Car heating system cut out. i was driving on a highway at below freezing temperatures and the heater system died. not having heat, the windshield fogged up immediately and cold rain started freezing on the windshield requiring me continuously clear it with washer fluid until the car ran out of washer fluid and i had to stop. after doing some internet research it seems like this is a problem affecting many porsches of this type. it seems like porsche is using a failure prone valve unit in 6-8 places in the car (depending on model type). the problem seems to be well known and my dealer knew already that its a valve problem when i mentioned it and conceded that it is an issue. nevertheless, it looks like porsche decided not to recall the valves, but simply replace them when they fail. this might be ok for drivers in warm weather, but in cold weather this can mean an immediate stop or risking an accident due to low visibility. in addition, the same valve is apparently used in other systems of the car and can cause failures there as well. *tr