🔧 Spark Plugs - Replacement

On your Outback, the spark plugs sit low in the boxer engine heads, so the job is mostly about gaining side access and working carefully around the ignition coils. Replacing all four plugs restores smooth idle, better fuel economy, and easier cold starts when the originals are worn.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• Work on a cool engine. The plugs and cylinder heads get very hot.
• Disable the ignition before unplugging coils. A battery disconnect is recommended for safety.
• Use jack stands if you raise the vehicle. Never work under a car supported only by a jack.
• Keep dirt out of the plug wells. Debris can damage the cylinders when the plugs are removed.
• Do not over-tighten the plugs. The aluminum heads can be damaged easily.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 14mm spark plug socket
• 3/8-inch ratchet
• 3-inch extension
• 6-inch extension
• Wobble extension
• Torque wrench
• Flat trim tool
• Needle-nose pliers
• Floor jack
• Jack stands
• Wheel chocks
• Safety glasses
• Mechanic gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plug set - Qty: 4

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool fully.
• Disconnect the negative battery cable using a 10mm socket.
• If you raise the car for better access, support it securely with jack stands.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Prepare access on both sides

• Open the hood and remove any loose engine cover if equipped.
• If needed for easier side access, raise the front of the vehicle with a floor jack and support it with jack stands.
• Turn the steering wheel for better wheel-well access on the side you are working on.

Step 2: Remove the ignition coil on one cylinder

• Use a 10mm socket to remove the ignition coil hold-down bolt.
• Pull the coil straight out. Use a gentle wiggle if it is stuck.
• Unplug the electrical connector if it blocks removal.
• Keep dirt out of the plug well.

Step 3: Remove the old spark plug

• Use a 14mm spark plug socket with a 3-inch extension or wobble extension to reach the plug.
• Break the plug loose slowly, then spin it out by hand.
• Check the removed plug for heavy wear, oil, or damage.

Step 4: Install the new spark plug

• Start the new plug by hand using the 14mm spark plug socket and extension.
• Thread it in carefully so it does not cross-thread.
• Tighten with a torque wrench to 25 Nm (18.4 ft-lbs).

Step 5: Reinstall the ignition coil

• Push the coil fully onto the new plug.
• Reinstall the coil bolt with a 10mm socket.
• Torque to 7.5 Nm (5.5 ft-lbs).
• Reconnect the electrical connector.

Step 6: Repeat for the remaining cylinders

• Repeat Steps 2 through 5 for all four plugs.
• Work one cylinder at a time so parts stay organized.

Step 7: Reassemble and restore power

• Reinstall any removed covers or intake parts using the 10mm socket.
• Reconnect the negative battery cable with the 10mm socket.

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✅ After Repair

• Start the engine and let it idle.
• Listen for a smooth idle and check for a warning light.
• If the engine runs rough, recheck coil connections and plug seating.
• Test drive gently for a few minutes.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $45-$120 (parts only)

You Save: $175-$300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

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🎯 Ready to get started?

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