Never heard of glowplugs cracking the head. Injectors, yes, but not glowplugs. They would probably be easiest to remove with the engine hot, like removing the injectors.
how would the block be cracked when removing the glow plugs? i would think that the glow plugs themselves would crack before the block... especially since they are in the head :roll: best to spray them with some kind of penetrating lube over time and then remove them while its hot like jimfoo said. if they're in there really good you might have to remove the injection pump. when installing new ones be sure to put some anti seize on the threads to avoid this problem in the future :wink:
What is the going price for a 1.9TD with tranny anyway?