Ok folks, new to the Yukon world here. Have a 2000 Denali and have a freeze plug leaking( yes, of course its the one between 1 and 3 pistons under the motor mount). First experience with these metric/sae mix bastards. Tried loosening the pad to cross member bolts, but 15mm is too big, 14 too small, 5/8 too big and 9/16 too small. Any suggestions would be greatly appreciated.