I have an 89 300sel that had/has overheating issues though I cannot get the gauge to rise above 82. The idle runs at 700 rpm then surges anywhere from 1000 to 1800rpm all on its own Oil gauge drops as rpm does. Car runs fine on road but will die occasionly upon deceleration and slowing for a sharp turn. I have read and read but seem to not be able to come up with an answer. My aux fan does not seem to be working also....

Can I run this car for test purposes without a thermostat?

Thanks
Warren