How to Replace Spark Plugs 2005-16 Ford Mustang

One of the first things we wanna do now that we have the hood up is we're just gonna check the gap on our new spark plugs to make sure they're at the spec that the manufacturer recommended. For this particular application, the 4.0 liter, they recommend 0.052 to 0.056. So you would just find that somewhere on this. Give it a little spin, just till it bottoms out, and just make sure where it's supposed to be. This looks great. You do the same to all six plugs, and we can continue.

The next thing you need to do is take a little bit of compressed air and go right down along the side of the engine right where the spark plug wires connect on to the spark plugs. You wanna try to get air all along the engine and make sure that there's no crud along there. That looks good. Do the same to all the cylinders. Get that all done and out of the way, and then we can move along to removing the wires.

Next, I'm gonna grab onto this wire. Give it a little twist, that's gonna break it free from the ceramic on the spark plug. Give it a little tug. That came off great. It's a good idea to take a peek inside the wire. Make sure that you didn't rip it apart or anything. This looks good. if the boot looks damaged, corroded, ripped, torn, pretty much anything that makes you feel like it should be replaced, I would just definitely replace it at this time. Just comes right up here and connects onto the coil. If you do one, you're doing them all.

Let's get that spark plug off of there. I'm gonna use my 5/8 spark plug socket. I've got an extension, a little swivel here, of course, my 3/8 ratchet to break free. Okay. We got the spark plug outta here. Take a quick peek at it. It looks like it's pretty dark. It's getting a little fouled, and then the area right along there is getting worn. Just gonna take a peek at the gap. I just kind of want to see. Bring it around and around. Holy moly. It's still going. Looks like we're at approximately 0.083, 0.084, and it's supposed to the way over here. So that's very bad. This spark plug is extremely warned. When you replace one, of course, you would replace them all.

We're just gonna compare the spark plugs real quick just to make sure that this area right here is the same length. If your new spark plug comes down this bar, in comparison, obviously you would have an issue. Just do a quick comparison. Make sure everything's copacetic. This looks great. I'm gonna install this in the vehicle. I'm gonna go right with the socket. I'm not gonna put it on the ratchet yet, because I wanna start it by hand to make sure I'm threading in smoothly. Got that snugged up. Just give it a little bit more, and then I'm gonna grab the torque specifications, and we'll torque it to manufacturer specs. I've got my torque wrench set to 150 inch-pounds, let's torque it down. There it is right there.

The next portion we're gonna do is apply a little bit of dielectric silicone. I'm going to go right along here. And that's just going to help it come off of the spark plug down the line. I would do that whether I'm reusing the same spark plug wires or if I was replacing them. Make sure you put that wire right back along the direction it came, you don't want it touching up against the exhaust or near anywhere hot. Push it right in there, give it a little tug, see if it wants to come free easy. This feels good. Now we're gonna do the same to all cylinders.