Get 30 More Miles Per Tank: Turn Off Engine If Idling More Than 10 Seconds

If you’re going to be idling for more than 10 seconds, you can get 30 more miles per tank, according to the Canadian Office of Energy Efficiency and the Celias blog.

Idling uses up a lot of gas. You’ll save money, and the environment. The Swiss like this method and it’s the law in several of their cities to turn off your car at stoplights.

But what about the gas used to start a car? All cars use fuel injection, so starting a warm engine is negligible. And the cost of that or the wear on your starter is far outweighed by the fuel savings. — BEN POPKEN

10-Second Rule [Celsias] (Thanks to c-side!)
(Photo: hanapbuhay)

Comments

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  1. tcabeen says:

    Unless you have a 10+ year-old car of the type that causes you to cheer when it actually starts in the morning. Then you don’t want to risk it at every red light. ;)

    Ah, but think of all the money you’d save if you traded that in for something more reliable!

  2. gorckat says:

    30 per gallon or per tank?

  3. OnceWasCool says:

    Just wondering. Wouldn’t that cause extra wear on starter and flywheel? Driving the speed limit will save a lot more gas, instead of 10 miles over like we do here in Georgia.

  4. gorckat says:

    When I tried it the first time, I was amazed to see that I had gotten nearly 30 more miles on that tank than usual.

    Answered it myself by reading :p

  5. pe_tor says:

    The original article claimed 30 more miles on a tank of gas on a car that apparently averages around 30 mpg (since the writer equated 30 miles with an extra gallon of gas).
    I would also recommend that one pay attention to light timing to make sure one can have the engine started slightly before the light turns back to green if one is at a stoplight. If you delay traffic and make lots of people miss the next light (assuming they’re timed well), then it’s quite counterproductive since the best thing for a car’s mileage is to not have to slow down.
    Also of note is that BMW is in the process of introducing a system that automatically stops the engine when it is not in use, much like most hybrids, but on regular cars (starting with the 1series and 7 series I believe). This will become a common feature in the next few years on many brands of cars.

  6. brilliantmoron says:

    That’s 30 more miles per tank, not per gallon. Headline is wrong. Had me all giddy for a second.

  7. That’s thirty more miles per TANK, not per gallon.

    Read the article carefully. I still might think about shutting off the engine in some situations, but I’m not going to do it at every red light just to save that small amount.

    If you have a fifteen gallon tank and get 25mpg, then you’ll get 27mpg this way. Up to you.

  8. bambino says:

    If someone tried to do this in front of me at a redlight, they’d have a much bigger problem than trying to save gas.

  9. shekondar says:

    “Unless you have a 10+ year-old car of the type that causes you to cheer when it actually starts in the morning. Then you don’t want to risk it at every red light. ;)”

    My car is only 6 years old and I cheer when it actually starts! (It’s a Ford. 86k miles and already on it’s second engine.)

    Personally I’d rather use a little more gas, and save the wear & tear on my car (and not piss off the jerk behind me at the red light). The only time I shut it off instead of idling is if I’m going to be stopped for a few minutes (for example at railroad crossings).

  10. My car is 20 yrs old and solid as a tank. It is not fuel injection. I let it idle in the winter while I shop as its normally butt ass cold. However, I think with new cars, this idea could work. But like shekondar says, I am not crazy about the wear and tear on my starter. Starters are a pain to replace.

  11. grkgus says:

    Destroy your engine to save 2 dollars. Great.

  12. Musician78 says:

    Starting your car is horrible for it. Sounds like it could be more costly in the long run.

  13. grouse says:

    If someone tried to do this in front of me at a redlight, they’d have a much bigger problem than trying to save gas.

    Would they really? What problem might that be?

  14. Y@permissionmag: I think you may be right on this one.

    As near as I can tell the source of the “Idling saves fuel” fact comes from Natural Resources Canada (Office of Energy and Efficiency?) Anywho they give no public stats online as to how much petrol turning off your car after 10 seconds actually saves, just that turning it off after 10 seconds is the point when at which it takes less fuel for your car to start up versus leaving your car running.

    So how much mpg would you save?

    It would be irresponsible to say. Why? Because when your car is idling you’re getting 0.0 miles per gallon. Since you’re not moving anywhere you’re just eating fuel while you’re idling and I think that’s the overall point that Natural Resources Canada is trying to make.

  15. Mike Panic says:

    Someone needs to get Myth Busters involved in this – I’m with most on here who say that more harm will come to the motor and all the accessories attached to it, such as the starter, from practicing these methods.

  16. TedOnion says:

    I am also going to have to agree this is not the best idea. Although yes, you will save gas, starting a car is not good for the engine. It is mildly rough on the starter, rough on the battery, hard on the transmission, and very rough on the engine due to the time it takes to build oil pressure critical to protecting the engine.

    I have always thought the best way to save gas is to keep the car well tuned by following your maintenance schedule, and changing driving habits. Driving habits being the big one here. . . stop hot-rodding!

  17. Slusy says:

    Couldn’t you just throw the car into neutral and achieve most of the same effect without starting your car at every red light?

  18. TheDude06 says:

    My car already does this! (toyota prius) its one of the many things it does to maintain fuel efficiency. In my case, the engine doesn’t actually spin again until about 8mph, and the electric motor covers any delay there would be in responsiveness.

    Of course theres one situation that this doesn’t account for… winter! even the prius refuses to shut off the engine at a light if I have the heat switched on. I guess if you are sweedish, you just have to pack an extra scarf when driving?


    Other neat prius fact: it stores 3L of “coolant” in a thermos style container in the engine. a minute after the car is powered off, it pumps the warm fluid into the container. On start, it re-injects it to pre-warm the engine. this gives the fuel benefits of a warm-start, even the next day! every little bit helps

  19. Red_Eye says:

    @Musician78: Absolutely correct! The one of the most damaging things you can do to your engine is start it cold. Starting it warm with no oil pressure isn’t much better. You cause additional wear on your starter flywheel gear teeth, battery, alternator, and en engine internals not to mention if you did this in stop and go traffic you could potentially overheat your car and yourself in the summer.

    This is one tip thats definitely NOT worth it.

  20. BMR says:

    instead of spending time and wasting effort on affixing band-aids to the problem, why not focus on the truth:
    the GAS engine is outmoded. When we start to try and piece together measly savings by turning the car off at stop lights, don’t you think we have hit a wall?

  21. fastm3driver says:

    Starting your car from cold is damaging, but if it is already warm it isn’t and it will also start easier. Just wait until it’s warm.

  22. fawgcutter says:

    Arrgh, it’s just a Canadian-backed study to substantiate a no-idle ordinance one Toronto community enacted.

    I remember reading about this last summer while working in Ontario

  23. pe_tor says:

    Another thing to consider, it might be illegal, depending on where you are, to turn off your car in the middle of traffic.
    If your car is new, works well, and is warmed up, this probably isn’t very bad for your car. I’d say if it seems to start instantaneously once warmed up, it’s fairly safe to do this. If you car springs back to life a little slower, that might be a little more unpleasantness than your engine needs too deal with.
    If I weren’t so lazy, I’d ask my old man, he’s been a powertrain engineer for 30-some years. He’s driven cars that do the engine shut off automatically when the brakes is applied and the car is stopped, and they have some other things in them tweaked to make starting so fast that he couldn’t get his foot off the brake and on the gas before the engine restarted.

  24. usa1 says:

    “The Swiss like this method and it’s the law in several of their cities to turn off your car at stoplights.”

    It’s amazing that people are OK with a LAW that says you have to do this. Move along sheeple.

  25. m. mangosteen says:

    Saving a couple of gallons per tank may not be the most exciting thing, but I like the idea at long lights to just prevent my car from spewing all that crap in the air. A couple of lights near me take forever – I think I’m going to try it (and hope I’m not in front of bambino!

  26. notallcompaniesarebad says:

    This is at least the second thing I’ve seen referenced here (the other being changing your boarding pass) that I think it incredibly misdirected.

  27. Odwalla says:

    I tried this last fall for about two days. It ended badly, with me not being able to start my car at a busy intersection, in the left turn lane, during rush hour, in the cold rain, in northern Virginia. I was wet, frustrated, embarrassed, and had a lot of angry drivers behind me.

    As it turns out my four year old car had just about run through its original battery. The time between stop lights wasn’t enough for the alternator to put any charge into the battery. I drained it and then couldn’t start the car again. Luckily for me there was a car dealership at the corner that loaned me one of those portable quick-jump-start battery units. I still ended up blocking traffic for about a half an hour.

    I wouldn’t recommend this to anyone. Is the wear on your battery, starter, flywheel and other components, and the risk of being stranded really worth an extra 1-2 gallons of gas saved for every 250-300 miles driven?

  28. Hoss says:

    Would Donna in the red camaro please ask Car Talk for us? (Can anyone imagine doing this repeatedly in a city like Boston or NY? I think the courts would rule justifiable road rage for whatever the result might be)

  29. TechnoDestructo says:

    @shekondar:

    It’s a Ford what?

  30. Trai_Dep says:

    This seems silly.

    Although, I wish there were more drive-thru lanes that were on a downward slope. There were a couple in the Bay Area, that presumably, some virtuous person planned. Sweet sweet goodness, being able to coast your way through the line, engine off, until you could grab your vittles and run. No breathing fumes, either.

  31. notallcompaniesarebad says:

    Trai_dep: that is the coolest thing I’ve seen in this thread. That’s a great idea.

  32. Scazza says:

    @tcabeen: Thats the first thing I thought when I read this. My family celebrates when the car starts in the morning… there is NO WAY IN HELL I would ever do this at a red light…

  33. ozwaldo says:

    Coasting… reminds me of this article of a guy taking it way too far……

    http://www.motherjones.com/news/feature/2007/01/king_of_th

  34. SpyMaster says:

    30 more miles per gallon, he says? No way. He must be smoking too much of whatever is coming out of that tailpipe in your photo.

  35. LatherRinseRepeat says:

    Wow. Every “gas saving” tip I’ve read lately has been incredibly stupid. As everyone else has indicated, all the wear and tear you incur just isn’t worth the extra 1 or 2 gallons you’re going to supposedly save. If you want to save gas, drive less.

  36. @trai_dep: wow what a great idea! I do agree, I like the coasting thing.

  37. formergr says:

    @pe_tor: It is definitely *not* illegal anywhere to turn your motor off while at a stoplight. Not starting it back up again and sitting there? That could conceivably result in a fine, but even that’s unlikely.

    The Germans do this in many places and even have countdown timers on many longer stoplights so that you know when you should turn your car off (along with a sign reminding you to do so). Germans are fricking obsessed with taking good care of their cars (even the non-high end ones, they don’t all drive Mercedes or Beamers), so I find it highly unlikely that turning your engine off at a light and then re-starting it (assuming it’s warm) is damaging. If it was, they really really wouldn’t do it…

    Seriously, don’t get between a German and his car– right now there is some hardcore backlash against some lawmakers there who suggested putting a speedlimit on the autobahn to be more environmentally responsible.

  38. evilferretvictim says:

    Hmmm….interesting. I’ve always been told that unless you were going to be in idle for a long period of time (over 10min)..It’s best just to keep your car running. I was under the impression that starting your car eats up more gas than idling for a few minutes…

    Now obviously I don’t know jack about cars…After looking over the comments here it looks like shutting down your car does save gas, it just isn’t good for it?

  39. KivaWolf says:

    Just a thought, wouldn’t doing this often, even if your car has fuel injector, starting up the car would wear out the starter sooner. I mean yes we start up our car every single day but imagine if your starter fails right when the light turns green.

  40. formergr says:

    I think as another commenter mentioned this topic is good fodder for the Mythbusters. So many “tips” or common practices for cars harken back to the days before you had fuel-injected engines and other modernizations. Could it wear out your starter faster? Possible, but we don’t know. Just saying it’s “bad for the engine” is a non-starter (ha!)– no one has the research to back it up.

  41. bambino says:

    @grouse: Multiple expletives flying from multiple drivers having to pull into oncoming traffic trying to get around their retarded ass because they wanted to save a few pennies. Maybe even a flying smoothie.

  42. aka Cat says:

    My vehicle is not fuel injected, so I won’t be doing this. Then again, it gets 63/mpg.

  43. Die Schwarze Ewigkeit says:

    Right. Let’s do some math here.

    Let’s assume you own your car over 100,000mi.
    Let’s also assume you get 20mpg.

    100000mi/20mpg = 5000gal of gas over the life of the car.

    Now, let’s assume a 15gal gas tank. Seems average.

    5000gal/15gal.per.tank = 333.33tanks.

    At 20mpg, your 30mi extra of is 1.5gal/fillup.
    Let’s also assume gas is $2.75/gal.

    333.33tanks * 1.5gal/tank = 500gal.
    500gal*2.75/gal = $1375.

    So, you theoretically save $1375 doing this. That’s a pretty big chunk of change, but it assumes that this will do no additional damage to your engine. Knowning what I know about engines and oiling systems, unless you install a preoiler, you’re going to do more damage to the valvetrain and the bearings doing this. How much is really dependant on too many things to call safely, but I think we can assume that a large percentage of engines might have to be rebuilt or replaced doing this when they maybe wouldn’t have had to be. Also, you’ll definitely go through at least twice as many starters and batteries this way and those are neither cheap nor easy to replace in many cases. Thus, I call it a gamble. I’ll leave it up to you, but I for one am leaving my engine running.

  44. shiftless says:

    Sounds like too much stress and strain on the car to be worth it in the end.

  45. Dacker says:

    I’ll never forget what I saw while on a business trip to Barcellona.

    When a cab picked-up a passenger in the taxi line at my hotel (Ritz-Carlton), the drivers did not start their engines and pull-forward a spot; they simply PUSHED their cars ahead!

    I cannot imagine any US cabbie doing that….

  46. NaturalDesignChick says:

    Jamie & Adam? Are you listening? This would be a good one.

    I do turn off my gas-guzzler when I stop but only when I’m waiting for a train. They average 5-10 minutes here. I’ve considered knocking on windows to tell others about this idea but figured I might get “a flying smoothie” as bambino mentioned.

  47. Musician78 says:

    @grouse:

    Probably a severe beating. Some hospital bills, perhaps a smashed out window. Maybe worse. It happens. And you never know, he could be the dude that commits acts like that.

    Although sometimes I feel that road rage should be allowed in extreme cases. Like when some asshole doesn’t want to do the speed limit, and doesn’t want to pull over for the line of cars behind him that wants to do the speed limit.

    Or people who do not merge as they pull onto the highway. They just get on and don’t even look.

    Or people who tailgate the crap out of you when you can’t help going to slow because the asshole in front of you is preventing any increase in your speed. You are therefore forced to tailgate him in hopes of him pulling over.

    Actually, come to think of it, I can think of lots of reasons to legalize road rage…

  48. Xkeeper says:

    Stopping your car at stop lights, at least with standard cars seems to be a really stupid idea (from comments)

    However, if you’re like me, stopping it while you’re stuck in a drive-through for 5 minutes is a good idea.


    Although I must say, the idea of adding countdowns to traffic lights would be a very wise decision. It makes the red-light runners a little less common (since there’s no “guess” to if you can make it or not) and such, and you can tell if you’re going to hit a red light earlier.

  49. silenuswise says:

    Sounds like a good idea, but it’s apparent from the number of people still without fuel-injection cars that idea is better in theory than practice. Actually, it sounds sort of gimmicky (and this coming from someone who used to try to reduce brakewear by slowly drifting his 1985 Buick LeSabre before every stoplight), and I think what will happen first is improved technology that provides some sort of automatic shut-off when idling–similar to what pe_tor said above. The clear advantage here is that drivers wouldn’t have to think about it, like a refrigerator light going off when you shut the door (silly analogy, I know).

  50. Joe Hass says:

    The number I have always heard for the break-point of letting an engine run versus shut-off/restart is 60 seconds, so 10 is a new one for me. As someone noted, there’s no research on the link, which causes me pause.

    The two “tricks” I use when driving to increase gas mileage:

    1) When in stop-and-go traffic on a limited-access roadway (like a freeway), be extra-conservative in using the gas pedal. Just because the two cars ahead of you have sped away doesn’t mean you should, too: you’ll all be hitting the brakes in a moment, wasting all the momentum your gas uses. The key is to try to allow the traffic to get to a constant speed to avoid ‘jackrabbit’ starts (as an added bonus, you’ll help clear up the traffic jam!) There’s no shame in having six car lengths of space ahead of you just because the other cars decided it’d be critical to get to a fast speed quickly, only to hit the brakes hard because traffic stops again.

    2) When on a standard street with traffic signals, pay close attention to any signal within 1/2 mile from your current position. In particular, watch the pedestrian signals: they’ll flip to flashing don’t walk well before the signal goes yellow. If it becomes clear you won’t clear a signal, release the gas pedal and coast to the light. If you’re really obsessed with it (I am), put the car in neutral, which disengages the gear and allows the RPM to drop to idle. There is nothing more wasteful than ‘driving’ to an obvious red light.

    As an aside to BMR: yes, the gas-based engine is so 20th-century. However, a bigger problem lies in the fact that one thing drivers simply don’t know how to do is drive to save gas. Whether it’s accelerating to stopped traffic, or punching it off the line, or the 15-minute warm-up in the morning: drivers just aren’t aware of how much fuel we could save simply by doing the little things or unlearning things that aren’t true anymore.

  51. velocipenguin says:

    Something nobody has really pointed out yet is that starting one’s car is by no means an energy-neutral thing to do. Starter motors draw a tremendous amount of current from the battery, on the order of hundreds of amperes; once the engine is running, the power used to start the car has to be replaced by the alternator. Putting such a heavy charging load on the alternator results in (surprise, surprise) more fuel consumption. Many cars also feed extra fuel to the engine during starting, which would further negate any gains from using this method.

    Wear and tear concerns are also a major problem. Cycling the battery between charged and discharged states 30 times a day will cause it to fail sooner than it otherwise would. Also, low oil pressure during starting is very, very bad for engine bearings, turbocharger bearings, and valve guides. None of these things are fun or inexpensive to replace. If you really need to save fuel that badly, work on your driving habits instead of abusing your car.

  52. zolielo says:

    Not for me as well by the same rationale as stated by many others. Swapping out starters is such a pain…

  53. Anonymous says:

    @bambino & @Musician78:

    Wow, a couple of e-thugs on Consumerist. Nice. You two just brought the level of this site down a few notches all by yourselves.

    Congrats.

  54. traezer says:

    I did this while driving through the border from Canada to the US. I was sitting in stop and go traffic for a half hour or longer, so it seemed like a good idea to just turn off the car when I was stopped for five minutes at a time. By the time I was stopped by the border patrol to have the car searched, it would not start back up. Nothing like having angry angry border patrol people push your car through the border and tell you they are not going to help you at all.

  55. ikes says:

    @Joe Hass:
    those are actually good ideas. the first would work, in theory, but here in san diego if you leave just 1 car length between you and the car in front of you, you WILL get cut off. gotta fill that space!

  56. bambino says:

    @s0crates82: I never knew I had so much power! But seriously, let the first motorist who hasn’t flipped the bird cast the first stone.

  57. Chese says:

    Certainly I can see the wisdom to turning the car off if you will be idling for extended periods of time but the suggestion of turning off your car at red lights is insane.

    1) You need an engine running for heat/AC and for power steering and brakes. I have been at red lights with emergency vehicles coming up from behind me requiring me to move over with the pack to make room.

    2) If you want your radio/lights etc on you will put a drain on your battery.

    3) Alternators/starters do wear out and are not cheap. I work on jet aircraft w/ electric starters and they have a limit for starts in a specific time period for a reason, of course those starters cost a fair bit more :P

    Honestly, if you really want to save gas, drive slower. Its that easy.

  58. Musician78 says:

    No kidding. What I love is how serious people take some of the comments. My comment was obviously a joke. I don’t understand how the joke was missed. I guess I need to keep in mind that some people are devoid a sense of humor. *Sigh*

  59. mcgyver says:

    I have traveled through Asia several times for work in cities where the traffic is ferocious and the gasoline/diesel fuel is 3 times the cost it is here.

    Probably half the private motorists and 100% of the taxi cabs shut the engine off at stop lights.

    Once I found a cabbie who spoke some English and I asked him about this practice. He said his cab (Toyota Corolla) had the kilometer equivalent of 300,000 miles with the original engine and starter motor. Apparently there is no tangible or negative effect to doing this.

    These days I work in tech service in support of commercial fleets. The ‘damage’ folks are talking about WRT starting an engine ONLY applies to a bone-cold engine when all the oil has gone back to the crankcase. On a warm engine with a modern anti-drainback oiling system the engine will remain fully lubricated for an hour or so after shutdown.

    Now I own a 1 month old Camry Hybrid and guess what? It does all this stuff automatically.

    I think the Canadians are on to something here. Give it a try!

  60. swalve says:

    musician: The joke wasn’t obvious.

    technodestructo: I bet it’s one of those Fords that don’t require maintenance like oil changes. I just sold my 1999 Contour with 123000 miles on it for $2500- the engine was still clean on the inside and ran like new.

  61. Musician78 says:

    Well, if I am going to start beating the crap out of other drivers, I certainly wouldn’t be writing about it in a public forum. The whole post was spiked with sarcasm. Damn. *It must be certain parts of the country….*

  62. bdgbill says:

    Before deciding to turn off your engine at a red light to save gas you should weigh the risk of being dragged out of your car and beaten to a pulp in the middle of the street by the guy behind you (Me).

  63. Musician78 says:

    Dude…. you are bringing down the level of this site. *The shame!!*

  64. grouse says:

    @bambino: But seriously, let the first motorist who hasn’t flipped the bird cast the first stone.

    I can say with some certainty that I have never flipped off another motorist while driving.

  65. Musician78 says:

    Did you have your middle fingers cut off in a freak combine accident?

  66. grouse says:

    Nope, just not the sort of thing I do. Although, even if I did, it’s not nearly the same thing as threatening to throw a missile at another driver.

  67. bambino says:

    *applauds Grouse* Congratulations! Would you like your nun’s habit now or later, Sister?

  68. woosht says:

    I prefer the numbers myself:

    100,000 miles/20 MPG/15 Gallon Tank (numbers from an earlier poster) means I saved $1375 over the lifetime of the car.

    Let’s take it just one step further, and assume that 1% of the time my car does not start as planned, resulting in lost time (plus other possible but unidentifiable consequences). Let’s also assume the median time for my car not starting is 10 minutes — (perhaps I will learn to carry a instant-jump-start unit in the trunk!)

    On my commute, I stop at approximately 10 lights. This means that 1/10 days, or once every other week, my energy-saving habit will result in either loss of my or other people’s time. Since my rate is in the neighborhood of $40/hr, that’s $6.66 every time my car doesn’t start… we can leave out the passengers for now.

    So 25 times a year I will lose $6.66 = $166.66/yr

    Lets now assume I’m driving 15,000 miles a year, so I’ll be reaching the 100k mark in 6.66 years.

    $166.66 * 6.66 = $1110 in lost time

    Now if only one starter fails I’m in the red. Meanwhile I have to suffer other problems associated with car trouble and related stress. Ouch.

    Bear in mind that that accelerator pedal — it’s connected to the throttle which directly controls how much gas is going into the motor. Just keep your foot out of it!