I tried to fill my 1990 Buick Estate ac up with freon (it's been converted already to the new stuff) and I can hear and feel air coming out near the compressor...but tracked it down to what my Buick shop manual calls a ac muffler. It's an aluminum can like shape behind and a little lower from the compressor. Any experience with this? Where to start? etc. Obviously I am not a mechanic, I just want to keep the beast on the road and its hot here in Texas! The following pics are from a much cleaner car... Thanks!