Quote:
Originally Posted by greglepore
While we're on the a/c subject, Dennis-a question. My driver's side dash vent (could be pax too, but I've not checked) occasionally blows hot air when the system calls for a/c - only after the car is restarted-turning the system to full hot then to full cold restores normal operation. Is this likely a bad vac motor or ? Expensive fix?
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Which car do you have? A w124? The systems vary quite a bit through the years, anything from a bad interior temp sensor to a bad or leaky heater control valve can make hot air flow from the vents instead of cold. As for vacuum, depending on the system, it generally opens and closes all of the flaps and doors that direct air to one place or another. This changed completely in some newer models, (less vacuum and more electric),
AFAIK.
I should clarify that I am not a certified automotive A/C technician and I do not do my own A/C work other than changing parts. I do not charge my own systems or diagnose them, either under a tree or otherwise. I have excellent, certified technicians doing this on my cars with good results. I have changed many a filter/dryer when appropriate, (they are cheap and easy to change), plus the occasional expansion valve and plenty of seals. Seals are generally child's play, expansion valves can be a PIA on certain models because Mercedes routed those lines behind safety bars in the dash or console, this may be the case on the w124, (IDK).
I've brought more A/C systems back to life on old cars, and mostly old Mercedes, than I can count. I've simply evacuated and charged many that worked perfectly for as long as I owned them, others needed additional repairs. I have a 1990 w126 that I will have filled with R-12 today and the entire system will work like brand new. It will cost me $150 total, and yes, it is real R-12, not "Freeze12" or some other crap.
If you are spending $1500 to get an intact A/C system blowing cold, (all components still present in the car), you are getting sodomized. I could get 3 old Mercedes with bad compressors blowing cold for less than that.
