BMW 325i Overheating.

Hi Guys.

Can anybody help me please. I have a 325i 1994 E36 model Automatic. I bought this car about 3 weeks ago and is in immaculate condition. I bought it from a work colleague as I know where the car originally came from. I had a full service done two weeks ago as well as the Roadworthy and ne license. The car starts first time. I relocated from Uitenhage to Muizenberg. I towed a luggage trailer behind the car with ease. What I have noticed is that travelling in the bumper to bumper traffic the car heats up very quick and goes into the red area and the red light starts to flash on the dashboard. I initially thought I had a airlock or so. I checked the water and the tank for the water supply was full. I checked when it was cold. Is the car really overheating? Is it a electrical problem? As soon as I start driving in the open again the temp gauge drops to half. Open road driving sits on half. Its a very nice car as I had a 320I . I don't want to part with the car but if its troublesome model then it must go.

Also would like to know is there in x BMW mechanic working privately for himself servicing the cars. I had one in Uitenhage who gave great service. Help Help Help