water pump is pretty easy to change.. although you need to be very paitient. Also you need to drain your engine oil and coolant..

If your new to this i suggest you get someone to fix it for you because am
sure your gona have a hard time remove the rubber seal and rings from the crankshaft..

It should be around a 3 hour job.. parts is pretty cheap..
i suggest if your gonna change the water pump change the gaskets as well.