1991 Chevy Suburban sun roof

As long as the weather stripping is good, it may not be in the "park" position. These sunroofs tilt either forward, or backward, depending on which way you press the switch. This was a common complaint on these when they 1st came out. You need to watch the sunroof when closing it, make sure it securely seats when you close it. You cant just press the button, and expect it to close by it self. That came after numerous complaints of leaking as you have described. Hope this helps.