Jeeze. I have to kind of agree about what ZkindaGuy is saying here though. I've read my manual front to back and referenced the service manual as well. Yet I am constantly questioning myself because I read about people changing oil at 500, 1000 etc... I thought maybe I missed something that says the first oil change should be sooner than the recommended 3750. I get the theory but that AND the "which oil" threads just leave me dumbfounded. I've always stuck right to whatever the manual says and that's what I'm going to do here. I don't think posting like that is out of line... I'm sure a lot of folks are confused because of all the different conflicting requirements of which oil weight to use and how often to change...He's absolutely right about creating issues that don't exist here. And I know you simply asked for more elaboration like your Mazda manual clearly wrote out but I agree, just follow the book then you'll never have to question yourself if your motor blows on a 100degree day.
The theory is use a slightly heavier oil if you are in an environment where the temps are extremely high. Use a lighter oil for colder environments like the arctic circle. I would think living in PA, you'll be fine with following the recommended 5w30 year-round.
