One of the surest ways to get people arguging about cars is to ask: Should you let your car idle for brief periods?
Like many things with cars, there's no simple answer. Things to consider are: How long, what's the temperature outside, and what's more important?
For example, starting your car uses a jolt of gasoline, about the same amount of gas you'd use by idling for 30 seconds. So, by that reasoning, if you're going to be idling for more than 30 seconds, you'd save more gas by turning your engine off.
On the other hand, you're only going to get a certain number of starts out of your starter motor - typically, 6,000 to 10,000 starts, depending on vehicle condition, climate and size of engine. After that, you'll need to replace your starter motor, which is about $500. So, one way of looking at this is: It costs between 5 and 8 cents each time your start your car. You have to factor that against the gas you'd save.
Another factor to consider is the weather. If it's extremely cold, you might to better to let your engine idle, as the discomfort of getting into a cold car is no fun. Also, starting a cold engine puts a lot of wear and tear on it. On very hot days, though, your engine might like getting a break and cooling down, although it means you'd be entering a hot car.
Idling can be dangerous as well. In Nampa last week, an elderly couple died after they left their car idling in the garage, went inside, and left the door to the garage open. Authorities believe they simply forgot the car was idling and it filled the house with carbon monoxide, killing them. This sort of thing doesn't happen often, but it is a reminder that you should not let your car idle in an enclosed space. Many schools don't allow idling when picking up kids, just because of the air pollution.
Theft is another concern. It's never a good idea to leave your car idling unattended. It's just too inviting to thieves.