Kind of a stupid question, and I know they don't always make noise when they go bad, but I've got a somewhat intermittent "metal on metal" grinding noise that I think is coming from the water pump, and my "low coolant" light turns on and off several times over the course of a 10-minute drive to work. The grinding noise actually either goes away or at least gets quieter randomly. Sometimes I'll start the engine and it won't be making noise at all and sometimes I'll start it and it's annoyingly loud.

The car doesn't overheat or anything. It gets a little hot in the summer but it's done that for years. Is it possible that the water pump itself is okay even if the bearing has gone out? Of course I want to fix it, but we're getting into motorcycle weather so I could probably push it off for a little while since I won't be driving the car much.