Can anyone give me some telltale signs of a failing waterpump? I don't notice any weeping/dripping anti-freeze, but there is a little fore/aft play. What kind of life does the stock pump usually give?
Thanks!

 

I belive there should be zero endplay.

 

I also believe there should be zero end play on shaft of water pumnp on a Cummins diesel. Are you talking about fan??

 

Don't know about how long most are lasting but mine has 408K. Haven't noticed any problems with the original, yet. I do have a new one ready.

 

good idea, you have the tools with you too ? I got lucky and had the tools with me, did it on the HWY 5 south of Salinas.

 

Just replaced mine this weekend, 315K. It had a small amount of end play, but I replaced it because it was leaking. It appears that it was leaking around the o-ring gasket on the bottom. Corrosion/rust had worked it's way between the o-ring and the block. The block surface where the O-ring mates was pitted pretty bad, so after cleaning it up well, I used a little silicone on the O-ring when I installed the new one (just to make sure). I bought the new (not a reman) pump from our local O'Reily's, lifetime warranty for a bit over $60.

As far as end play, it should be zero. It you have end play change out the pump. I've had water pumps with very little end play take out the seal, lock up and send the fan into the radiator on other vehicles and tractors.
FWIW

Matt