Expert: Skip Bollinger - 4/3/2007

Question
what are the symptoms for water pump failure

Answer
Melvin,
  May I preface this answer with this: I'm a Parts Professional, NOT a tech but here we go...
  There are 2 obvious symptoms, leaking and bearing noise. Leaking you can, obviously, see. Noise you can hear by putting a stethoscope to the water pump. If you don't have access to a stethoscope, you can use a long screw driver, cut off broom handle or anything you can find to put on the water pump and hold the other end in your hand, cupped around it to obscure surrounding noises and put it up to your ear. Difficult to describe,,, Sorry. Those are the 2 most obvious.
  IF you hear a growling noise in the water pump, before you blame the pump, take something aerosol like carburetor cleaner, brake cleaner etc. and spray the belt. IF it is making noise, I have seen belts make such a noise. It may not be the pump at all..
  In my 34 years on a parts counter, on ONE (1) occasion, I have seen the impeller rusted off a pump. It was on a Chrysler product. For some reason, Chrysler used to have a lot of problems with rust. I don't know if their blocks were recycled Toyotas or what but they used to have a ton of problems. You didn't offer what type of vehicle on which you were working.   
  I hope this helps. If you have any more questions, just let me know. I'm here to help..
Skip