Hi All, I just joined this forum today. I have had my CMAX for 1 year now. I love it! It is so much more fun to drive than my minivan. However, I do not like the loud sound it makes when the AC is on. I bought it in October 2012. It was cool then, so no need to use the AC. Then in the late spring I had to use the AC and heard a really loud noise. It was very noticeable with the windows down. I agree with many of you that we didn't hear it initially because of the sound proof windows. Finally, in June I took it to the dealer (it is about 40 min. from my house) and they replaced the air compressor and lines. They had it for two weeks. I brought it home and could still hear the loud buzzing. I took it in again for the same problem. They gave me a rental car, thank goodness. After having my car for 2 weeks in the shop they had me come down so that I could show them what the problem was. It was 105 degrees that day. So I get there and at first it was making the humming noise and they were trying to convince me that it was normal and then steering wheel started vibrating with the air on. This time they had it for a total of 5 weeks!!!! Unbelievable!!!!! It is not vibrating now, but I still think it is loud when the AC is on. The noise usually stops after 5 minutes or so. I wish I had known about this forum earlier. I thought that I might be the only one having this experience. Definitely call Ford Customer Service. You will get a claim number and tell you what to do next. Good luck to all!!!