level is below the hose.

Step 6: Remove the old hose clamps

• If you have spring-style clamps, use hose clamp pliers (specialty) to squeeze and slide the clamp back on the hose.
• If you have screw-type clamps, loosen with a flathead screwdriver.
• Slide the clamp far enough back so it’s not gripping the fitting.

Step 7: Remove the old radiator hose

• Twist the hose by hand to break it free.
• If it’s stuck, use a pick tool (small) (specialty) to gently lift the hose edge off the fitting to let air in.
• If the hose is hardened and won’t release, carefully slit it with a razor blade or hose cutter (avoid cutting the plastic radiator neck).

Step 8: Clean and inspect the connections

• Wipe the radiator neck and engine fitting clean with a shop towel (use nitrile gloves).
• Inspect the radiator neck for cracks and the fitting for heavy corrosion or pitting.

Step 9: Install the new hose and clamps

• Match the new hose shape to the old hose before installing.
• Slide the clamp onto the hose first.
• Push the hose fully onto the fitting until it bottoms out (no gap).
• Position the clamp behind the raised “bead” on the fitting, then release/tighten it using hose clamp pliers (specialty) or a flathead screwdriver.
• Clamp sits straight, not crooked.

Step 10: Reinstall the splash shield

• Reinstall the panel using a 10mm socket, 3/8" ratchet, and trim clip removal tool for the clips.

Step 11: Refill coolant

• Use a funnel to refill the radiator with Subaru-compatible coolant (blue, pre-mixed 50/50).
• Fill the overflow reservoir to the “FULL” mark.

Step 12: Bleed air and check for leaks

• Start the engine and let it idle with the radiator cap off.
• Turn the heat to HI and fan to low/medium.
• Watch for bubbles and add coolant as the level drops.
• Once the upper hose feels hot (thermostat opened) and bubbles reduce, install the radiator cap by hand.
• Check both hose ends for seepage.

---

✅ After Repair

• Test drive 10-15 minutes, then park and let the engine cool fully.
• Recheck the overflow reservoir level and top off to “FULL” if needed.
• Inspect the new hose connections again for any wetness.
• Over the next 1-2 days, recheck coolant level each morning (engine cold).

---

💰 DIY vs Shop Cost

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

DIY Cost: $60-$180 (parts only)

You Save: $190-$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.

---

🎯 Ready to get started?

Before I tailor this exactly to your Forester, answer these two quick questions: (1) Are you replacing the upper hose, the lower hose, or both? (2) Do you have spring clamps or screw-type clamps on the hose now?

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.