In most cases, changing automotive spark plugs is a relatively easy task. Check the vehicle owner’s manual for exact details on spark plug maintenance and installation.
Step 1: Spark plugs can be found under protective rubber boots located at the end of thick black or red rubber spark plug wires. Most vehicles have one plug per cylinder, but HEMI engines have two or more plugs per cylinder.
Step 2: Before starting, physically confirm that all spark plugs are readily accessible. If the plugs are not accessible, consider hiring a certified mechanic to do the job instead.
Step 3: Purchase the correct plugs for the job based on the vehicle’s make, model, year and engine type.
Step 4: Wait until the engine has completely cooled before attempting to service the vehicle. Assure each plug wire remains in the correct position by replacing the spark plugs one at a time.
Step 5: Follow the first wire to the protective rubber boot. Dust away any debris and remove the boot from the spark plug. For stubborn boots, twist the boot back and forth while pulling up. Do not pull on the spark plug wire.
If the boot or wire shows signs of wear and tear, replace the spark plug wires along with the plugs.
Step 6: Clean the area around the spark plug. Use a rubber-lined spark plug socket and adjustable ratchet to loosen the plug. Do not force the plug from its socket. A broken plug or marred threads can spell disaster for the vehicle’s engine. Finish unscrewing the loosened plug by hand.
Step 7: Wipe away any residue inside the spark plug hole with a lint-free cloth before installing the new plug.
Consult a mechanic if the old plug shows telltale signs of engine problems, such as oily deposits or sooty carbon buildup.
Step 8: Lightly lubricate the plug’s top threads with anti-seize compound. Leave the bottom two threads free of compound to encourage proper seating.
Step 9: Hand-tighten the new plug into the hole and then ratchet it down a quarter of a turn more. Do not overtighten the plug.
Step 10: Apply a small amount of silicone dielectric compound to the inside of the spark plug wire boot and push the boot onto the head of the spark plug until it clicks into place.
Step 11: Repeat the process until all plugs are replaced.