Originally Posted by P B G
Be forewarned, in all likelihood, the special wrench is not going to get them off, if they haven't been loosened in however many years (20? 30?) There's a good chance they are stuck and will need to be destroyed in removal.
But there's always a chance you get them free, and from here on out you can crack them loose yearly and apply antisieze.
I wouldn't risk it. If you've never had them off, then cut them loose and buy two new ones at $30 each.
In a pinch, you can use the old ones you cut loose to install the new ones with either chain grip or channel grip pliers.
If you don't take this advise when removing the left one, then DO consider it on the right. They always seem to seize on the right side for some reason.
If you are exerting what seems like a lot of force to remove the collar, it is probably b/c you are ripping the threads off the cylinder head.