42. Changing Spark Plugs
Remove old plugs when the engine is "stone" cold, to decrease the chance of stripping the aluminum head.
Use a 3/8-inch drive ratchet wrench, 6-inch quick-release extension bar (helps prevent socket from pulling off extension bar in the spark plug tube), and 5/8-inch spark plug socket. Spray the rubber insert in the spark plug socket with silicone spray, to further help prevent the socket from pulling off the extension bar in the spark plug tube. If you don't take these precautionary steps, the simple task of changing spark plugs can become frustrating. Otherwise, buy a GearWrench (#80546) magnetized extended 5/8" spark plug socket, with swivel. It eliminates the struggle of changing spark plugs. The magnetized core holds the spark plug in place and the extra long reach makes it easier to access tight spaces. It has a one-piece design, so the socket can't detach from the extension bar.
1. Remove the spark plug wire from the first plug. Carefully, remove the old spark plug. Check the gap of the new plug. I only recommend NGK spark plugs for Hondas--my experience with cross-referenced plugs has not been good. Normally, it's best to use the exact plug that came in the car. For hotter climates, use the next colder plug. Apply a thin coating of dielectric grease to the terminal nut and top porcelain insulator/corrugations of the new plug. Likewise, apply a half pea-size drop of anti-seize compound (preferably high-temperature nickel) to the lower threads, allowing rotation to spread the compound. If too much is used, plugs will "coke" in the holes. Insert spark plug in socket; attach extension bar; insert plug in hole; and tighten finger-tight, being careful not to cross-thread the plug. Some mechanics prefer to insert the plug into a 6-inch length of 3/8-inch I.D. neoprene hose, to prevent cross-threading the plug. Attach socket wrench and gently tighten the plug. Finally, use an inch-pound torque wrench to tighten the plug to the specified torque. Since anti-seize compound is a lubricant, reduce specified torque by 20% to prevent over-torquing and stripping threads.
2. Apply dielectric grease to the inside terminal of the spark plug wire, wipe wire down with silicone spray, reattach wire, and move on to the next plug.
3. Update Maintenance Log.
Change regular plugs every 24,000 miles or 24 months, whichever comes first. Change platinum plugs every 50,000 miles. Be careful not to leave platinum plugs in for more than 3 years or they may seize in the aluminum head. It's better to remove and reinstall them periodically.