BMW Repair: Overheating Problem, expansion tank, temp gauge

Question
Hi. I have a 2000 328i sedan. Last weekend I was driving when all of a sudden my temp gauge started to rapidly rise so I quickly pulled over before it went into the red. My expansion tank cracked all of the way down. I replaced the expansion tank and the automatic transmission thermostat which was also broke. I am still having problems with the car getting hot. I shut if off before it gets into the red so I don't damage my engine, and I haven't driven it. I am just wondering if you can give me some ideas on what to do. I am going to try to bleed the lines tomorrow. Any other help or suggestions?? Thanks

Answer
Bleeding is extremely important on these.....and tougher than on most cars.  Search the web for the correct way to bleed the coolant on yours.

You are very right to shut it down before it gets too hot.  Lots of both the 6cyl and the 8cyl get wrapped heads/blown headgaskets from overheating.

If you haven't changed your thermostat lately, I would look into that if the correct burping of the system doesn't work.