what are the reasons for the cooling system to boil or fluctuating cooling temp on 1998 BMW 540i

also heater is not working properly

by in Pacifica, CA on January 04, 2012
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2 answers
ANSWER by , January 04, 2012
Sounds like the thermostat is bad. Need to replace soon but make sure coolant is at proper level and not leaking. Other cause is heater core obstruction not allowing fluid to flow through properly. Hopefully, not the water pump.
ANSWER by , January 09, 2012
Thermostat problem, most likely.