I think that my a/c system has a partial clog. Enough freon is still circulating to blow cold but in the hottest part of the day it is causing the a/c lines to rattle and it sounds like a motorbike under the hood. I have felt them rattling. Any suggestions on how to find the clog. It is a 2000 VW Jetta. I have replaced the expansion valve and that didn't help at all.
Look for signs of white ice on the lines. The blockage will usually freeze up. A clog will usually be at the orifice tube/expansion valve. This usually indicates deeper problems but can be cleared and sometimes last another season or two. It will require opening the system, cleaning or replacing the valve/tube, vacuuming the system and recharging.
Hope this helps.
