🔧 WRX - Water Pump Replacement

On your WRX, the water pump sits behind the front timing cover, so replacement is more involved than many cars. You’ll drain coolant, remove the front cover, swap the pump, then reseal the cover and refill/bleed the cooling system.

Difficulty Level: Advanced | Estimated Time: 6-10 hours

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⚠️ Safety & Precautions

• 🛑 Never open the cooling system hot; let the engine cool fully.
• 🧯 Coolant is toxic; keep it off skin/pets and store it sealed.
• 🧱 Support the car with jack stands; never rely on a floor jack.
• 🔋 Disconnect the negative battery terminal to prevent accidental cranking.
• ⚙️ Do not rotate the crankshaft with the timing chain loose; you can cause engine damage.
• 🧴 Timing cover reseal requires RTV sealant; surfaces must be perfectly clean and dry.

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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 10-quart)
• Funnel
• 10mm socket
• 12mm socket
• 14mm socket
• 3/8" ratchet
• 1/2" breaker bar
• Torque wrench (10-200 Nm range)
• Serpentine belt tool or 14mm wrench
• Crank pulley holding tool (specialty)
• Harmonic balancer puller kit (specialty)
• Trim clip remover
• Flat-blade screwdriver
• Plastic scraper
• Brake cleaner spray
• Shop rags
• Paint marker

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Water pump - Qty: 1
• Water pump gasket / O-ring (pump seal) - Qty: 1
• Timing cover RTV sealant (OEM-equivalent) - Qty: 1
• Subaru-approved coolant (pre-mixed) - Qty: 2-3 gallons
• Serpentine belt - Qty: 1
• Thermostat and gasket (recommended while open) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Let the engine cool completely (ideally overnight).
• Disconnect the negative battery terminal using a 10mm socket.
• Raise the front and support with jack stands at the pinch welds or front support points.
• Have brake cleaner and rags ready; resealing the timing cover depends on clean surfaces.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the undertray and drain the coolant

• Place a drain pan (at least 10-quart) under the radiator area.
• Remove the lower engine undertray using a trim clip remover and 10mm socket.
• Open the radiator drain and/or lower drain point carefully with a flat-blade screwdriver (if equipped), and remove the coolant reservoir cap to help flow.
• Tip: Save pets from coolant—clean spills immediately.

Step 2: Remove intake ducting and radiator fan assemblies

• Remove the intake snorkel/ducting with a 10mm socket and flat-blade screwdriver.
• Unplug the radiator fan connectors by hand and release harness clips using a trim clip remover.
• Unbolt the fan shrouds using a 10mm socket, then lift both fan assemblies out.

Step 3: Remove the serpentine belt

• Rotate the belt tensioner using a serpentine belt tool or 14mm wrench and slide the belt off.
• Inspect the belt; if it’s cracked/glazed, replace it now.

Step 4: Remove the crank pulley

• Use a crank pulley holding tool (specialty) to keep the pulley from turning.
• Remove the crank bolt using a 1/2" breaker bar and 14mm socket.
• Remove the crank pulley. If it’s stuck, use a harmonic balancer puller kit (specialty) per the puller instructions.
• During reassembly: Torque to 177 Nm (130 ft-lbs).

Step 5: Access the front timing cover

• Remove any front engine covers/brackets blocking the timing cover using a 10mm socket and 12mm socket.
• Unbolt the front timing cover bolts using a 10mm socket and 12mm socket as applicable.
• Carefully break the RTV seal and remove the cover using a plastic scraper (do not gouge aluminum surfaces).
• During reassembly (typical small cover bolts): Torque to 6.4 Nm (57 in-lbs).

Step 6: Set the engine to the correct position and secure timing

• Use a paint marker to mark the timing chain relationship to sprockets before loosening anything.
• Turn the engine by hand only (crank bolt temporarily installed finger-tight) using a 1/2" breaker bar until timing marks align.
• Tip: Photos help you recheck alignment later.

Step 7: Release chain tension and remove the water pump

• Remove the timing chain tensioner fasteners using a 10mm socket / 12mm socket as applicable.
• Remove the water pump fasteners using a 10mm socket.
• Pull the water pump straight off and remove the old gasket/O-ring.
• During reassembly (water pump bolts): Torque to 9.0 Nm (80 in-lbs).

Step 8: Clean sealing surfaces and install the new water pump

• Clean the mating surfaces with a plastic scraper, then wipe with brake cleaner spray on shop rags until oil-free.
• Install the new gasket/O-ring onto the new pump.
• Install the pump and hand-start all bolts, then tighten evenly with a torque wrench.
• Torque to 9.0 Nm (80 in-lbs).

Step 9: Reinstall timing components and reseal the timing cover

• Reinstall the chain tensioner and verify your paint marks still line up.
• Clean the timing cover and engine sealing surfaces again using brake cleaner spray and shop rags.
• Apply a continuous bead of timing cover RTV sealant per the sealant instructions (bead size and “skin time” matter).
• Install the timing cover and snug bolts evenly using a 10mm socket / 12mm socket, then final-torque with a torque wrench.
• Torque to 6.4 Nm (57 in-lbs) unless a bolt location requires different spec.
• Tip: Uneven tightening can cause leaks.

Step 10: Reinstall crank pulley, belt, fans, and undertray

• Reinstall the crank pulley and crank bolt using a crank pulley holding tool (specialty).
• Torque to 177 Nm (130 ft-lbs).
• Install the serpentine belt using a serpentine belt tool or 14mm wrench and verify it’s seated on every pulley.
• Reinstall both radiator fans using a 10mm socket and reconnect electrical connectors by hand.
• Reinstall the undertray with a trim clip remover and 10mm socket.

Step 11: Refill and bleed the cooling system

• Reconnect the negative battery terminal using a 10mm socket.
• Refill with Subaru-approved coolant (pre-mixed) using a funnel.
• Start the engine and let it warm up while watching coolant level; top off as air purges.
• Turn the heater to HOT to help bleed air from the heater core.
• Check for leaks at the pump and timing cover.

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✅ After Repair

• Let the engine reach operating temperature and confirm the radiator fans cycle on/off.
• Shut down, let it cool fully, then recheck coolant level and top off the reservoir.
• Inspect for seepage around the timing cover seam and water pump area over the next 2-3 drives.
• If you see coolant smell/steam, stop and recheck immediately.

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💰 DIY vs Shop Cost

Shop Cost: $900-$1,600 (parts + labor)

DIY Cost: $180-$450 (parts only)

You Save: $720-$1,150 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 6-10 hours.

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🎯 Ready to get started?

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