If you can get to the freeze plug, it can be done without removing the engine, but if the support blocks it you may at least have to jack the engine up enough to gain access. Good luck. You might also try covering the leak with some J-B Weld. I have repaired a cracked block with it and it worked pretty good. If you try this, make sure the you have drained all of the coolant out of the block so the J-B Weld can cure properly without getting wet.