Comments on: Does idling a car or truck save gas?

By: Should I Wash My Dishes Before Putting Them In The Dishwasher? – Greg Laden's Blog

Wed, 13 May 2015 13:34:37 +0000

[…] of your use of technology. Do you let your car warm up for a long time on a cold winter morning? To you leave it running when not actually driving because you heard it takes more energy to start it…? Do you leave florescent lights on in the office all day even when the rooms are empty because you […]

By: shigzeo

shigzeo — Fri, 17 Apr 2015 07:57:04 +0000

@Makeinu: there may be cars that cut engines whilst stopped, but drivers do not. I’ve never seen so many cars idling in any weather. The air is very bad here at ground level because at a minimum, 20% of cars stopped are idling, usually for at least 10 minutes, often for hours.

Individuals have no understanding about air quality, but still will whinge about China polluting the air.

Biggest cognitive dissonance I’ve seen in a rich, educated country.

By: Delurked Lurker

Delurked Lurker — Sat, 06 Jul 2013 01:48:15 +0000

If you have a turbo diesel and its been on the road traveling for sometime it is best to leave it idle a few minutes before turning the engine off, It will reduce wear on the turbo unit. Likewise when starting a turbo diesel idle for a short time for the same reason.
I got this information from the manual to my turbo diesel,

By: Week 25: Sacred Idleness | Oregon Pilgrim

Week 25: Sacred Idleness | Oregon Pilgrim — Wed, 03 Jul 2013 21:45:46 +0000

[…] Does idling a car or truck save gas? (scienceblogs.com) […]

By: Greg Laden

Greg Laden — Tue, 02 Jul 2013 22:01:56 +0000

” but there is really not much reason for the average driver to leave a diesel idling other than the desire to act like a big-rig trucker. ” <-- exactly.

By: Mark P

Mark P — Tue, 02 Jul 2013 18:18:04 +0000

Diesel engines use very, very little fuel when idling, but there is really not much reason for the average driver to leave a diesel idling other than the desire to act like a big-rig trucker. And now even they are being encouraged to shut down when stopped. There are various approaches to providing cabin heat/cooling when parked long-term other than the main engine, and some truck stops apparently are providing air conditioning and other plug-in services to truckers. Diesel engines use so little fuel when idling that the engine won’t reach operating temperatures at idle(or takes a very long time) from a cold start, and can overcool so much that fuel condensation can wash oil off the cylinder walls and cause premature wear.

By: makeinu

makeinu — Thu, 27 Jun 2013 23:47:06 +0000

Japan has a big campaign called “Idling Stop”.

Even the city buses will kill their engines at stop lights, unless safety dictates otherwise (on some of the rather steep hills, for example).

By: Eric Lund

Eric Lund — Thu, 27 Jun 2013 17:26:31 +0000

On a really cold day, I can definitely see leaving the engine running just so the heater stays on.

I can’t speak for you specifically, but I, and most people I know, usually dress appropriately for the weather when driving somewhere. In most cases you have to venture outside the car at one or both ends of the trip, and during cold snaps moving about (i.e., getting out of the car) helps you stay warm. Not to mention the risk (small, I’m sure, but not zero) of carbon monoxide poisoning. I’m slightly more sympathetic to the air conditioning issue, but even then, unless there is a mobility issue, why are you staying in the car?

By: Calli Arcale

Calli Arcale — Thu, 27 Jun 2013 14:42:44 +0000

The engine may cool down slowly in the winter, but the *cabin* sure cools down quickly! On a really cold day, I can definitely see leaving the engine running just so the heater stays on. But this isn’t to save gas, of course, it’s to save the passenger who is waiting for Spouse to finish a shopping run or whatever. And in the summer, you might keep the car on for the A/C so any passengers left behind are comfy. So idling the engine is totally fair, as long as you’re not doing it in the delusion of saving gas. 😉

By: Eric Lund

Eric Lund — Thu, 27 Jun 2013 13:57:51 +0000

@Jesse: Starting the car is a separate issue from warming it up. In places where temperatures of -40 or lower are common, such as Fairbanks, cars have electric engine block heaters installed so that you can start it in cold weather. When I was in Fairbanks the recommendation was to “plug in” your car whenever the temperature was below +20 F (which was most of the time in winter months, as average January temperatures there are about -10 F). But once you got the car started, the engine would warm up reasonably quickly. I did observe some drivers in Fairbanks who idled while filling up their cars (which is a Really Bad Idea for obvious reasons), presumably because they feared not being able to restart the engine after they were done refueling. But that never made sense to me either (assuming your starter isn’t iffy), since it takes the engine quite a bit longer than that to cool down, even when it’s -40.

In temperatures that cold it is actually not unusual for engines to overheat. This happens because the belt that drives the coolant pump becomes brittle and falls off, and without coolant running through the engine block the engine temperature spikes upward. For this reason we generally travelled in convoys when going outside of the Fairbanks/College urban area*, and the rental car people at the Fairbanks airport are quite understanding–you just tell them where you had to abandon their car, and (as long as you weren’t on one of the roads the contract specifically forbids) they’ll close out that rental and give you another one.

*Peculiar Alaskan traffic law: you are required to stop and offer assistance to any motorists whose vehicle is disabled. The obvious reason is that situations that would be merely annoying elsewhere are potentially life-threatening in Alaska.