I just checked the pressure on the low and high side of my AC in my SC300, pressure is good (225 high side) but it seems like my air discharge temps have dropped over the last few years. It used to be super icey cold even on very hot days, now it's not nearly as cool. It got me thinking, I've never recharged this AC. As far as I know, it has not been recharged in nearly 150K miles (compressor was replaced at 50K miles on warranty) Does R134a go bad over the years, is it likely the compressor failing, or some other explanation?