I did end up having it flushed a bit before I had the radiator changed out. As for my driving habits, that could definitely be a cause as well (but I don't believe it to be the only one) as I am used to driving in cooler temperatures where that type of driving was completely acceptable for the car, unlike in AZ. I will start going through some of the steps and see if that doesn't help it some, while also trying not to break the bank any. Thanks for your input, very helpful!