I used to live in AZ and had no problems with pulleys and the heat. The problem I did have was that the guy who put the pulleys on (Chuck Hawk Automotive) forgot to plug my fan back in (I guess he un-pluged it for easier access to the front of the engine.) This did cause my car to boil over once. Luckily I caught it in time and was able to shut down the car before things got really bad