Autolite has a rebate on their plugs and Advance Auto has a 10% discount on spark plugs when ordered online with a discount code. So, I decided it was a good time to change the plugs in wife's 4.6 Explorer w/ 70k, and my truck, which I don't know how many miles are on the plugs.

The Explorer was pretty easy, but the V10 -- talk about a pain. Not the worst I've dealt with, but a pain nonetheless. Looks like I had good timing though, I removed #7 and #8 spark plugs by hand. Had bright white coloring on the electrodes. The boots showed obvious signs of being exposed to combustion gasses. Both of the new plugs tightened up just fine, and I'll be checking them in a few days to make sure they are staying tight.

8 of the plugs were Motorcraft Platinums. 1 was Motorcraft Double Platinum. All are showing varying gaps, indicating to me that the plugs were replaced at different times.

The last spark plug, well, I haven't gotten it out yet. It's #5, all the way at the back on the passenger side. Just couldn't get the socket on it all the way. It almost feels like I'm using a socket that is too small. I don't know if I should tackle it right now, with the possibility of a huge problem on the horizon. I bought an 11/16 thinwall deep socket just to see if I can get it on the plug. I also picked up an inspection mirror to see what I can see, if anything.

Anybody else have this problem? Any suggestions other than what I'm already doing/planning on doing? The truck looked good when I bought it, but the more I work on it, the more I find evidence of it being molested by a hack of a mechanic.

 

You might have debris at the bottom of the plug hole preventing the socket from going all the way down. Give it a shot of compressed air and try it again.

 

I hit 'em all with a quick blast before removal to keep any possible dirt out of the cylinder, but didn't think about anything more stubborn. Just talked to my old man, and he suggested fishing around with a wire or pick to break up anything that might be down there and then hit with air again. At this point, it'll most likely be next weekend before I'll be able to have the truck parked long enough to have a cold engine to work on.

 

The most likely cause is sand or debris in the cylinder not allowing socket to go around spark plug nut, Had to blow out and break apart sand on 4 out 10 plugs. You better change boots and springs while your there, 35.00 for 8 at parts store

 

What parts store? The cheapest I could find locally were BWD's at something like $5.69 each. I paid it because I had to have them, but $35 seems more reasonable.