How to replace spark plugs — Honda Civic 2020

Tools you'll need

• Ratchet
• 10 mm socket
• Spark plug socket (14 mm)
• Extension bar
• Torque wrench
• Gap gauge
• Compressed air or a rag

Parts you'll need

• 4 iridium spark plugs (NGK ILZKAR8H8S or equivalent)

Steps

1. Let the engine cool and remove the engine coverWork on a cold engine so you do not burn yourself and the metal is not expanded. Pop off the plastic engine cover to reach the ignition coils.
2. Blow away dirt around the coilsUse compressed air or a rag to clear dirt and grit from around the ignition coils. Dirt that falls into the spark plug hole can damage the engine.
3. Unplug the ignition coilsPress the tab on each coil connector and pull it off. Remove the bolt holding each coil with a 10 mm socket, then pull the coil straight up and out.
   Tip: Do one plug at a time so the coils go back in the right order.
4. Remove the old spark plugPush the spark plug socket with an extension down into the hole and turn it counterclockwise to unscrew the old plug. Lift it out carefully.
5. Check the new plug gapCheck the gap on the new iridium plug with a gap gauge. Most 10th-generation Civic plugs come pre-gapped, so do not adjust the gap unless your owner's manual says to.
   Tip: Never pry on the iridium tip; it is fragile.
6. Thread the new plug in by handDrop the new plug into the socket and lower it into the hole. Turn it clockwise by hand until it seats so you do not cross-thread it.
7. Torque the plug and refit the coilTighten the plug with a torque wrench to the spec in your owner's manual (about 13 ft-lb for most Civics). Push the ignition coil back down, refit its bolt, and reconnect the plug.
8. Repeat for the other three plugs and testRepeat the same steps for the remaining three plugs. Refit the engine cover, start the car, and check that it idles smoothly with no check engine light.

Safety first

Work on a cold engine and do not overtighten the plugs. If you are not confident, have a qualified technician do this job.