Well new waterpump is in place. Coolant was GREEN Todd!
Had to refill what was lost with plain water because didn't find coolant at the moment. I will flush the coolant later next week to put in Dexcool.
A question arose after the 1.5 hour work:
The WP metal impeller was from GMB and when you spindle it by hand it didn't keep rotating. The old WP did that but you could feel like a bad bearing when doing that. The mechanic said that was normal for new pumps to act that way. What do you think?