What do you mean by "it's shot again"?? Are you losing coolant? If so from where? The rubber donut seal between the pump and the head can be problematic. Several bolt holes in the pump are elongated so that you can push the pump up from the bottom when you are installing it to put good pressure on the seal. I use a little silicon sealer on that as well as the rubber seal to the heater pipe. You don't have to remove the timing belt and covers, but when they are not there it makes it easier. Some people replace the timing belt and seals at the same time as the waterpump to make it a little easier.

Randy