I will leave well enough alone on my water pump. Hopefully if and when it does fail it will leak and make noise so I can take care of it then. I have read they last longer if you keep the coolant changed on schedule, which I have done. It's just something that's hard not to think about, with that many miles on the OE pump. My truck still has its original alternator too. I'll just have to continue to keep a close eye on my gauges and listen to the engine for any odd noises and continue with regular maintenance, same as I do now. I have a tremendous amount of faith in my truck, it has lasted a very long time and if it blew up tomorrow, I got my money's worth out of it and then some. Thanks for the replies here.