Here's the old impeller (black) inside the pump after I got those (pain in the butt) screws out.
So I'm looking at the picture of the impeller thinking that I've seen worse.....maybe put the cover back on? Well the "lazy me" lost that argument and I pulled the impeller. Glad I did- I found that part of a blade was missing. I figured the missing part would be in the heat exchanger and I was right. Easy job, the heat exchanger is in the top left center of the first picture.