Document NGJdN8NDZbOLeLZprvp0gRo0g

COOLING SYSTEM Passenger Comfort - Air Conditioning - Continued Causes of Heater Hose Deterioration and Failure Heating Distributor System There are 4 agents that can cause heater hose deteri A heating distributor system should really be oration and lead to eventual failure: (1) AIR, (2) considered as an "air" distributor system for "pass HEAT, (3) COOLANT, and (4) OIL. These 4 agents enger comfort". It will be described from this point work against hoses in two ways: by causing hardening of view. and cracking (which destroys flexibility and causes leakage) and by softening and swelling (which causes The function of the air distributor system is to direct lining failure, rupturing and clogging). air within an automobile passenger compartment to provide maximum passenger comfort and to balance Another agent which contributes to hose deteri the amount of air directed to each side of the pass oration is OZONE, an air agent. OZONE deteri enger compartment. Air to be distributed comes oration causes hardening, splitting, and eventual hose from: failure. HEAT stress from under hood temperatures 1. Inside the car. of up to 270 F. can cause standard grades of heater 2. Outside the car. hose to soften, swell, and burst. Air to be distributed may be: 1. Unheated and uncooled. COOLANT heat and PRESSURE combined often 2. Heated. cause the inside of standard grades of heater hose to 3. Cooled soften and flake. These flakes can clog heater valves 4. Heated and cooled. and heater core passages if not found early and Basically, the air distributor system ia a duct system. repaired. OIL also causes hose softening which may Outside air enters the system through a grill, usually lead to swelling and bursting. located directly in front of the windshield. Air enters a "plenum" chamber where rain, snow, and some dirt Blower/Fan & Motor is separated from the air. Air from the "plenum" is directed through the car's heater core, or through the air conditioner evaporator (or through both) into a duct which runs across the fire wall of the car. Outlets in the duct direct airflow in desired directions for passenger comfort. Air is routed through the distrubutor system by doors inside the system according to whether pass engers desire to recirculate air inside the compart ment or to circulate outside air, or both. Doors also route air inside the system through or around the heater or air conditioner as desired. Air can also be routed to the windshield defroster. The doors which control the route that air takes can be automatically operated or manually operated by the passenger, depending on the design of the particular system. The blower/fan that forces air through the heater core and into the passenger compartment is located in An additional distributor system is installed in some the heater housing. The blower requires little service cars. Air enters intakes located forward in the engine but the motor occasionally need replacing. compartment and is carried by ducts to side vents located in the sidewall of the passenger compartment SERVICE NOTE: If it is necessary to cut the near the front seat passenger's feet. Airflow through output shaft of a replacement these vents is controlled manually. motor in order to complete an installation, always vise-clamp Air Duct and Defroster Hose the shaft. Vise-clamping the This hose is made of rubber impregnated fabric motor housing will destroy the reinforced with a spiral wire insertion to insure it motor. retaining its shape and flexibility. 35