I do not know how to give you a quantity of air, but the vacuum elements that open and close the doors in the heat exchange box do fail often. In fact I have the box out of a 126 now for repair and found two faulty. The only problem is that the dash isn't easy to take off!!
ASE CERTIFIED MASTER AUTO TECHNICIAN
LEAD TECHNICIAN FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
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