How to Replace the Water Pump on a 2020 Subaru Forester (2.5L Boxer)
Step-by-step DIY instructions with tools, parts list, torque specs, coolant refill/bleed tips, and leak checks for 2019, 2020, 2021, 2022
How to Replace the Water Pump on a 2020 Subaru Forester (2.5L Boxer)
Step-by-step DIY instructions with tools, parts list, torque specs, coolant refill/bleed tips, and leak checks for 2019, 2020, 2021, 2022
🔧 Forester - Water Pump Replacement
On your Forester, the water pump circulates coolant through the engine and radiator. Replacing it involves draining coolant, removing the drive belt and front-access components, then swapping the pump and gasket and refilling/bleeding the cooling system.
Difficulty Level: Advanced | Estimated Time: 3-5 hours
⚠️ Safety & Precautions
- 🛑 Work only on a fully cool engine; hot coolant can cause severe burns.
- 🛑 Support the vehicle with jack stands; never rely on a jack alone.
- 🛑 Keep coolant off paint and away from pets; it’s toxic.
- 🛑 Disconnect the negative battery terminal if you’ll unplug radiator fans.
🔧 Required Tools
You'll need the following tools for this repair:
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Wheel chocks
- Safety glasses
- Nitrile gloves
- Drain pan (at least 10-quart)
- Funnel
- Trim clip removal tool
- Flathead screwdriver
- Pliers (hose clamp)
- Ratchet (3/8")
- Socket set (8mm, 10mm, 12mm, 14mm)
- Extension set (3" and 6")
- Torque wrench (5-60 Nm range)
- Serpentine belt tool (specialty)
- Gasket scraper (plastic)
- Brake cleaner spray
- Shop towels
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Water pump - Qty: 1
- Water pump gasket / O-ring (as equipped) - Qty: 1
- Subaru-approved coolant (blue, premixed 50/50) - Qty: 2 gallons
- Accessory drive belt - Qty: 1
- Thermostat - Qty: 1 Optional but strongly recommended
- Thermostat gasket - Qty: 1
📋 Before You Begin
- Park on level ground, set the parking brake, and chock the rear wheels.
- Let the engine cool completely (radiator hoses should feel cool).
- If you’ll remove/unplug radiator fans, disconnect the battery using a 10mm socket (negative terminal first).
- Raise the front and support it securely on jack stands.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the under cover (splash shield)
- Use a trim clip removal tool and 10mm socket to remove the clips/bolts holding the under cover.
- Set the hardware aside in a tray so nothing gets lost.
Step 2: Drain the coolant
- Place a drain pan under the radiator.
- Slowly open the radiator cap to release any leftover pressure.
- Open the radiator drain and let coolant drain fully into the pan.
- Use pliers (hose clamp) to remove the lower radiator hose if you need faster draining.
Step 3: Create working room at the front of the engine
- Remove the air intake ducting as needed using a flathead screwdriver and 10mm socket.
- If access is tight, remove the radiator fan assemblies using a 10mm socket and unplug the connectors (press the lock tab before pulling). Fans give you crucial clearance
Step 4: Remove the accessory drive belt
- Use a serpentine belt tool (specialty) to rotate the belt tensioner and relieve belt tension.
- Slip the belt off the pulleys and remove it from the engine bay.
- If you’re reusing the belt (not recommended), note the rotation direction.
Step 5: Remove the water pump pulley
- Hold the pulley from turning by keeping light tension on the old belt or gripping carefully by hand.
- Use a 10mm socket to remove the pulley bolts, then remove the pulley.
- Torque to 10 Nm (7 ft-lbs) when reinstalling.
Step 6: Remove the water pump
- Place the drain pan under the pump area; more coolant will spill.
- Remove any hoses attached to the pump using pliers (hose clamp).
- Use a 10mm socket and 12mm socket (as equipped) to remove the water pump mounting bolts.
- Remove the pump. If it’s stuck, gently wiggle it—do not pry hard against aluminum surfaces.
Step 7: Clean the sealing surface
- Use a gasket scraper (plastic) to remove old gasket material from the engine surface.
- Spray brake cleaner spray on a shop towel and wipe until clean and dry.
- Clean metal-to-gasket contact prevents leaks
Step 8: Install the new water pump and gasket
- Install the new gasket/O-ring onto the new pump (make sure it sits flat and isn’t twisted).
- Position the pump and hand-start all bolts to avoid cross-threading.
- Tighten bolts evenly in a crisscross pattern using a 10mm socket/12mm socket.
- Torque to 10 Nm (7 ft-lbs) for water pump bolts.
Step 9: Reinstall pulley, belt, and removed components
- Install the pulley and bolts using a 10mm socket, then torque to 10 Nm (7 ft-lbs).
- Route the belt correctly and use the serpentine belt tool (specialty) to move the tensioner and slip the belt on.
- Reinstall radiator fans (if removed) using a 10mm socket and reconnect the electrical connectors.
- Reinstall the air ducting using a flathead screwdriver and 10mm socket.
Step 10: Refill and bleed the cooling system
- Close the radiator drain.
- Use a funnel to fill the radiator and overflow tank with Subaru-approved coolant (blue, premixed 50/50).
- Start the engine and set the heater to MAX heat (fan on low) to help purge air.
- Let it idle and watch the temperature gauge; top off coolant as the level drops.
- When the radiator fans cycle on/off and heat blows consistently hot, shut the engine off and let it cool, then recheck and top off.
✅ After Repair
- Check for leaks around the water pump and hose connections with the engine running.
- Verify the belt tracks smoothly and isn’t squealing.
- After the first drive and full cool-down, recheck coolant level in the overflow tank and top off if needed.
- If the temperature rises abnormally, shut down and re-bleed—air pockets can cause overheating.
💰 DIY vs Shop Cost
Shop Cost: ₹18,000-₹35,000 (parts + labor)
DIY Cost: ₹6,000-₹18,000 (parts only)
You Save: ₹12,000-₹17,000 by doing it yourself!
Shop labor rates vary but typically run ₹1,000-₹2,500/hour. This repair takes a shop approximately 3-5 hours.
🎯 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.


















