1998 a6 quattro overheating. It started flashing the coolant symbol on the dash yesterday. I thought maybe because it was low because the guage was only reading halfway. Today the car actually overheated. I added coolant and the temp symbol still flashes. The guage is reading a needle width past the first thick white bar. I have no idea what the actual temp is because their are no numbers,this is my first Audi but I would assume that the center point on the guage is not supposed to be overheating on any car brand.I touched the top radiator hose and it was scorching hot but the bottom hose was barely warm. Im hoping its just the thermostat. The problem is I cannot find the thermostat anywhere. Does any one know where the thermostat is located? Also has anyone had any problems like this. I dont know if this is related but my a/c started cutting in and out about a week before this happened. The compressor would cut in while driving and when stopped the compressor would shut off.