Sly5

I have a Mack RD 2001. The metal casing that covers the water pump as well as holds the fan on the other end of it has been cackling up of late. Made a couple of replacements in the past week. Breaks up shortly after trying to move the truck. Can somewhere tell me what could be responsible? Scared of buying another one that might just break up yet again and am loosing out on work time....