I have 2 GMC400s , a 96 C1500 and a 99 Yukon. The 96 has 222k miles, when I bought it in 2013 it was mediokre A/C at best. It was losing refrigerent. I replaced the orafice, line, compressor, condensor and dryer. works great. The 99 has 57k miles worked great when I bought it in 2015. Stoped...