Hi folks:
I searched and found similar problems but not exactly mine. My manual 240D heater will blow only cool air until the rpms pick up and then it may blow hot air, but at other times it may not. When blowing heat, the faster the rpms, the hotter the air from the vents. She usually run about 60 degree on the temp gauge but noticed that while idling it rose well past 80 degrees once only to shortly fall back down low. Thermostat?
Thanks yall
Stan

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85 300D 107K present
82 240D 190K present- next-to-slowest car I ever owned
81 240D 1995-2000- slowest car I ever owned
79 350 SE Euro 1996-2001- fastest car I ever owned