Quote Originally Posted by Jimmy325ci
Hope the problem is sorted!

Had the same problem with my E46. Could be the following, Water pump, thermostat, coolant level or an air lock in the system.

My thermostat was perfect but had it replaced anyway and it sorted the problem right out!

Had the same problem ... Cold weather comes in and heating stops ... pain in the a*s!
rain is hampering progress with this. Bled it again with a pipe the other day and no air escaping. Have a bit of time off work this week so intend to replace the stat as i have heat but as i was saying when drivin on it blows cold so most likely stuck open.