🔧 Renegade - Spark Plug Replacement

On your Renegade’s 2.4L engine, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starting, fuel economy, and prevents misfires as the plugs wear.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and thread damage in the cylinder head.
• ⚠️ Keep dirt out of the spark plug holes; debris can damage the engine.
• ⚠️ Do not over-tighten spark plugs; stripped threads are expensive to repair.
• ⚠️ Battery disconnect is not required, but disconnecting the negative terminal reduces accidental shorting.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension set (3" and 6")
• 5/8" spark plug socket
• Torque wrench (3/8" drive, 10-40 Nm range)
• Trim clip/panel tool
• Compressed air nozzle
• Feeler gauge set (0.040"-0.050")
• Small flathead screwdriver

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (2.4L-spec) - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine cool completely (at least 1 hour after driving).
• If you choose to disconnect the battery: use a 10mm socket to remove the negative terminal and tuck it aside so it can’t spring back.
• Take a quick photo of coil connectors first.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Gently lift the cover upward to release it from its rubber grommets.
• If any clips/pins are present, use a trim clip/panel tool to pop them loose.

Step 2: Unplug the ignition coil electrical connectors

• Each cylinder has an ignition coil (a “coil-on-plug” unit that sits directly on the spark plug).
• Use a small flathead screwdriver to help lift the connector lock tab (only if needed), then pull the connector straight off.
• Don’t pull on the wires—pull on the connector body.

Step 3: Remove the ignition coils

• Use a 10mm socket and 3/8" drive ratchet to remove each coil retaining bolt.
• Twist the coil slightly, then pull it straight up and out.
• Set coils aside in order (so they go back to the same cylinder).
• When reinstalling later: Torque to 9 Nm (80 in-lbs)

Step 4: Clean the spark plug wells

• Blow out each spark plug hole before removal using a compressed air nozzle.
• This prevents grit from falling into the cylinder.

Step 5: Remove the old spark plugs

• Install a 5/8" spark plug socket with a 3/8" drive extension (6") and 3/8" drive ratchet.
• Turn counterclockwise to loosen, then remove the plug carefully.
• If a plug feels extremely tight, stop and work it back-and-forth gently to avoid thread damage.

Step 6: Check and prep the new spark plugs

• Check the gap with a feeler gauge set (0.040"-0.050").
• Assumption: Most 2.4L applications run about 0.043" (1.1 mm); many plugs come pre-gapped—adjust only if the plug manufacturer allows it.
• Apply a tiny amount of dielectric grease inside each coil boot (dielectric grease helps prevent moisture and eases future removal).
• Do not use anti-seize unless the plug maker requires it.

Step 7: Install the new spark plugs (start by hand)

• Place a new plug into the 5/8" spark plug socket and carefully lower it into the hole.
• Thread it in by hand using the extension only (no ratchet at first). This helps prevent cross-threading (starting the threads crooked).
• Once finger-tight, use a torque wrench (3/8" drive, 10-40 Nm range) to tighten each plug: Torque to 20 Nm (15 ft-lbs)

Step 8: Reinstall the ignition coils

• Push each coil straight down until fully seated on the plug.
• Install the coil bolt using a 10mm socket, then tighten with a torque wrench: Torque to 9 Nm (80 in-lbs)

Step 9: Reconnect coil connectors and reinstall the engine cover

• Push each electrical connector on until it clicks/locks.
• Reinstall the engine cover by aligning the grommets and pressing down firmly.
• If you disconnected the battery, reconnect the negative cable using a 10mm socket and tighten snugly.

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✅ After Repair

• Start the engine and let it idle for 30-60 seconds. It should run smooth with no shaking.
• Listen for any ticking/air leaks around the top of the engine (a connector not fully seated can cause a misfire).
• If the check-engine light comes on or flashes, shut it off and re-check coil connectors and coil seating.
• Take a short test drive, then re-check for any warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $40-$120 (parts only)

You Save: $130-$410 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-2.0 hours.

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🎯 Ready to get started?

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