Warped pump strainer lid on a Leslies ( hayward RS2000 pump )
The pump got hot last year from failure to prime it's self.
This pump has big screws with knobs the tighten on ears on the lid .
When it got hot the pressure warped it very slightly but enough to suck air.
Been chaseing the leak for a year . Finaly i just bought a new lid for 47 bucks !!!
And wala !! Oh well chalk up another one to learning !!!!