🔧 Impreza - Water Pump Replacement

On your Impreza’s 2.0L FB engine, the water pump is located behind the front timing cover and is driven by the timing chain. Replacing it is a major job because you must remove the timing cover and reseal it to prevent oil leaks and coolant leaks.

Assumption: FB20 timing-chain-driven water pump (typical for this engine family); use OEM torque specs for your exact fasteners.

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

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine only; hot coolant can cause severe burns.
• ⚠️ Support the car with jack stands; never rely on a floor jack.
• ⚠️ Keep coolant off belts/electrical connectors; wipe spills immediately.
• ⚠️ Timing chain components must stay correctly aligned; incorrect timing can cause a no-start or engine damage.
• ⚠️ Battery disconnect is recommended before working around fans and the crank pulley.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Wheel chocks
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Drain pan (at least 10-quart)
• Funnel
• Trim clip removal tool
• Plastic razor scraper
• Shop rags
• Metric socket set 8mm-22mm
• Metric wrench set 8mm-19mm
• 3/8" drive ratchet
• 1/2" drive breaker bar
• Torque wrench 10-80 ft-lbs
• Torque wrench 80-200 ft-lbs
• Extensions (3" and 6")
• Universal joint adapter
• Screwdriver set (Phillips #2, flat blade)
• Pliers (hose clamp)
• Serpentine belt tool or long 14mm wrench
• Crank pulley holding tool (specialty)
• Harmonic balancer puller kit (specialty)
• RTV engine sealant (OEM-equivalent)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Water pump assembly - Qty: 1
• Water pump gasket / O-ring - Qty: 1
• Engine coolant (Subaru-compatible) - Qty: 2-3 gallons
• Front timing cover sealant (OEM-equivalent RTV) - Qty: 1
• Accessory drive belt - Qty: 1
• Thermostat gasket - Qty: 1
• Fresh hose clamps (assorted) - Qty: 1 set

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📋 Before You Begin

• Park on level ground, set the parking brake, and place wheel chocks behind the rear wheels.
• Disconnect the negative battery terminal using a 10mm socket and tuck it aside.
• Raise the front of the car with a floor jack and support it on jack stands at the pinch welds.
• Remove the lower engine splash shield using a trim clip removal tool and 10mm socket.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Drain the coolant

• Place a drain pan (at least 10-quart) under the radiator drain.
• Open the radiator cap slowly (engine cold) and open the drain using the appropriate Phillips #2 screwdriver or by hand (varies by radiator style).
• Open the overflow tank cap and let the system drain fully.
• Keep pets away; coolant is toxic.

Step 2: Remove the air intake ducting for room

• Loosen hose clamps with a flat blade screwdriver.
• Remove the duct/air box snorkel clips with a trim clip removal tool and set ducting aside.

Step 3: Remove the radiator fans

• Unplug the fan electrical connectors by pressing the lock tabs (use a flat blade screwdriver gently if stuck).
• Remove fan shroud bolts using a 10mm socket.
• Lift the fan assemblies straight up and out.

Step 4: Remove the accessory drive belt

• Use a serpentine belt tool or long 14mm wrench on the belt tensioner to relieve tension.
• Slide the belt off one pulley, then remove it fully.
• Take a quick photo of belt routing.

Step 5: Remove the crank pulley (harmonic balancer)

• Install a crank pulley holding tool (specialty) to prevent the crank from turning (this tool locks the pulley so you can loosen/tighten the bolt safely).
• Use a 1/2" drive breaker bar and appropriate socket from your metric socket set 8mm-22mm to remove the crank pulley bolt.
• If the pulley is stuck, use a harmonic balancer puller kit (specialty) to pull it off evenly (a puller uses threaded bolts to press the pulley off without prying).
• Torque to manufacturer spec when reinstalling the crank bolt.

Step 6: Remove components blocking the timing cover

• Disconnect any brackets and harness retainers from the front cover using a 10mm socket and trim clip removal tool.
• Remove front cover fasteners using a metric socket set 8mm-22mm, extensions (3" and 6"), and a universal joint adapter where needed.
• Keep bolts organized by location; lengths vary.

Step 7: Remove the timing cover

• Carefully separate the cover from the engine using a plastic razor scraper and gentle hand pressure.
• Do not gouge the aluminum sealing surfaces.
• Once loose, remove the cover and set it on a clean surface.

Step 8: Set the engine to the correct timing position and mark it

• Rotate the engine only by hand using a socket on the crank (use a 3/8" drive ratchet and appropriate socket) until timing marks align.
• Make extra reference marks with a paint pen (use your shop rags to clean, then mark) on chain/sprockets so you can verify alignment during reassembly.
• Do not rotate cam sprockets independently.

Step 9: Remove the water pump

• Place the drain pan under the pump area; more coolant will spill.
• Remove the pump mounting bolts using a metric socket set 8mm-22mm and 3/8" drive ratchet.
• Pull the water pump straight off and remove the old gasket/O-ring.
• Torque to manufacturer spec when installing the new pump bolts.

Step 10: Clean gasket surfaces and install the new water pump

• Clean mating surfaces with a plastic razor scraper and shop rags.
• Install the new gasket/O-ring on the new pump (lightly wet with fresh coolant if it’s an O-ring).
• Install the pump and hand-start all bolts, then tighten evenly with a torque wrench 10-80 ft-lbs.
• Torque to manufacturer spec.

Step 11: Reseal and reinstall the timing cover

• Remove old sealant from the cover and engine using a plastic razor scraper and shop rags.
• Apply a continuous bead of RTV engine sealant (OEM-equivalent) to the timing cover sealing path.
• Install the cover carefully without smearing the bead, then install bolts finger-tight.
• Tighten bolts in a crisscross pattern using a torque wrench 10-80 ft-lbs.
• Torque to manufacturer spec.

Step 12: Reinstall the crank pulley and belt

• Reinstall the pulley and crank bolt using a crank pulley holding tool (specialty) and torque wrench 80-200 ft-lbs.
• Torque to manufacturer spec.
• Install the accessory belt using a serpentine belt tool or long 14mm wrench to move the tensioner.

Step 13: Reinstall radiator fans, intake ducting, and splash shield

• Install fans and tighten bolts with a 10mm socket.
• Reconnect fan electrical connectors firmly.
• Reinstall intake ducting and tighten clamps with a flat blade screwdriver.
• Reinstall the splash shield using a trim clip removal tool and 10mm socket.

Step 14: Refill and bleed the cooling system

• Close the radiator drain.
• Refill with engine coolant (Subaru-compatible) using a funnel.
• Start the engine and let it idle with the heater set to HOT; watch for air bubbles and top off as needed.
• When the cooling fans cycle and heat is steady, shut the engine off and let it cool completely, then recheck the level.

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✅ After Repair

• Check for coolant leaks around the water pump, timing cover, and hoses with the engine running.
• Check for oil leaks at the timing cover seam after a short test drive.
• Verify the temperature gauge stays normal and cabin heat works.
• Recheck coolant level the next morning (engine cold) and top off if needed.

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💰 DIY vs Shop Cost

Shop Cost: $1,000-$2,000 (parts + labor)

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

You Save: $550-$1,800 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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