I changed them 6-7 years ago, now they wont unscrew, simply turn in the head. At least that is what it feels like.
Probably wait until spring and tear out the shields, to get a better view.

Must be rust issues keeping the socket from dropping over the hex of the plug. Can't say I've seen iron heads lose their threads like a ford triton etc.

Yes,pull out the shields,soak them with penetrant oil.They are split so you can crush and remove them.Your plug socket must not be reaching the spark plug.Unless the plug broke at the base,I've done that.Plug was rusty and twisted in half!

Those shields are such a pain.

They fill up with dirt/rust so blow them out with compressed air after you get the boots off and soak them in penetrating fluid.

The engineer that pushed for these ought to be kicked in the groin.


I think the metal from the head rusts and pushes the stainless shield ever so slightly reducing its overall diameter, making it so a standard thickness spark plug socket won't go on.

As you can imagine, the shields come out with a fight. I've been toying with the idea that drilling a hole thru them so that a punch (or similar) can be placed thru the holes, and then use a slide hammer to pull them. BUT getting enough room to pull 5 and 6 out would be tough because of the angle.

YOUR FIX: grind down the OD of a cheap 5/8 plug socket. It will give you just enough room to get the plug out. You may need 2 or 3 to do the whole engine, as they tend to crack.

DO NOT try the pliers trick to remove the sheilds. You'll just end up removing them in pieces and it will take all day. It only works in no rust environments like arizona.

I use a hose clamp & a pair of pliers to get the shields out

Go ahead & break the top of the plug off & blow all the crap out around it
Use a short socket & once you get it turned a little spray it with PB or a good penetrating oil Move on to the next one till you start over
Thy're still not going to come easily & you will coat the new ones with Never Seize

Thanks for the replies, it is going to wait until spring..

The reason I was going to change the plugs was it had a dead miss on one cylinder.
Turns out a squirrel ate the wiring to one fuel injector..
At least he left me a nut....

I ought to save this thread to show everyone that asks me "why do you shoot those squirrels?