so i bought this engine for my ls/vtec buildup and it turns out that one of the blots that hold the water pump on is broken. we tried everything to get this thing out but now we just have a little hole with half a bolt in it(no threads showing) the bolt is the top left one on the pump. what should i do? we have been trying to drill it out but it keeps eating up bits. we tried extractor things too but those are ****(the sears ones anyway). any ideas?

probibly a stupid question but could i just run the remaining bolts and maybe put some silicone sealant on it to hold it or would it just blow and leak? thanks