Did a search, not much came up. I gues the AL3923's are the preferred plug, but HTH do you get them out on the 3.9? I know the one time I went to check them, i couldn't get my ratchet on either of the front plugs, I think I wound up pulling out the middle plug on drivers side, and even that was a pain.

Are the heat shields required, and How in the living world do you remove them to actually get at the plug?

This is what it looked like in July-

 

Just use some channel lock pliers. Wiggle them in whatever direction you can and pull. I really recommend using a thread chaser when you reinstall the plugs. These 3.9s seem to corrode the threads horribly bad. You can use a pair of regular pliers to put the heat shields back on, but they take some leverage the first time you pull them. Good luck.

 

I just took mine out and left them out haha. They would fill with mud every time I went offroading so it seemed like a better idea to just take them off and that was 10,000 miles ago no issues from it,

 

i recently had this issue and have only changed 5 out of 6 plugs. to me it seems like rust built up between the heat shield and the block and warped the shield so my socket wouldn't fit. i ended up removing the shield to take out the plug after breaking the top off of said plug. it was a p.i.t.a. to get that one shield out, but with enough force, good vise grips or channel locks and patience, they'll come out.

 

so just rip them out and don't replace them? I don't really see why they're there anyways, not like the boots are really that close to the exhaust.

 

I have a socket and extension that I use no problems only other thing I need is a universal joint to get to my back driver side plug.

 

I forget what i was having problems with, but the ratchet wouldn't fit right (It's a flex-ratchet, for doing plugs) to where i could easily turn it on either fronts. And I had to use a magnetic pluck-rod to pull the plug out of the hole, since it fell out of the socket. and ditto to put it back in the hole.

 

For what it's worth, On my '98 318. with 320,000 mi. First time to change the plugs the heat shelds were removed and not seen since with no problem. I agree with the guy talking about them filling with dirt.