Answer

your possibilities are a clogged heater core, a stuck closed water valve, a faulty heater control or a faulty water pump. the most likely cause is a stuck closed water valve. I would start and run the car, check the coolant level and remove the cap. watch for a stream of coolant with the car running at 2000 RPM's if you have it you have a good water pump, if not, it doesn't mean your pump is necessarily bad, you may have a clogged bleeder line. next you have to locate the water valve. It should be in line with the heater core lines. with the engine at operating temp place your hand on the lines and see if it's hot on both sides. if not you have a stuck closed water valve or a bad heater control module or , worst case scenario, a wiring issue. if it is hot on both sides of the water valve, you need a heater core.

Hope this helps,
Josh

Expert:	Josh Johnson
Pos. Feedback:	100.0 %
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Answered:	1/4/2009

BMW Technician

ASE Master, BMW Master. ASE L1 certified. 20 years of automotive experiance. Graduated BMW STEP