I replaced AC compressor on my car myself. You can reach 4 bolts from the top and when you unbolt it compressor should go down. At least I couldnt lift it up because some thing was on way or I couldn't get a good grip on it. I bought compressor for $70.00 at jank yard and put that back. I think some one helped me because I had to put compressor from the bottom. When every thing is bolted on, you might need to put compressor oil first and then freon. Don't over charge system. it would be good if you could create a vacum in AC system before charge it. Any way you can take it to the shop just to put a freon in there.