🔧 2500 - Spark Plug Replacement

On your 2500’s 6.4L HEMI, there are 16 spark plugs (two per cylinder). Replacing them restores smooth idle, power, and fuel economy, and helps prevent misfires.

Difficulty Level: Intermediate | Estimated Time: 2.0-4.0 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully; plugs in a hot aluminum head can strip threads.
• ⚠️ Disconnect the negative battery cable to prevent accidental shorting while unplugging ignition coils.
• ⚠️ Blow dirt away from each plug well before removing the plug to avoid debris falling into the cylinder.
• ⚠️ Do not use anti-seize on the new plugs unless the plug manufacturer explicitly requires it (most OE-style plated plugs do not).

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Mechanic gloves
• 3/8" drive ratchet
• 3/8" drive torque wrench (in-lb capable)
• 10mm socket
• 5/8" spark plug socket (rubber insert or магнит type)
• 3/8" drive extension set (3", 6", 10")
• 3/8" drive universal joint
• Pick tool
• Feeler gauge set
• Compressed air blow gun
• Dielectric grease
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OE-spec for 6.4L HEMI) - Qty: 16

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool completely.
• Use a 10mm socket to disconnect the negative battery cable and isolate it so it can’t spring back.
• Work one coil/plug at a time.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Pull up evenly on the cover to release the grommets, or remove fasteners if your cover is bolted (use a 10mm socket if needed).
• Set the cover aside.

Step 2: Pick a cylinder and access the ignition coil

• Locate an ignition coil on top of the valve cover (a coil is the small module that makes spark for the plug).
• Use a flashlight to see the coil connector lock.

Step 3: Unplug the coil electrical connector

• Use a pick tool to gently lift the connector lock (do not break it).
• Press the tab and pull the connector straight off.

Step 4: Remove the ignition coil

• Use a 10mm socket and 3/8" drive ratchet to remove the coil retaining bolt.
• Twist the coil slightly, then pull it straight up and out.
• If it feels stuck, twist—don’t pry.

Step 5: Clean the spark plug well

• Use compressed air blow gun to blow out dirt around the plug before loosening it.
• This prevents debris from falling into the cylinder.

Step 6: Remove the old spark plug

• Install the 5/8" spark plug socket with the needed 3/8" drive extension (use a 3/8" drive universal joint if access is tight).
• Loosen and remove the plug slowly. If it feels unusually tight, stop and re-tighten slightly, then loosen again.

Step 7: Check and prep the new spark plug

• Use a feeler gauge set to confirm the gap matches the specification on the plug box/underhood emissions label.
• Do not bend the fine center electrode on iridium/platinum plugs.
• Apply a small dab of dielectric grease inside the coil boot (this helps prevent moisture and makes future removal easier).

Step 8: Install the new spark plug

• Start the plug by hand using the 5/8" spark plug socket and an extension only (no ratchet at first) to avoid cross-threading.
• Once it seats, torque it with a 3/8" drive torque wrench (in-lb capable): Torque to 13 Nm (115 in-lbs).

Step 9: Reinstall the ignition coil

• Push the coil straight down until fully seated on the plug.
• Install the coil bolt using a 10mm socket.
• Tighten with a torque wrench: Torque to 9 Nm (80 in-lbs).
• Reconnect the coil electrical connector until it clicks and re-engage the lock.

Step 10: Repeat for all spark plugs (16 total)

• Repeat Steps 2–9 for each coil/plug.
• Keep coils matched to their original positions if you’re reusing them.

Step 11: Reinstall engine cover and reconnect the battery

• Reinstall the engine cover (press into grommets or tighten bolts with a 10mm socket if equipped).
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• Start the engine and listen for a smooth idle. A steady check-engine light or shaking usually means a coil connector isn’t fully seated.
• Test drive 10–15 minutes and recheck for any warning lights.
• If you get a misfire code, re-check that cylinder’s coil plug-in.

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💰 DIY vs Shop Cost

Shop Cost: ₹18,000-₹40,000 (parts + labor)

DIY Cost: ₹6,000-₹18,000 (parts only)

You Save: ₹12,000-₹22,000 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2.0-4.0 hours.

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🎯 Ready to get started?

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