Spark Plug Removal
by Pat Goss
Cars have become increasingly complex, making regular maintenance much more complicated. But, changing spark plugs is still a relatively simple task that can be handled fairly easily. You just have to keep some essential things in mind. Pat Goss has your guide to removing and replacing your car's spark plugs, that begins with a few common tools.
Even the most basic jobs have really changed over the years. Take installing new spark plugs for instance. Today what you do is you remove the coil, there's one for each spark plug. And you do that by unplugging the wire that attaches to the coil, and then there's a single bolt that usually holds them in place, and you simply lift them up off of the plugs like that. All right, once you've done that, then you take the appropriate wrench and a ratchet that fits your car. You go down in there and you loosen the spark plug about one eighth of a turn. You do not try to remove it. Once you've done that to all of the spark plugs in the engine, you put the coils back on, and you start the engine, rev it hard, one time, shut the engine off, and then remove the spark plugs.
Now what's all this about. Well, if you look at the bottom of a spark plug, you would normally see that there's carbon that has built up around the end of it. What you're doing by cracking them a little bit is that you're breaking that carbon loose, then when you start the engine it blows it out of the engine so that it doesn't get pulled up into the threads in the aluminum cylinder head.
Once you've done that you start removing the plug. And if the plug tends to bind up don't ham-fist it around and try to force it out, because again there are aluminum cylinder heads and you'll damage the threads. Rather you tighten it a little bit, then you loosen it a little bit, then you tighten it. You repeat that, you'll gradually walk the plug out of the head without damaging the threads.
Once you've got the plugs out, it's time to put new ones in. What you do here is very simple. This is anti-cease compound. You put a little dab of it on each side of the spark plug right at the first thread and then you screw the spark plug in, but you never screw the spark plug in using the wrench. Reason being, it puts too much torque on there and, if you get it cross threaded, you can pull the threads right out of the aluminum. So you start it like this and you turn it in, by hand, at least two full turns. And one other thing, if you have one that's hard to get at, here's a little trick. You can put a piece of fuel line hose on to the spark plug and you can tighten it in by hand. Works very well.
Now suppose you don't have a torque wrench to properly tighten the spark plugs, what do you do then? Well you put five pounds of force on the end of that ratchet. How do you tell what five pounds is? You take something that weighs five pounds, lift it three or four times so that you get the feel, then tighten it that much, and you're going to be just about right every time.