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Its bad for your car to let it idle in the morning?

Chew_12

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My teacher just sent this out. I wanted to see what you guys think.


It’s that time of year when mornings tend to get a little bit chillier every day. Because temperatures are on the low side, we’re supposed to let our cars warm up for quite a while before driving them off, right? Absolutely wrong!!! Just about the worst thing you could do to your vehicle’s engine—other than let it run low on fluids—is to let it sit and idle for more than a minute or so! I know, I know: Your dad did it, the salesman at the car dealership does it, your buddy who supposedly knows all about car motors does it. Ever stop and wonder why your dad had the family car in the shop so often, or why he traded in his cars every couple of years? Ever stop and wonder why the low-mileage car you drive off the lot already sounds like it has a cement mixer under the hood? Ever stop and wonder why your friend who knows so much about cars spends so much time fixing them in the first place? Unfortunately, our schools don’t teach young drivers about the very destructive practice of idling an internal combustion automobile engine, so young people wind up getting the wrong message from misinformed parents or friends or whomever. Repeat: It’s a very bad idea to turn on your car and let it sit idling for more than a minute—period! It’s not only bad for a car’s engine; it’s doubly bad for the environment! Amazingly, lots of people still perform this warm-up ritual every day—cold weather or not, much to the detriment of their cars and to the air we all must breathe.

I wasn’t always anthropologist from Flagstaff, Arizona. I used to live and work in the Cleveland, Ohio, area, where I had a very rewarding career as an engineer. For three decades I designed and manufactured parts for cars, trucks, snowmobiles, trains and tanks. During that time, I had regular contact and conversation with engineers from the major U. S. auto manufacturers. To a person, every one of them confirmed what I said to you above. Also, a close friend of mine worked for a firm called Lubrizol, a company that bench-tested engines using various lubricants to see how long car motors could idle before falling apart. (And he saw many motors “self-destruct” from prolonged idling!) In any case, as someone who was raised around automobiles, was a mechanical engineer for over 30 years before becoming an anthropologist and educator, has another close friend who’s been an ace mechanic for over forty years, and as a scholar and a scientist who has thoroughly researched this topic, I can safely make the statement:

Generally speaking, under all but extreme circumstances (say, minus 30° F), letting your car idle (“warm up”) for more than 60 seconds before driving can be very harmful to the car, and it’s definitely very harmful to the rest of us!

I remember an article from Motor Trend magazine some thirty-five years ago in which the author gave this basic rule: Once you start your car, drive it off as soon as the lights on your instrument panel go out. Once your oil light goes off, your engine’s oil is up to pressure and it’s time to put that engine under a load. I’ve followed that rule ever since, and rarely have my cars been in the shop for engine work other than routine maintenance—unless they were cars that I bought already used and abused. At least two exceptions to the rule do exist. First, old cars that have been sitting around for long periods of time often need a few minutes of warm-up before they can be driven without constantly stalling out. Second (I learned this in Alaska, from their Division of Motor Vehicles), when temperatures drop to minus 30 or below, it’s better for the environment—less polluting—to let the car warm up for a few minutes before driving. (Plus, from experience I can tell you that in those low temperatures your breath freezes to the inside of a cold windshield, making it difficult to see where you’re going!) Most of us don’t drive ‘50s or ‘60s cars, though, and the temperature here rarely—if ever—gets below minus 30, so neither of these exceptions apply to any of us in Flagstaff on a regular basis.

As I tell all of my students about everything, though, you needn’t take my word for it. Check out this topic for yourselves. Do the research! For you guys who spend so much time on the Internet, here are just a few of the many applicable Web references on the subject, which I’ve copied and referenced for you. (I’ve included opinions from a variety of sources. I’ve also italicized and bolded select phrases for emphasis.)

“Ten Things That Kill Your Car,” No. 8. Improper warm-up. Thirty years ago, the average…family had to consider switching on their television set four or five minutes before their favourite show was to air to allow proper warm up time for the TV set. Television sets no longer need the same consideration and neither do cars. Many people let their car idle for five or ten minutes before use to prevent improper wear. The ideology is correct, but the practice is flawed. Indeed, damage occurs in the first few moments that an engine is running. This is why it is extremely important to start the car and get moving immediately. With modern cars, the faster you can get the engine up to its proper operating temperature, the better. The way to get that temperature up quickly is to drive the car. Therein lies the tricky part, though. Until the car is up to that ideal temperature, it is important to drive with extreme care. That means gentle acceleration, restrained steering manoeuvres, and careful braking. Let the car shift nice and early. If you have a car equipped with a manual transmission, it is a good idea to allow five to ten seconds of warm-up with the car in neutral, just to ensure that proper lubrication gets into the gears. With the exception of this, I say start her up and get going—but with care.
http://www.news24.co.za/News24/Wheels24/SuperQuick/0,3999,2-15-1246_1115007,00.html

Q: I have a question about the warming up of cars in general. I have a 96 Pontiac Grand AM and I usually warm it up about ten minutes before driving it. A couple of guys on the job always tell me that letting a car sit idle is one of the worst things you can do to a car. They also tell me that with the cars now you can just get it in and drive. Is there any truth to anything that these guys are telling me? If not how long should I warm up my car? Thanks, Jason.
A: Hello Jason,
Those guys on the job are right; you better buy them coffee. A modern car, when cold, starts in what is called “open loop.” The computer is using set commands for fuel delivery, therefore the engine is running a tad rich, this means with an excess of fuel to ensure that it keeps running. Some of this fuel makes its way into the crankcase and along with other byproducts of combustion creates a witches’ brew which is not very good for the polished surfaces in the engine. To prevent this, the engine has to driven under load to heat the engine to normal operating temperature as quickly as possible to make it go into the “closed loop” where the fuel is controlled by actual engine requirements. An idling engine takes a long time to warm up and just wastes fuel and pollutes our environment and a pox upon those who use remote engine starters to cool their vehicles during the summer.
http://www.theglobeandmail.com/globemegawheels/ericarchive/011702.html

Q: Which is better for the vehicle when it is frigid outside? To warm up the vehicle first, or to start it and just drive off?
Fred: You can just drive off, as long as you do it gently. With today’s computerized, fuel injected automobiles it is no longer necessary to warm the vehicle up for any length of time. Start up the car, let the engine stabilize for about 30 seconds so that the oil can circulate, and drive off normally. Avoid hard acceleration until the vehicle has reached operating temperature, about 5 to 8 minutes. In real cold below zero weather, you would want to use a light grade (5w-30) oil so that circulation would be easier.
http://www.familycar.com/fredfaq.htm

Yarmouth (Nova Scotia) Insurance Services Limited: TIP #40 WARMING UP YOUR CAR
When you crawl out of bed on a cold winter’s day, it probably takes you a little while to warm up. Your car, too, needs some time to warm up so it can be driven safely. …You don’t have to let the engine run on and on before driving away. About a minute is all that’s needed to sufficiently warm up the engine. (Note that this tip is for harsh Nova Scotia winter conditions. –S.A.)
http://www.yins.ns.ca/tips/tip40a.htm

Many moons ago...Back in the days of the carburetor, there was a law that people lived by. And it said...You must thoroughly warm up your engine before driving the car. This law was deeply rooted in poor vaporization of the gas in a cold carburetor and intake manifold. It was accepted then that it was best to warm up the so as to eliminate hesitation, stall, or throttle tip-in sag. While this scenario may have served the driver well, it was the worst possible scenario for the engine. A cold engine experiences excessive wear due to the rich mixture required by the EFI system. This tends to wash fuel from the cylinder walls and aggravates wear between the rings and cylinder bores. …One should limit the amount of cold running time and accelerate the warming process. This can be done by driving the car at light load as soon as the oil pressure comes up to level. An engine that is driven immediately will have much higher coolant and oil temperatures than one that idles for 5 minutes. At the same time you will also warm up the rest of the drivetrain like the transmission and wheel bearings. Something idling cannot do.
http://www.automotiveforums.com/vbulletin/t1446.html

Q: I have a question about whether or not you should warm up your vehicle in the wintertime by just letting it sit there idle, or is it best just to go ahead once you start up your vehicle is just to start driving? (Again, the following tip is for cold-weather conditions. –S.A.)
A: We went to car expert Pat Goss for the answer. Pat says the most efficient way to warm your car (in the winter) is to let it idle for one minute.
http://www.nbc4.com/answerstoaskliz2000/1166079/detail.html

What’s the proper procedure for starting and warming up my car in the morning?
Fuel injected cars (1986 or so and newer): …Do not pump the throttle, do not push on the throttle during cranking, just turn the key and start the engine. Allow it to idle for about 1 minute, then begin driving. On newer cars (86 and up), allowing them to idle for 5 minutes is bad for them. Driving easy for the first five minutes is the key, because the engine will warm up faster driving it than it will just sitting there idling.
http://www.salemboysauto.com/faqs/faq-40.htm

If you drive the vehicle moderately until it gets up to operating temperature then it will warm up just as well as sitting Idling—or maybe even better. The theory of warming up an engine is that the engine is designed to operate at a particular temperature, metal parts expand and change shape dramatically when they change temperature and the parts are designed so that they basically fit each other when they are at their operating temperature. Operating outside this temperature range when the parts don’t fit as well can be harder on the parts—so moderate load on the engine is OK. In fact the engine running above idle is actually better because the engine throws more oil around inside itself at RPM's above idle and hence lubricates itself better than at idle. Ideal warm up is probably between 1500 and 2000 RPM, the engine would see this in moderate driving conditions. Starting the engine and slamming the accelerator to the floor to get that tire squealing roaring start (just like in the movies) is definitely less than ideal for the engine. If the engine warms up faster then the emissions tend to be a lot less as the catalyst lights off sooner etc.; plus the sooner the engine is at it's operating temperature then it runs more efficiently and therefore produces less emissions etc. The moderate driving theory also has the additional benefit of warming up the transmission as well as the rest of the moving driveline components not just the engine. Common sense of course dictates that if the windows are all steamed up it is probably a tad hazardous to be playing in traffic anyway—so a little warm up to get the defrosters going may be a survival technique.
http://www.racerchicks.com/auto/q_and_a/wintertips.html

Q: Do I need to warm up my car before driving?
A: Absolutely. Regardless of what kind of vehicle you drive, it takes a while before important fluids like oil and transmission fluid reach their intended destinations. (Note: Under all but extreme circumstances, those “important” fluids reach their destinations” within a few seconds. If they didn’t, your engine would go. S.A.) One of the best ways to extend the serviceable life of your car is to wait for one full minute after you start your car before driving down the road. This is especially true during cold weather, but the principle applies no matter the weather or where you live.
http://www.womanmotorist.com/MAINTENANCE/maint2.shtml

You’ll find lots of Q & A’s like these on the Web, in auto magazines, and wherever knowledgeable people discuss cars. Note that even those who somewhat disagree with the rest of us still say that one minute is the longest that you should warm up your vehicle! Here are some more:

Q: My mechanic tells me that letting my car warm up for a few minutes before driving it is good for the engine. Is he right?
A: Find yourself another mechanic, one who knows better—or one who’ll be more honest with you. We often are at the mercy of our mechanics, many of whom are extremely knowledgeable and trustworthy. (Hooray for those good guys!) Some aren’t so knowledgeable, though, nor are they trustworthy. For example of the latter, a friend of mine who used to be the service manager for a major dealership in Arizona confessed to me earlier this year that he quit his job recently because the management continually insisted that he lie to customers in order to bring in more dollars for the service department! Hopefully this is a rare situation. The point is, to whom are your going to listen: Someone who has a personal (or company) agenda to advance, or someone who is open-minded and objective about the topic?

Q: My car simply will not run if I don’t let it warm up for at least ten minutes before driving, in any weather. What am I supposed to do?
A: If this is the car that you drive on a regular basis, get another car! Something—I don’t know what—is terribly wrong with that vehicle if you’ve got to warm it up for that long. By letting your car sit idling that long, you’re not doing it any good, and you’re certainly not doing the world a favor.

Q: I like to climb into a nice, toasty car in the wintertime. What else can I do but let the car warm up?
A: Easy: Get over it! Hey, we’d all like our cars to be warm and cozy when we drive off in the winter. Your car will warm up a lot faster once it’s under a load, though—that is, once you’re driving it. The few minutes (2 or 3 miles worth) of chilly temperatures that you’ll endure in your car before it warms up are a lot less costly than the damage you’ll do to the vehicle—and to the environment—by letting it sit idle, pumping noxious exhaust into the neighborhood or parking lot.

Q: I don’t believe that letting my car idle for ten minutes before driving it hurts a darn thing. Why should I change what I’m doing?
A: Believe what you like. This is a free country. But remember: Belief is a poor substitute for knowledge. Hey, we can’t know everything, so we have to believe in some things. That’s fine for Santa Claus, monsters under the bed, and love at first sight, but not for cars. In the case of cars, the facts are clear. You don’t have to believe; all you have to do is get an education. If you don’t care about your car, think about the air that your family, your pets, and your neighbors have to breathe. If you have any concern whatsoever about their health, you’ll change what you’re doing. If you don’t care about your car or other people, you might consider how much money you’re wasting in gasoline by letting your car idle. If none of this matters to you, nothing I or anyone else has to say is likely to make any difference in the way you behave.


That’s all I’m going to contribute to this cause, for now. I won’t even get into the details of how an idling vehicle negatively contributes to air pollution—and to a variety of serious illnesses. That’s an article in itself, and lots of other knowledgeable people have written about it. Terms like smog, acid precipitation, respiratory illness, learning impairment, carbon monoxide poisoning, diseases of civilization, etc., etc., will pretty much sum up that topic.

I share the above information with you because, as an educator, ignorance and misinformation are my worst enemies. When we’re ignorant about a topic, we’re also easily misinformed about it. I’m also sharing this information because you’re my students. If your cars are content, chances are you’ll be a bit more content, too. Another and extremely important reason why I’m sharing this information is the fact that prolonged car idling wastes precious and finite resources. Why waste fuel—and the money it take to buy it??? The most important reason of all, though, is the fact that warming up your car threatens the health of each and every one of us. Toxic exhaust fumes aren’t mildly toxic; they’re lethal.
 



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TheFox88

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Thanks for sharing. I will not start up my truck 10 minutes before i leave in the morning now. Which professor sent that out?
 






96limitedX

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BS IMO...if that was true my f-250 should be dead right now. it has more idle time then miles on it.(has a hour meter installed on it) and heck so would everyone else car in town. everything i have heard from many different places say its MUCH better on a motor/tranny..heck the whole car. to start and let it get up to temp before driving it.
 






Chew_12

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TheFox88 said:
Thanks for sharing. I will not start up my truck 10 minutes before i leave in the morning now. Which professor sent that out?

It is Mr. ********. Im also not too sure what he says is true.

Edit: I dont think its good to give his name out w/out his permission.
 






TheFox88

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Are there any other opinions on this subject?
 






95offroadx

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that cant be right at all, you should always let a car warn up before driving it, its just like when you get up in the morning, you dont get up and leave in 5 seconds, its just common scence
 






IAmTodd

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To me, I think the car should be up to temperature in order for it to function correctly. I always leave mine idle until the coolant is up to 50*. This makes sure everything is circulated and that the transmission is ready to go.

How many people that live in amazingly cold climates leave their cars idle 24/7. And big trucks that idle constantly?
 






96limitedX

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yeah up north from here it can get -60 and its not unheard of to leave a car/truck idle overnight. i have not heard about it as much latly becaseu of gas prices i would assume and its not as cold the last few winters(only -40).

but up on the north slope its pretty common to leave them(big rigs and pickups) running 24/7. but they are not gas motors so i dont know what differances that would make.
 






99SportX

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I don't agree with that. When my engine is really cold, I wait until the needle hits C before going anywhere. If I just start driving, everything feels like crap. Steering, transmission, even engine. I haven't noticed any problems either.

In the summer, I usually let the X idle for about 30 secs before going anywhere.

Diesel engines don't like to be cold, so you frequently see a truck just idling in a parking lot during winter with the driver nowhere in sight.
 






CaptainObvious

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I'm claiming BS. Look at Truck Stops. Those damn things run all night. I don't know if I'd let it run for 20 minutes, but I always let it warm up for a few minutes.
I also let the truck when on quick trips in the store.
 






spindlecone

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CaptainObvious said:
I'm claiming BS. Look at Truck Stops. Those damn things run all night. I don't know if I'd let it run for 20 minutes, but I always let it warm up for a few minutes.
I also let the truck when on quick trips in the store.
Diesels V/S gas engines, is like apples and oranges
 






Chew_12

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spindlecone said:
Deisels V/S gas engines, is like apples and oranges


I was just about to say that. This e-mail is about gas engines not Diesels.
 






chriswells78

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This @$$hole doesn't live in a climate like I do. Bad for my motor or not, if it is 20deg outside, I'm warming up my truck in the morning before I haul my happy ass to work. Besides, all fluids get thicker in the cold. That is a proven fact of physics. Therefore, your oil pump has to work harder to pump oil, PS pump has to work harder to pump PS fluid etc. How can this be good for a motor under the stresses of Stop and go driving to work? This sounds like another hippie-tree-hugger trying to save the world :rolleyes:
 






Turdle

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bs
The way I understand it, until the operting temp is reached, a newer engine is running in limp, open loop , rich mode, which means more pollution at load than when warmed.
I like warmed leather, and dislike anyone trying to take it from me
Gentlemen start your engines
 






unclemeat

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Where do people get this crap from? Warming you car up is actually good for it for sereral reasons. The oil flows better at operating temperature. The the best reason is that allow a gas engine to operate at normal temperature make all the volitale crap from the gasoline go out of the oil, improving lubrication.

If a engine was supposed to run at low temperature then the coolant system would make it happen. Oh yea I am an Engineer.
 






Chew_12

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chriswells78 said:
This @$$hole doesn't live in a climate like I do. Bad for my motor or not, if it is 20deg outside, I'm warming up my truck in the morning before I haul my happy ass to work. Besides, all fluids get thicker in the cold. That is a proven fact of physics. Therefore, your oil pump has to work harder to pump oil, PS pump has to work harder to pump PS fluid etc. How can this be good for a motor under the stresses of Stop and go driving to work? This sounds like another hippie-tree-hugger trying to save the world :rolleyes:

WTF...You dont even know him and you call im a #######? Come on!!!! :fire: :fire: And dont even say it doesnt get 20 deg here. It gets to about 5 deg at night here so STFU. I wanted your opinion, dont f-ing bash him.
 






spindlecone

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jtsmith said:
bs
The way I understand it, until the operting temp is reached, a newer engine is running in limp, open loop , rich mode, which means more pollution at load than when warmed.
I like warmed leather, and dislike anyone trying to take it from me
Gentlemen start your engines
Open loop with heated O2 sensors lasts about 10 Secs from cold startup.
Agreed we all would like to get into a warm car on cold mornings.
Our daddys taught us to always warm up the car, but that was in the days of carburators.
People are talking about oil flow, normally after a couple secs, you have full oil pressor to all the engine componants, do's warm oil have better lubricating propertys than cold oil?
This could be a great thread if somebody can post some mechanical reasons to warm up a modern day gas engine before putting it under normal load.
Am not a tree hugger, but if you have 50 million people (hypo number) warming up in the AM, thats alot of gas, maybe for no reason other to get into a cozy car,JMO
 






MONMIX

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I have heard this for years and this is the first time some one had presented WHY.

Open Loop, it a legtamate reason, but also in my opinion insignificant. I would imagine the amout of time it spends in closed wile ideling as opposed to get in and go is not a tremendous differance. But then again I could be wrong. This would be a good test for our own data king and test master Aldive. Now getting him out of sunny Florida might be a bit of a challange.

As far as " The worst thing you could possibly do ... " I think is being a good bit sensionalistic.

Either way, I hate cold. I hate my truck being cold.
Let it run.
 






MONMIX

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spindlecone said:
Open loop with heated O2 sensors lasts about 10 Secs from cold startup.
Is that a fact or are you speculating ?
 



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spindlecone

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MONMIX said:
Is that a fact or are you speculating ?
On 35 deg mornings, this past week, my scangauge reports open loop for about 5 secs, than it will report closed loop.
Heated sensors come up to full temp (600/650 degs) in no less than 10/15 secs in any cold clime
 






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