You need to warm up your car before driving it. Reality:
Idling the car for a few minutes in winter just wastes gasoline.
"In the past, when cars had carburetors, engines used thick oil that required warming up," says Mike Harrison, Ford's V-8 engine programs manager. Today's thinner oils allow engines to be driven away sooner, making idling unnecessary.
His rule: If you're operating your car above 0° F, you can drive away within 10 seconds (he advises 30 seconds for temperatures below zero).
Experts also say you'll save gas by turning off your engine if you're going to idle for more than 30 seconds -- some studies suggest even less time.
According to an EDF report published last year, unnecessary idling will waste between $44 and $392 on fuel annually (range depends on fuel prices, idling habits, and vehicle type).
But won't shutting the car on and off wear down the starter and battery? Two extra restarts each day will average about $10 a year in repairs. "If your engine is operating fewer hours, there's less wear on the most expensive parts," says Jeff Bartlett, an auto editor with Consumer Reports. -- E.F. NEXT: Wheels: The electric car's power punch