# Why do some people let their vehicle motors idle? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [December 18, 2015, 12:21am UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743 "2015-12-18T00:21:54Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 25, 2015, 5:22pm UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/21 "2015-12-25T17:22:47Z")
Historically (like the 1960s) it was conventional wisdom that for big-rig diesel trucks it was more cost effective to idle for an hour or so than to shut down and restart. Much like with conventional fluoescent light tubes, much of the wear occurs during start-up and warm-up. Burning a couple quarts of cheap fuel to avoid that wear and tear was sound business. Nowadays that’s a lot less true, but the way most folks learn to do most grown-up stuff is by osmosis and handed down conventional “wisdom” which usually isn’t very wise. Or at least isn’t very wise any more. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 25, 2015, 5:40pm UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/22 "2015-12-25T17:40:50Z")
> [@Scumpup](#): > > Yes, I have one of those and enjoy riding it very much. I’ve posted enough about it here that it is something less than a secret. Your previous post was still remarkably stupid. Attempts to link possession of vehicles or guns to penis size are tediously so. I generally think that the only people who are truly concerned about it are the people who are always talking about the sizes of other people’s junk. > [@LSLGuy](#): > > Historically (like the 1960s) it was conventional wisdom that for big-rig diesel trucks it was more cost effective to idle for an hour or so than to shut down and restart. Much like with conventional fluoescent light tubes, much of the wear occurs during start-up and warm-up. Burning a couple quarts of cheap fuel to avoid that wear and tear was sound business. it’s not only that, most of them had no cold-start aids like glow plugs or intake grid heaters. If the engine got cold, you stood a good chance of not being able to restart it before running the batteries flat. and God help you if your truck had an air starter. Most/all modern diesels have at least glow plugs, and with the multi-shot 30,000 psi fuel injection they start easily. I drove a 2011 F-350 with the 6.7 Powerstroke diesel over a winter weekend a few years ago, and one morning it was like -8F. Got in, turned the key, and after three seconds of glow plug pre-heat the engine fired right up. here’s what cold starting a diesel _used_ to be like (this one even has glow plugs): This is what it's like now [![](https://img.youtube.com/vi/hmv0e8QDyDo/maxresdefault.jpg "-19 degree 6.7 Powerstroke cold start.") ](https://www.youtube.com/watch?v=hmv0e8QDyDo) ---
**Author:** ![IaMoDiNaRy](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@IaMoDiNaRy](https://boards.straightdope.com/u/IaMoDiNaRy)\ **Post date:** [December 25, 2015, 6:15pm UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/23 "2015-12-25T18:15:14Z")
> [@jz78817](#): > > by “loud,” do you mean they’re diesels? if so, he’s doubly stupid because diesels warm up extremely slowly. and _extremely_ slowly if just idling. In fact, some did tricks like my 2000 Ram with the Cummins turbodiesel did; if left to idle cold after about a minute it would go to high idle then switch to running on only 3 of the 6 cylinders in order to try to generate some heat. > > I just plugged in the goddamn engine block heater. Yep, they’re diesels… The big dummy. He’ll start them up and immediately get out to go do something incredibly important like suck down several cigarettes or sit on the porch staring out in space. :smack: ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [December 25, 2015, 8:23pm UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/24 "2015-12-25T20:23:04Z")
> [@Nefario](#): > > Yep. > > Because 95% of Big Tuff Truck Drivers need to prove how cool it is to hear their Big Tuff Truck rattle away and there’s huge peer pressure among Big Tuff Truck Drivers not to buck that tradition and suffer major penal shrinkage. Who knows when it’ll suddenly drop 50+ degrees and their Big Tuff Engine won’t start. :rolleyes: > > And some do work in cold weather. That is why I drive a small car and own a small gun. I’m compensating for my enormous penis. I’m with **scumpup** that was a dumb post. ---
**Author:** ![HeXen](https://avatars.discourse-cdn.com/v4/letter/h/c89c15/32.png) [@HeXen](https://boards.straightdope.com/u/HeXen)\ **Post date:** [December 25, 2015, 8:35pm UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/25 "2015-12-25T20:35:56Z")
Where I work, all of us do it. They are diesel’s, it’s hot or cold outside and plus we really don’t care enough to shut them off…ever. I let my car idle too because I listen to the stereo and don’t want to drain the battery. My bad habit is that I exit a vehicle and leave the door open. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [December 26, 2015, 5:03am UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/26 "2015-12-26T05:03:42Z")
> [@Scumpup](#): > > Yes, I have one of those and enjoy riding it very much. I’ve posted enough about it here that it is something less than a secret. Your previous post was still remarkably stupid. Attempts to link possession of vehicles or guns to penis size are tediously so. Oh I dunno. I was talking to a guy at work about whether to buy a new car, and I gave him one of my rationales, “As an American male, I only have 3 choices for hobbies: cars, guns and watching sports. I’m tending toward cars.” As a bonus, I would expect my penis to grow enormously. 😃 ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [December 27, 2015, 10:47am UTC](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743/27 "2015-12-27T10:47:15Z")
> [@Jackmannii](#): > > On the other hand, I see school buses idling frequently, including ones with no passengers stopped in the parking lot of a nature preserve a mile from my house (I’m guessing the drivers like to stop off for a smoke before picking up the kiddies). This apparently is [an environmental issue](http://www.environmentalhealthnews.org/ehs/news/idling-school-buses). Well, they probably just leave the engine on because it’s eerie sitting in silence if you are used to the low rumble and vibration. But I remember that it used to be that your air brakes failed if you weren’t careful about the door on a school bus with the engine off, and they might have had that drummed into them at a young age. [Previous page](https://boards.straightdope.com/t/why-do-some-people-let-their-vehicle-motors-idle/740743.md?page=1)