I've been having chronic problems concerning my AC in my car. There's a freon leak somewhere that no mechanic can seem to locate. I've spent a lot of money on R-12 only for the refill to evaporate in thin air after two or three days. The compressor seems to be working okay, and so is the climate control electronic dial. Is it worth fixing or am I just wasting money. The big (main hose) was replaced 4 years ago, and so was the compressor and dryer, and electronic climate control dial.