How to Replace the Upper or Lower Radiator Hose on a 2020 Subaru Outback
Step-by-step DIY guide with required tools/parts, coolant refill & air bleeding tips, and leak checks for 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025
How to Replace the Upper or Lower Radiator Hose on a 2020 Subaru Outback
Step-by-step DIY guide with required tools/parts, coolant refill & air bleeding tips, and leak checks for 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025
đź”§ Outback - Radiator Hose Replacement
On your Outback, the radiator hoses carry coolant between the engine and radiator. Replacing a swollen, cracked, or leaking hose is mostly a remove-and-reinstall job, but the key is staying safe around hot coolant and properly refilling/bleeding air afterward.
Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours
⚠️ Safety & Precautions
- ⚠️ Never open the radiator cap on a hot engine; hot coolant can spray and burn.
- ⚠️ Support the vehicle on jack stands if you lift it; never rely on a jack alone.
- Wear nitrile gloves and safety glasses; coolant is toxic and slippery.
- Keep coolant away from kids/pets; clean spills immediately.
- Battery disconnect is not required for this repair.
đź”§ Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Nitrile gloves
- Drain pan (at least 10-quart)
- Spill-free coolant funnel kit (specialty)
- Pliers for spring hose clamps
- Channel-lock pliers
- Flathead screwdriver
- Hose pick tool (specialty)
- 10mm socket
- 12mm socket
- 3/8" ratchet
- Trim clip removal tool
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Torque wrench (10-80 Nm range)
- Shop rags
- Flashlight
🔩 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: 2-4
- Subaru-approved coolant (blue long-life premix 50/50) - Qty: 2 gallons
đź“‹ Before You Begin
- Park on level ground, set the parking brake, and let the engine cool fully (ideally 2+ hours).
- Set the HVAC to full hot later during bleeding (this opens coolant flow through the heater core).
- If you need more access, raise the front and support with jack stands at the front pinch welds.
- Identify the hose you’re replacing:
- Upper hose: top of radiator to top/front of engine.
- Lower hose: bottom of radiator to lower/front of engine (usually tighter access).
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the lower engine cover (if equipped)
- Use a trim clip removal tool to pop out the plastic clips.
- Use a 10mm socket and 12mm socket with a 3/8" ratchet to remove any bolts holding the cover.
- Set the cover and hardware aside in a small pile so nothing gets lost. Take a quick photo first.
Step 2: Relieve pressure safely
- Confirm the engine is stone-cold by touching the upper radiator hose; it should feel cool.
- Place shop rags around the radiator cap area.
- Slowly loosen the radiator cap by hand to the first stop to vent any leftover pressure, then remove it fully.
Step 3: Drain enough coolant to get below the hose level
- Place a drain pan (at least 10-quart) under the radiator drain.
- Open the radiator drain cock using a flathead screwdriver (turn slowly) and drain 1-2 gallons, or until the coolant level is below the hose you’re replacing.
- Close the drain cock (snug by hand with the screwdriver—do not overtighten).
Step 4: Remove the old hose clamp(s)
- If your Outback has spring clamps, squeeze them with pliers for spring hose clamps and slide the clamp back onto the hose.
- If someone installed a screw-type clamp, loosen it with a flathead screwdriver and slide it back.
- A clamp is the metal ring that squeezes the hose.
Step 5: Break the hose loose and remove it
- Twist the hose by hand to break the seal. Use channel-lock pliers gently if it’s stuck.
- If the hose won’t budge, carefully slide in a hose pick tool (specialty) between the hose and fitting to let air in and loosen it. Don’t gouge the plastic radiator neck.
- Pull the hose off and aim it into the drain pan to catch leftover coolant.
Step 6: Inspect and clean the hose connections
- Use shop rags to wipe the radiator neck and engine fitting clean.
- Use a flashlight to inspect for cracks at the radiator neck and corrosion on the engine fitting.
- If a fitting is damaged, stop here—new hose won’t seal reliably.
Step 7: Install the new hose and position clamps correctly
- Slide the clamp(s) onto the new hose first.
- Push the hose fully onto the radiator and engine fittings until it bottoms out (no gap).
- Position the clamp about 5-8 mm (about 1/4") from the end of the hose, centered over the fitting bead.
- For spring clamps: release using pliers for spring hose clamps so it clamps down evenly.
- For screw-type clamps (if used): tighten with a flathead screwdriver until snug—do not crush the hose.
Step 8: Reinstall the lower engine cover
- Reinstall the cover using the 10mm socket, 12mm socket, and 3/8" ratchet.
- If you have a torque wrench available for small bolts, use it: Torque to 7.5 Nm (66 in-lbs) for small under-cover bolts.
- Reinstall the clips using the trim clip removal tool to line them up, then press in.
Step 9: Refill coolant and bleed air
- Install a spill-free coolant funnel kit (specialty) onto the radiator fill neck.
- Slowly add Subaru-approved coolant (blue long-life premix 50/50) until the radiator stays full.
- Fill the overflow reservoir to the “FULL” line.
- Start the engine and set the heat to max hot and fan on low.
- Let it idle and watch the funnel level; add coolant as bubbles purge out.
- When the engine warms up, the radiator fans may cycle—keep hands clear.
- Once bubbles slow down and you have steady heat from the vents, shut the engine off and let it cool.
- Top off the radiator and overflow reservoir again, then install the radiator cap fully by hand.
Step 10: Check for leaks
- With the engine running, use a flashlight to inspect both ends of the new hose.
- Look for seepage around the clamp area and drips under the car.
- If you see a leak, shut off the engine, let it cool, then reposition/tighten the clamp.
âś… After Repair
- Test drive 10-15 minutes, then park and recheck for leaks with a flashlight.
- After the engine cools completely, recheck the overflow reservoir and top off to the “FULL” line if needed.
- Watch the temperature gauge over the next few drives; overheating means air may still be trapped.
- Dispose of old coolant properly (do not dump it).
đź’° DIY vs Shop Cost
Shop Cost: $250-$550 (parts + labor)
DIY Cost: $45-$140 (parts only)
You Save: $110-$505 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.
🎯 Ready to get started?
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