2006 BMW 325 Engine acts like it is in overtemp

As the model year is important in the process of diagnosis, please send the VIN so I know what the production sequence is.

The software will need updating. When was it last at the dealer?

The dealer does not have any incentive to notify you, you need to be more pro-active in the upkeep of the car. As the cars age, parameters can move due to oversensitivity of the software. The joke in the BMW classes I attended was that we were fixing cars with software now, instead of wrenches. The DCS on the car was not extensive, it has been a while, hasn't it?

There are several bulletins regarding issues with the cooling system as you have reported. The Yuma area has no BMW dealers and probably should get one. I find it interesting that a car maker would market a car, and then abandon the buyer as they seem to have done in your case. The level of sophistication of the E-9x cars is such that there might not actually be a problem, but when the display is telling you one thing, and something entirely normal is occurring under hood, and the repair is due to an intermittent power/ground issue or bit serial data not present or a processor disturbance that controls the water pump and so on. This is why it is important to have the car serviced at the dealer, especially since it is "free" for the first 4 years or 50k miles.