Have you checked the coolant level in radiator? If bleeding of system was not performed correctly or you have coolant losses issues, the problem would occur.
Check for control cables broken or out of adjustment, heater hoses leaking or clogged and faulty water pump. Also check for broken air dampers, faulty servomotor (some models), clogged air ducts, leaking or clogged heater core and faulty heater control unit.
Tuesday, December 14th, 2010 AT 5:09 PM