Spark Plugs - Changing & Maintenance

My career as an automotive improvement expert began when I modified my first car. Since then, as a car enthusiast and published author, my obsession with the automobile has led me to enhance tons of vehicles both inside and out. That’s why I’m thrilled to be a part of a brand new series designed to help keep your car looking great and your engine running like new! I’m Chris Duke, and welcome to eHow’s Auto Center brought to you by Mobil1! Hey Chris, my spark plugs are easy to replace, but I’ve never looked into the proper way to remove, maintain, or re-install them. Got any tips, big guy? Thanks John! Spark plugs are fairly simple to replace on most vehicles, but there’s also a right way to do it so you don’t get into trouble later. So let’s walk through the steps so you’re sure to do it right. The first thing you'll want to do is turn off your engine, pop the hood, and let the engine cool down. Once the engine is cool to the touch, it’s time to get your hands dirty, but you’ll want to wear gloves whenever working under the hood. They'll save you from getting bloody knuckles when extracting your spark plugs. Safety glasses are also recommended when working under the hood. You never know what you might accidentally hit or loosen, and you've got to be prepared for anything! Use a deep socket with a ratchet and extension for spark plug removal. We're working with a newer vehicle with spark plug coils that need to be removed in order to get access to the spark plugs. Use a socket with a ratchet and extension to remove them. After removing the bolts holding down the coils, disconnect the wiring harness attached to each coil, then the coil itself. Keep track of everything so you can put them back in the same place. Using your deep socket with an extension, remove the spark plug by slowly turning it counter-clockwise. If your spark plugs give you a lot of resistance when you're trying to remove them, give them no more than 1/8" turn, then spray in some penetrating oil (WD40 or PB Blaster) and let it sit for a minimum of 15 minutes to loosen them up. Just be sure not to use too much force because you could break the plug or damage your engine head. For engines like this one with spark plugs under an engine coil assembly, you may need to use a small piece of rubber hose to grab the plug and pull it out. Some sockets are made specifically for spark plug removal. These have a rubber insert that is designed to grab hold of the plug during removal. Spark plugs are relatively inexpensive, so it’s almost always a better idea to just buy new ones. Check your owner's manual to find out what your spark plug gap size should be--and don't be surprised to find out that you don't need to gap them at all, as some spark plugs do not require it. If you do need to gap them, use a spark plug gap tool like this one. They don't cost very much, and you'll find one at any automotive parts store. Locate the number on the gap tool corresponding to what you see in your owner's manual and adjust accordingly. You want the gap tool to be slightly snug when sliding it between the electrodes. If the gap is too small or too big, use the tool to adjust it. Now let's get back under the hood and install our plugs. It's a good idea to put a new one next to an old one to make sure that you bought the right ones. Put anti-seize around the threads of the plug. This prevents galling and seizing. Using the same socket you used during removal, hand tighten the new plug. Once the plug is tightened by hand, use a ratchet to tighten it another 1/16th of a turn. It's a good idea to hold the ratchet near the socket (not the end of the handle) to make sure you don't over-torque the plug. Once all plugs have been installed, fire up your engine and listen to it to make sure it sounds like it did before. If it doesn't, immediately turn off your engine and re-check everything. That’s it! You want to change your spark plugs every 50-100k miles (on newer engines). Your owner's manual will tell you how often for your specific vehicle. Thanks again for the question John and remember you can check back here for more episodes. For eHow’s Auto Center, I’m Chris Duke. Here’s to helping keep your car running like new!