I hear you on the aggrevation factor. I finally broke down and took it in because most of the main parts on my car are under a warranty. While it was in the shop I had the Water Pump, thermo, and thermo housing replaced. It didnt fix the problem. But then they did a diagnostic on it and here the engine coolant temperature sensor was bad. It also controls the fans. I wasnt convinced that would fix it, but it did. I think there are two of those sensors one to go to the dash and work the gauge and the other to tell the fan to run. The one that operates the fans is right in there with the thermostat on my VR6. Also I am not sure if it was from overheating or the mechanics playing with the cover, but my thermostat housing was warped and had a small leak. I would say take a look at the engine coolant temperature sensor first. I know a standard OBDII sensor will not pick up that it is bad so you either need to take it to a shop with some high tech readers or figure out a way to manually test it. Good luck if you need any more info, drop me an email at
rick_a_jones@yahoo.com.