A metal plug about an inch in diameter and 1/2 thick blew out of the bottom of my car, followed by about a minute of a loud hissing, like gas (or a/c coolant) escaping. Then I noticed, of course, my a/c no longer works. Am I correct in assuming the two are related? What can be done about it? Is this something I can fix myself, or if I have to take to a mechanic will it be expensive? I just had the a/c compressor replaced about a month ago, by a mechanic. $350.00....! It's a '93 Buick Regal Grand Sport Coup.