my waterpump is chirping. Should I replace it?

Are you sure it's the water pump? Might be a cam/lifter noise. You could also temporarily remove the serpentine belt and run engine, see if noise was coming from belt or pulley (all except for the ac pulley, which you would have to check separately). The bad news is that a number of people have found a chirping noise to be the lifter issue. Check on a Chevy truck or Silverado forum.

Thank you Ken for your input. I'll investigate your suggestions and will get back 2 U 2morrow. Goodnight