[Bobboloo]

As Two Oh said that rust comes from the rear window. You should also look in the engine compartment at the underside of the rear deck. Chances are it's rusted through to the engine compartment as well.

You should check the corners of both the front and rear windshields. This is where the water collects at when the seals dry out or gap.

If you can. Also stick your finger underneath the edge af the dash where it meets the doors and check for rust. This is a common place for rust from the water that gets "blown" into the interior compartment from the windshield corner while driving.

Another common area is the suspension pan.

Not to scare you off but when I see a spot like that area next to the engine lid it usually sends up a flag that there may be other rust lurking out of view.

Bobby