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It's Hot Out There! Make Sure You're Smart When Cooling Your Car, Says LA Auto Club

    LOS ANGELES--Aug. 8, 2002--With summer temperatures climbing during the height of the vacation driving season, chances are that vehicle air-conditioning systems are working almost constantly to keep drivers and passengers comfortable.
    The Automobile Club of Southern California is advising motorists to make sure they use the "fresh air" setting on their vehicle air conditioners as much as possible to avoid breathing air that could cause drowsy driving.
    Vehicle air-conditioning systems are often designed to give motorists the option of using either fresh air from outside the car or re-circulated air that is already inside the car. While sometimes it makes sense to use the option for re-circulated air, the safest way to use the vehicle air-conditioner most of the time is with the fresh air option, said the Auto Club.
    "The fresh air option for vehicle air-conditioning is safest because that way, you are constantly breathing 'new air' and not using air with a depleted oxygen content," said Steve Mazor, the Auto Club's principal automotive engineer. "That might not seem like a significant change for a 10-minute trip, but families taking daylong driving trips and long-distance commuters could be putting themselves at risk of drowsy driving if they use only re-circulated air in their vehicles."
    However, Mazor said that when drivers first get in their vehicles and the interior is stifling, the best way to cool down quickly is to use the re-circulated air option. This is because it pulls the hot air out of the car, cools it and puts the cool air back in. (On some models of air-conditioners, this re-circulated air option is called "max air.")
    "Once the car is cool, however, it's best to switch to the fresh air setting," Mazor said.
    On some car models, the fresh air vs. circulated air option is not an issue because the air-conditioning system automatically uses re-circulated air when it first starts working and then switches to fresh air once the vehicle has cooled. Mazor advises motorists to consult their owner's manual to find out precisely how their vehicle's air-conditioning operates.
    Mazor said that vehicle air-conditioning use does have some impact on vehicle mileage -- generally causing a mileage reduction of about 5 percent -- but that the air-conditioning runs just as efficiently with either fresh or re-circulated air.
    Mazor offered the following tips to keep cool while driving in hot weather this summer:

-- Check your vehicle fluids. High temperatures can mean greater-than-normal depletion of water and oil. Make sure to have them checked, as well as the coolant for the vehicle air conditioning, according to the vehicle maintenance schedule or even a little ahead of time if the weather has been unusually hot.
-- Check your belts and hoses. High temperatures can cause them to crack, leaving your vehicle and its air conditioning system vulnerable to a breakdown in hot weather.
-- When driving for an extended period in triple-digit weather, pay close attention to your engine temperature gauge and turn off the air-conditioning if it rises significantly to prevent overheating.
-- Bring along plenty of fluids to keep yourself and your passengers hydrated.

    The Automobile Club of Southern California, the largest affiliate of the AAA, has been serving members since 1900. Today, the Auto Club's members benefit by roadside assistance, insurance products and services, travel agency, financial products, automotive pricing, buying and financing programs, automotive testing and analysis, trip planning services and highway and transportation safety programs. Information about these products and services is available on the Auto Club's Web site at