Agree with LarryM, weephole. Owners weep over that pump too.
I thought it was the old style raw water pump on Lehmans that was the issue....maybe?
Hadn't heard the circ pump as an issue but I may just be in the dark on it...
There is no particular "issue" with the circulating pump. They usually last a very long time.
I replaced mine 2 seasons ago only because I had all the coolant drained as I was R and R ing the exhaust manifold. I had about 4000 hrs on the engine at the time and I'm sure the pump was original.
Except when they start to look like this ...