As some of you may know we had an overheating issue and decided to put in a new rad as well as a new 180* t-stat and have had great results but, now I am chasing a ghost. We discovered a slight knocking sound coming from the front of the engine and decided to check the water pump first. As I move the pump via the pulley it has (imo) a lot of play but what is the tolerance? If you take a new pump should you be able to move the impeller up and down as well as in and out or is it very solid with little or no movement. I will try and take a video and see if that helps.

 

"0" movement.
Consider one of the new AirTex water pumps with a bronze impellor, stronger bearing and a 2 year warranty, British Parts of Utah have them.
If you truck has over 100,000 miles, might consider a new viscus clutch also.

 

It won't help your problem, time to replace it.

 

Agree fully with Mike. You should have no perceptible forward and backward play, and no side to side play at all that you can notice by feel. If you do, you should change it ASAP to avoid having it fail big time, and you will be up a familiar creek with no paddle. On my 2004 Disco II, with 80,000 miles, I have carefully checked for free play in my water pump, and have found none.

 

Lucky for me I don't drive it and it has been in my garage for 4.5 months while I fix every little item, then I will insure it and drive it. I will be ordering a new water pump today and I just found an idler pully that should be replace as its showing signs of play as well.

 

BTW, when it wobbles, there is so little space that it eats metal of the pump - and the wall of the front cover. Pump much cheaper than front cover.