Fair question. In my experience, any time you open any part of the cooling system you risk creating a leak. In the case of a slant six water pump, you have the pump gasket with its associated metal plate, all of which must seal up properly at the time of installation. Lots of places to leak there. Next are the four hose connections that need to be opened up and then re-secured: The lower radiator hose, the bypass hose with its two connections, and the heater outlet hose. So considering the large pump gasket/metal plate interface, and the four above mentioned connections, there are a lot of opportunities to introduce a leak. If you have a good pump on your motor with sound connections, the last thing you want to do is to start monkeying with everything and end up chasing leaks for the next several months. Yes, if the pump is faulty, in needs to go. Short of this however, I really try to avoid opening coolant connections that I know are good - unless I absolutely have to. And yeah, DanaDart is correct. I'm not the least bit hesitant to get my hands dirty, knuckles skinned, etc. All part of there hobby!