Easy⏱ 30 min - 1 h6 steps·Original on iFixit ↗

2013-2018 Nissan Altima Spark Plug Replacement

Every day you use your vehicle, the engine goes through thousands of combustion cycles to keep it running. A key part of this process is the spark plug, which ignites the air-fuel mixture inside the engine. Over time, spark plugs wear out due to heat and carbon buildup, which can lead to rough idling, reduced fuel efficiency, and misfires.

Replacing your spark plugs is an important part of routine maintenance that helps keep your engine running smoothly and efficiently.

Before beginning, ensure the engine is completely cool to avoid burns. It is also recommended to disconnect the battery to prevent electrical issues while working.

This guide demonstrates how to replace the spark plugs on a 2013–2018 Nissan Altima 2.5L 4-cylinder engine.

Tools (5)

10mm Socket (3/8in Drive) buy ↗
3/8" Ratchet buy ↗
3/8" 6" Ratchet Extension buy ↗
9/16th Spark Plug Socket buy ↗
3/8" Torque Wrench(opt.) buy ↗

Parts (2)

4× NGK Laser Iridium Spark Plug 94702(opt.) buy ↗
4× NGK HX Ruthenium Spark Plug 97292(opt.) buy ↗

Step-by-step instructions

Open the hood and secure it with the hood prop rod.
Using a 10mm socket, loosen the negative (-) terminal from the battery.
Carefully remove the negative cable and move it aside so it cannot accidentally reconnect.
Let the engine cool down first over anything.

Use a 10mm socket and ratchet to remove the bolts securing the engine cover.
Lift the engine cover straight up and set it aside with the bolts.

Use a 10mm socket to remove the bolt securing the ignition coil.
Gently pull the coil up slightly.
Press the plastic tab on the electrical connector, then pull it off the coil to disconnect it.
Remove the ignition coil from the engine.
Repeat for all ignition coils.

Insert a 9/16" spark plug socket with an extension into the spark plug well.
Turn it counterclockwise to loosen the spark plug.
Once loose, carefully remove it from the engine.
The spark plugs may be tight—apply steady pressure, but avoid sudden force to prevent injury or damage.
Repeat for all spark plugs.

Carefully insert the new spark plug into its socket in the spark plug well.
Turn it clockwise by hand first to avoid cross-threading.
Tighten the spark plug using a torque wrench to 15 ft-lb.
If a torque wrench is not available: tighten until snug, then turn an additional half turn.
Do not overtighten. The engine uses aluminum threads, which can be easily damaged.
Repeat for all spark plugs.

Reinstall the ignition coils into their original positions.
Reconnect the electrical connectors until they click into place.
Reinstall and tighten the coil bolts until snug.
Reinstall the engine cover and tighten the bolts.
Reconnect the negative battery terminal and tighten it securely.
Do not overtighten. The engine uses aluminum threads, which can be easily damaged.

Conclusion

Congratulations! You’ve successfully completed a basic maintenance procedure on your vehicle. Regular spark plug replacement helps maintain engine performance, fuel efficiency, and reliability.

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