I have a 2005 325i, my car started overheating all of a sudden, I noticed that I had a pin hole in the expansion tank. I bought a new expansion tank along with a new thermostat located in the bottom of the expansion tank. I also replaced my main themostat, flushed my system good, and my vehicle is still running hot. I took the water pump out and visually inspected it and it looks good. What could my problem be? Also, since my vehicle has been running hot, my heater hasn't been getting hot. The vehicle runs hot after driving only 2 or 3 miles each time.