🔧 Impreza - Timing Chain Service (No Timing Belt)

Your Impreza does not use a timing belt—it uses a timing chain. A chain normally has no scheduled replacement interval; it’s serviced only if there’s a problem (rattle at startup, cam/crank correlation codes, oil leaks from the front cover, or confirmed chain stretch).

Difficulty Level: Advanced | Estimated Time: 10-14 hours

Assumption: You meant timing system service on the FB20 timing chain.

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine; hot coolant/oil can burn.
• ⚠️ Support the engine safely before removing any engine mount.
• ⚠️ Keep hands clear when rotating the crankshaft by hand.
• ⚠️ Disconnect the negative battery cable before starting.
• ⚠️ Keep dirt out of the open engine; cleanliness is critical for sealing.

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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)
• Fender cover
• Metric socket set 8mm-19mm
• Metric wrench set 8mm-19mm
• 1/4" ratchet
• 3/8" ratchet
• 1/2" breaker bar
• Torque wrench 10-80 Nm
• Torque wrench 60-250 Nm
• Extensions (3", 6", 12")
• Universal joint adapter 3/8"
• Trim clip remover
• Flat screwdriver
• Phillips screwdriver
• Pry bar 12"
• Harmonic balancer puller kit (specialty)
• Crank pulley holding tool (specialty)
• Engine support bar (specialty)
• Gasket scraper plastic
• Razor blade scraper
• Brake cleaner spray
• Shop rags
• Paint marker
• OBD2 scan tool
• Funnel

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Timing chain - Qty: 1
• Timing chain guides set - Qty: 1
• Timing chain tensioner - Qty: 1
• Front timing cover reseal kit - Qty: 1
• Front crankshaft seal - Qty: 1
• Engine oil (0W-20 full synthetic) - Qty: 6 quarts
• Oil filter - Qty: 1
• Engine coolant (Subaru-compatible long-life) - Qty: 2 gallons
• Accessory drive belt - Qty: 1
• RTV engine sealant (Subaru-compatible) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Disconnect the negative battery cable using a 10mm socket.
• Raise the front and support with jack stands (rated 3-ton minimum).
• Plan to do an oil change and coolant refill after resealing the front cover.
• Take photos as you disassemble.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove lower covers and drain fluids

• Remove the lower engine splash shield using a trim clip remover and 10mm socket.
• Place a drain pan (at least 10-quart) under the radiator drain and drain coolant using pliers or a flat screwdriver (as equipped).
• Drain engine oil using a 14mm socket, then remove the oil filter with an oil filter wrench 65-75mm.

Step 2: Remove the radiator fans (creates working room)

• Unplug the fan connectors by hand.
• Remove fan shroud bolts using a 10mm socket, then lift the fans out carefully.

Step 3: Remove the accessory drive belt

• Rotate the belt tensioner with a 14mm socket and 3/8" ratchet to release belt tension.
• Slip the belt off and remove it from the engine bay.

Step 4: Support the engine and remove the RH engine mount (needed for cover access)

• Install an engine support bar (specialty) across the fenders and lightly tension it. (An engine support bar holds the engine from above.)
• Remove the RH engine mount fasteners using a 14mm socket and 17mm socket.
• Torque to Subaru OEM spec during reassembly.

Step 5: Remove the crank pulley (harmonic balancer)

• Install the crank pulley holding tool (specialty) to prevent the crank from turning. (This tool locks the pulley so you can loosen the bolt safely.)
• Remove the crank pulley bolt using a 22mm socket and 1/2" breaker bar.
• If the pulley is stuck, use a harmonic balancer puller kit (specialty) to pull it off straight.
• Torque to Subaru OEM spec for the crank bolt during reassembly.

Step 6: Set cylinder #1 to Top Dead Center (TDC) on compression

• Rotate the crankshaft clockwise using a 22mm socket and 1/2" ratchet.
• Align the timing marks per Subaru procedure, then add your own reference marks using a paint marker.
• Only rotate clockwise to avoid slack errors.

Step 7: Remove the front timing cover

• Remove all front cover bolts using a 10mm socket and 12mm socket (bolt lengths vary).
• Gently separate the cover using a pry bar 12" at designated pry points only.
• Do not gouge sealing surfaces; clean old RTV with a gasket scraper plastic and razor blade scraper.
• Clean surfaces with brake cleaner spray and shop rags until oil-free.

Step 8: Release tension and remove the timing chain

• Remove the timing chain tensioner bolts using a 10mm socket and carefully remove the tensioner.
• Remove chain guides using a 10mm socket.
• Remove the chain while keeping cam/crank sprockets from moving; mark relationships with a paint marker.
• Torque to Subaru OEM spec for tensioner and guide bolts during reassembly.

Step 9: Install new chain, guides, and tensioner

• Install the new chain aligned to the factory timing marks (use your paint marker references too).
• Install new guides using a 10mm socket.
• Install the new tensioner using a 10mm socket, then release/activate it per the included instructions.
• Hand-rotate the engine two full turns clockwise using a 22mm socket and re-check all timing marks.
• If marks don’t line up, stop and re-time.

Step 10: Reseal and reinstall the front timing cover

• Apply a continuous bead of RTV engine sealant (Subaru-compatible) to the cover per Subaru pattern (especially at joints).
• Install the cover and hand-start all bolts using a 10mm socket.
• Tighten in a crisscross pattern using a torque wrench 10-80 Nm.
• Torque to Subaru OEM spec for cover bolts.

Step 11: Install new front crank seal (recommended)

• Remove the old seal carefully with a seal puller (specialty) (a seal puller hooks the seal without damaging metal).
• Lightly oil the new seal and press it in evenly using a seal driver kit (specialty).

Step 12: Reinstall crank pulley, mount, belt, and fans

• Install the crank pulley and crank bolt using a 22mm socket and crank pulley holding tool (specialty).
• Torque to Subaru OEM spec for the crank bolt.
• Reinstall the RH engine mount using a 14mm socket and 17mm socket.
• Torque to Subaru OEM spec for mount fasteners.
• Install the new accessory belt using a 14mm socket on the tensioner.
• Reinstall radiator fans using a 10mm socket and reconnect electrical plugs by hand.

Step 13: Refill fluids and recheck everything

• Install a new oil filter by hand, then refill oil using a funnel with 0W-20 full synthetic.
• Close the radiator drain and refill coolant using a funnel.
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle; watch for oil/coolant leaks around the front cover.
• Use an OBD2 scan tool to check/clear any stored codes.
• Bring the engine to operating temperature and top off coolant as needed.
• Road test gently, then re-check oil level and coolant level after it cools.

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💰 DIY vs Shop Cost

Shop Cost: $1,800-$3,500 (parts + labor)

DIY Cost: $350-$850 (parts only)

You Save: $1,450-$2,650 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 10-14 hours.

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🎯 Ready to get started?

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