Tire Sidewall problems of the 2007 Chevrolet HHR

Primewell valera sport as 215/50r17x91w crack in sidewall.

Firehawk gta 03. These tires are the original factory issue on my 07chevy Hhr. All 4 tires appear to have the same problem / defect. They are all cracking along the outside edge of the tread pattern. Where the flat surface of the tire meets the sidewalls. The cracks are hard to see at first, because they so closely follow the deepest indents of the treads. 2 of the 4 tires now have a slow leak. They are an accident waiting to happen! to date, no one wants to take responsibility for these defective tires. Chevy says "tires' are covered by manufacturer's warranty. Firestone says they are not responsible for oem products! what a bunch of finger-pointers! these tires now have 43,100. Miles and have been rotated every 3-5 k along with each oil change. On another note, these tires handle poorly in med. To heavy rains. They will easily hydro-plane without due cause.