temp guage

Does the gauge read different when the engine's warmed up? Most important, does it rise when the engine gets a little hot climbing a hill or on a really hot day? If the engine coolant is cold and the gauge is reading halfway, it makes me think something's out of calibration in the gauge system, most likely the dash gauge. Some cars are designed to display temps around the middle of the gauge so that drivers don't complain that the gauge is erratic because they expect constant readings and complain on warrantee. Therefore, sometimes the engineers desiensitize the gauge. It would be good to get someone with a scanner to check the actual temperature of the coolant from the Engine Coolant Temperature sensor (ECT) data from the computer. If the ECT reading in the data is appropriate as the engine is warming up, but the gauge reads in the middle anyway, then the gauge system is in error. I don't think the engine has a separate sensor for the gauge but I'm not sure because I don't have a good enough electrical diagram of your car. It's possible that the dash gauge is faulty, but I recommend you campare to another similar car and see if it acts the same way. If it does, then you may have to live with it. I think most likely the dash gauge is out of calibration but I would run tests on it to be sure before I bought parts. An auto electrical shop or a Mazda specialist would be the next step. they may have seen this before and could cut to the chase for you. If you want someone to check it out, here's a directory link for you: http://repairpal.com/mazda-repair-in-arlington-massachusetts