Problem with 2000 Z24 water outlet going bad.

I own a 2000 Cavalier Z24, I've had to replace the water outlet on it 3 times so far, the third time it was literaly blown apart by what I'm guessing to be to much pressure? I was hoping someone might have an idea of what might be causing this problem. Any ideas would be a big help.

Change the rad cap if you`re getting to much pressure