Idle or turn the car off?


My husband and I are having a heated argument. If we’re in the car together and I need to run in to the grocery store for milk and bread, should I turn the car off or let it idle? My husband says let it idle “so that you don’t wear the starter out.” I say turn it off because of the price of gas. Who’s right?


Turn the car off, the amount wasted on gas will greatly outweigh any minuscule wear on the starter.


In addition to wasting gas, idling the engine unnecessarily causes the emission of more pollutants into the air, which is the reason why some municipalities have banned this practice. So–in addition to your husband’s favored action being wasteful, it is a detriment to health, and may be illegal where you live.

If you are sitting at a traffic light, common sense and good safety practice dictates that you keep the engine running. On the other hand, if you are in an unmoving traffic jam, waiting at a railroad crossing, or going into a store, the engine should be shut off.

Incidentally, it is also a good idea to go into banks and fast food joints rather than sit in an idling car at a drive-up window. Your wallet and your waistline will both be better-off by parking and walking.


Very few starters wear out. Some stop working, but most those are not because of wear. In other words, it is cheaper to turn the engine off.

That said there are a few other issues to consider.

If you leave an unattended car with the engine running, you are asking for a stolen car.

If someone is remaining in the car, they might appreciate the heat or A/C.

Sometimes it is wise to know you are right, but not to do anything about it and let someone else THINK they are right. This last one may well be the most important of the lot.


If you had gotten through to Tom & Ray they would have told you to give your husband a dope slap. Then comes the guffaw followed by a comment about “What a bozo!”

Anyway, the polite answer is to shut off the engine.

Print this page and leave it in the den covering the TV remote.



Did you know that it is illegal in Massachusetts to idle your vehicle for
more than 5 minutes (except for certain conditions, which does not
include warming your car up in winter)?

Mass. General Law, ch. 90, section 16A:

I see that the city of Toronto (Canada) and that London (UK) have also implemented city by-laws against idling of engines, as they’re mentioned as case studies at the Idle-Free Zone toolkit site from the OEE (Canada):

Ottawa and Montreal in Canada also have an anti-idling law:
I’m certain that there are other towns/cities/counties/states that have similar anti-idling laws… (I’ve seen mention of NYC, as the EPA has ticketed delivery vehicles there.)

More information about idling vehicles (why it’s better to drive it than
idle it, how long of a warmup your vehicle really needs, etc.) can be
found here:


Regarding whether to let your car idle or not; who cares, it’s really not very important.

Regarding having a “heated argument” with your spouse over something so silly; not a good idea, life’s too short. If one partner feels strongly about something like this, let them do what they want. Save the “heated arguments” for the non-trival stuff.


Well, turn the car off. If you have your own source of income, tell your husband you will pay for a new started if it ever does fail. You’ll get the money from saving on gas over the 150,000 miles it will take for it to go bad.

When gas was cheaper and I lived way up north, you left your car running in winter to avoid bad things happening to your car. But in any kind of larger populated area, leaving a car idling is a great way to ensure you will file an insurance claim for a stolen car. Then you get to explain why the insurance company should pay out on the claim when you left the keys in it and the car running.


Thanks for all of your help! Actually, we’re not really having a “heated argument,” we just want bragging rights. Thanks also for the info about idle cars being illegal in some states! Don’t know what the law is where we are (Wyoming), but it’s nice to know in case we travel somewhere.


Seriously, it’s not a very big deal either way. It will take forever to wear out the starter, and letting it run will use a few extra pennies of gas. Shutting it off is probably better overall, just do whatever you want and don’t worry about it.