🔧 Spark Plugs - Replacement

Your Prius V uses four spark plugs in the engine. Replacing them restores smooth starting, better idle quality, and reliable fuel economy if the old plugs are worn. This is a straightforward job, but the hybrid system and tight access mean you should work carefully.

Difficulty Level: Intermediate | Estimated Time: 1.5-2.5 hours

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⚠️ Safety & Precautions

• Make sure the vehicle is fully OFF and not in READY mode before starting.
• Keep the key/fob at least 20 feet away from the vehicle so it cannot wake up.
• Disconnect the negative 12V battery cable before removing ignition coils. The 12V battery is in the rear cargo area on this vehicle.
• Let the engine cool completely before touching the plugs or coils.
• Do not drop anything into the spark plug wells.
• Use only hand tools to start the plugs. Cross-threading the aluminum cylinder head can cause major damage.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8-inch ratchet
• 6-inch extension
• 14mm spark plug socket
• Torque wrench
• Flat trim tool
• Needle-nose pliers
• Battery terminal wrench
• Compressed air
• Dielectric grease
• Anti-seize compound
• Safety glasses
• Gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs, OEM-spec iridium - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Turn the ignition OFF and remove the key/fob from the vehicle area.
• Open the hood and let the engine cool fully.
• Disconnect the negative 12V battery terminal in the rear cargo area using a battery terminal wrench.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Use both hands to lift the plastic engine cover straight up and off.
• Set it aside in a safe place.

Step 2: Disconnect the ignition coil connectors

• Use a flat trim tool to release each coil connector lock if needed.
• Press the tab and pull the connector straight off each ignition coil.
• Do not pull on the wires.

Step 3: Remove the ignition coils

• Use a 10mm socket, 3/8-inch ratchet, and 6-inch extension to remove the coil hold-down bolts.
• Lift each ignition coil straight out of the spark plug tube.
• If a coil is stuck, twist it gently by hand first.

Step 4: Clean around the spark plug wells

• Use compressed air to blow dirt away from the plug wells.
• This keeps debris from falling into the cylinders.

Step 5: Remove the old spark plugs

• Use a 14mm spark plug socket, 3/8-inch ratchet, and 6-inch extension to loosen and remove each spark plug.
• Turn counterclockwise slowly at first.
• If a plug feels tight, work it back and forth gently.

Step 6: Install the new spark plugs

• Check that the new plugs match the old ones in reach and tip style.
• Start each plug by hand using the 14mm spark plug socket and extension only.
• Thread each plug in until it seats lightly.
• Use a torque wrench to tighten each plug to 18 Nm (13 ft-lbs).
• Hand-start every plug first.

Step 7: Reinstall the ignition coils

• Apply a small amount of dielectric grease inside each coil boot.
• Push each coil straight down onto its spark plug.
• Reinstall the coil bolts with the 10mm socket.
• Torque the coil bolts to 8 Nm (71 in-lbs).

Step 8: Reconnect the coil connectors and battery

• Push each electrical connector on until it clicks.
• Reconnect the negative 12V battery cable in the rear cargo area.

Step 9: Reinstall the engine cover

• Set the cover back in place and press down firmly until it locks.

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✅ After Repair

• Start the vehicle and listen for smooth idle.
• Check the instrument panel for warning lights.
• If the engine runs rough, recheck coil connectors and plug torque.
• Take a short test drive and confirm normal acceleration.

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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 1.0-1.5 hours.

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🎯 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.