Leave car running?

[aaronc879]

There was a local news report warning people not to leave your car running unattended. Apparently a lot of people leave their cars running unattended to keep it warm this time of year. Locally it's against the law to do so because it a risk of auto theft(duh). Does anyone leave their car unattended and running when they go into the gas station or post office etc? I'd never even consider leaving it running. In fact, I lock the doors anytime it's out of my sight even if just for seconds.

 

[Khan]

A lot of folks do. Years ago on a cold morning I walked over to the local Dairy Mart for a cup of coffee and there were 7 vehicles running in the parking lot.

If folks actually read the owner's manual, it says not to leave the car running (warming up) for more than a minute or so before driving off.

Warming up the car is some sort of modern folklore.

 

[Goonie]

With remote starters installed on our cars. we fire 'em up and let them run for a while before we go out on cold days (and nights), so the interior is warm when we get in...and so the windshield is defrosted/de-iced. I don't worry about anyone stealing them, since you still need a key inserted in the ignition to drive off.....other wise the steering wheel is still 'locked' (as in 'can't be turned'). Also you can't shift the cars into gear without depressing the brake pedal....and if you depress the brake pedal without the key in the ignition, the engine shuts off instantly. Oh, and if you use the remote start, it automatically locks all the doors if they weren't already....of course we always keep the doors locked unless we are with the car.

We also use the remote starter in hot weather to cool the car down for a few minutes before getting in.....beats the heat!

 

[TromboneAl]

I've considered giving out this pamphlet when I see someone leave their car running when they go in a store. I saw a cable guy leave the van running for 45 minutes -- said he had to charge his cell phone.

Haven't done it -- a little too curmudgeonly, even for me.



Should I Let the Car Motor Idle When Not Driving?




HERE'S THE RULE OF THUMB: When you're in a drive-through line, waiting for someone, or popping in to a store – if you'll be sitting for 10 seconds or longer... turn off your car's engine.
Why??

For every two minutes a car is idling, it uses about the same amount of fuel it takes to go about one mile. Research indicates that the average person idles their car five to ten minutes a day. People usually idle their cars more in the winter than in the summer. But even in winter, you don't need to let your car sit and idle for five minutes to "warm it up" when 30 seconds will do just fine.
But you're not going anywhere. Idling gets ZERO miles per gallon.
The recommendation is: If you are going to be parked for more than 10 seconds, turn off the engine. Ten seconds of idling can use more fuel than turning off the engine and restarting it. And when you start your engine, don't step down on the accelerator, just simply turn the key to start.
Here are some other Myths associated with idling:
Myth #1: The engine should be warmed up before driving.
Reality: Idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is to drive the vehicle. With today's modern engines, you need no more than 30 seconds of idling on winter days before driving away.
Myth #2: Idling is good for your engine.
Reality: Excessive idling can actually damage your engine components, including cylinders, spark plugs, and exhaust systems. Fuel is only partially combusted when idling because an engine does not operate at its peak temperature. This leads to the build up of fuel residues on cylinder walls that can damage engine components and increase fuel consumption.
Myth #3: Shutting off and restarting your vehicle is hard on the engine and uses more gas than if you leave it running.
Reality: Frequent restarting has little impact on engine components like the battery and the starter motor. Component wear caused by restarting the engine is estimated to add $10 per year to the cost of driving, money that will likely be recovered several times over in fuel savings from reduced idling. The bottom line is that more than ten seconds of idling uses more fuel than restarting the engine.
Myth #4: If I'm charging a cell phone or other devices, I need to keep the engine running.


Reality: Charging a cellphone takes so little energy that it's virtually impossible to run down a healthy car battery by doing that. And the battery will itself the next time you use the car.

If you shut off your motor, you'll save money, reduce pollution, contribute less to global warming, and decrease dependence on foreign oil. There are no downsides to shutting off your motor.​

 

[aaronc879]

Good points Al. I was referring more to the risk of theft or other crimes however. Stopping your car at a convience store to get a pack of smokes or a lottery ticket and leaving it running. It only takes a couple seconds for someone to drive off with it or go into the back seat. It's not worth the risk. Always turn your car off AND lock all doors even if only away for a few seconds.

 

[Sam]

Al,

Good thing you did not distribute those.

For every two minutes a car is idling, it uses about the same amount of fuel it takes to go about one mile.

How did they come up with this number. It's totally arbitrary. And it's too high for current cars.

Fuel is only partially combusted when idling because an engine does not operate at its peak temperature.

Only true for the first few minutes after the vehicle is started. Todays' car always operate at optimal temperature, idling or not. Engine coolant is not circulated until the engine gets hot. And the radiator fan is not turned on until the coolant gets too hot.

Sam

 

[W2R]

There was a local news report warning people not to leave your car running unattended. Apparently a lot of people leave their cars running unattended to keep it warm this time of year. Locally it's against the law to do so because it a risk of auto theft(duh). Does anyone leave their car unattended and running when they go into the gas station or post office etc? I'd never even consider leaving it running. In fact, I lock the doors anytime it's out of my sight even if just for seconds.

Me, too. Even though the New Orleans area has an abysmally high crime rate, my car has never been stolen and I'd like to keep it that way!

I can't IMAGINE leaving the engine running while going into a convenience store, or leaving the keys in the car for any other reason. Who would do such a thing? I can't imagine. They must think they are living in Mayberry in the 1950's.

Before driving, I only run my Solara for the length of time required to fasten my seatbelt, adjust the radio, and so on. That probably takes no more than the 30 seconds listed in T-Al's post. It is almost nine years old and doesn't seem to have developed any problems.

 

[jambo101]

I was referring more to the risk of theft or other crimes however. Stopping your car at a convience store to get a pack of smokes or a lottery ticket and leaving it running. It only takes a couple seconds for someone to drive off with it

We use to use this method of getting around the city when i was much younger,we wouldnt have to wait long at a convenience store before a lazy some one would leave their car running and go into the store where upon we would jump in the car and drive close to our destination then abandon the car,much cheaper than a taxi.

 

[saluki9]

Warming up the car is some sort of modern folklore.

The air temp her in Chicago, not windchill but actual air temperature was -16.

I admit to starting my car when and leaving it sit at my office to warm up. It was so cold last night I could hardly even shift the gears because the tranny fluid was like a slurpee.

 

[cantlogin]

My opinion is that severe weather is a special circumstance where idling can be justified by the operators personal preference for comfort. A failing starter or battery could be additional temporary special circumstances to explain idling. Beyond those situations, I cannot think of any reason to allow a modern engine to run unnecessarily. An outstanding demonstration of stupidity can be witnessed by observing someone idling their engine at the pump island while refueling. I have noticed that there seems to be a strong correlation between refusing to use seat belts and excess idling.

 

[Khan]

My opinion is that severe weather is a special circumstance where idling can be justified by the operators personal preference for comfort. A failing starter or battery could be additional temporary special circumstances to explain idling. Beyond those situations, I cannot think of any reason to allow a modern engine to run unnecessarily. An outstanding demonstration of stupidity can be witnessed by observing someone idling their engine at the pump island while refueling. I have noticed that there seems to be a strong correlation between refusing to use seat belts and excess idling.

I could see that for extreme cold. But lots of locals start the morning warm up at around freezing.

Anecdote: When I was living in Detroit, a coworker left the car running (unlocked, lights and wipers on) while she went to get cigarettes; it was gone when she came out. She seemed surprised.

 

[lets-retire]

Al,

Good thing you did not distribute those.



How did they come up with this number. It's totally arbitrary. And it's too high for current cars.



Only true for the first few minutes after the vehicle is started. Todays' car always operate at optimal temperature, idling or not. Engine coolant is not circulated until the engine gets hot. And the radiator fan is not turned on until the coolant gets too hot.

Sam

I think your opinions can be debated. Everything in that flier is vehicle dependent. Obviously a big V-8 uses more gas than a little Toyota Yaris. So the Yaris might not use the amount of gas stated in the flier, but the V-8 probably does. When we figured our engine use (for vehicle maintenance) with the PD I worked at, the standard advice from Ford was 35 miles for every hour of idle time. Which is very close to the amount stated in the flier. Those engines were small V-8s.

Transverse mounted engines do have thermostat regulated fans. Many "traditionally" mounted engines still use a belt to drive the fan (it's cheaper and more efficient), so it's running if the engine is on.

Going with the odds I think the flier is valid. Most Americans still drive a truck or large SUV. The F-series truck was still the best selling vehicle in America last year and IIRC the last 27 years.

 

[Walt34]

If I'm not in the car the key is in my pocket.

Let it run for 30 seconds after a cold start to get the oil pressure up then go. 90% of the engine wear happens in the first 30 seconds after a cold start so keep the load off it during that time.

 

[ls99]

True for fuel injected engines. My 99 Sub with its monster engine is start and drive off. My old 79 chevy pickup with carburator for air fuel input was a dog to start at anything below 30F. Needed at least 5 min of coaxing to keep running before considering driving off.

That old pickup, I could leave it with the keys in it running, downtown Baltimore. It would run out of gas, no one would take it. I tried.

Now my other wheels, I always yank the key and lock.

So it depends.

 

[Alan]

Last week's Car Talk had a discussion of the need to warm up a car in cold conditions before driving off. Their opinion is that modern engines with the light, synthetic, oil they use actually require no warm-up at all, but if you insist on warming the engine then 30 - 60 secs will do no harm.

As for OP's original question, I never leave the car unlocked when I go into a store, and certainly don't leave it running.

 

[Meadbh]

Around here, when it's cold, you plug in your car! It's been so cold here recently that even then, the engine groans when started in a windy exposed car park. I like to drive away quickly, but until the heater kicks in, the windows freeze up with condensation from my breath, so yes, in exceptional cold, I do have to run the car for a few minutes. But I sit in it. I would never walk away and leave the keys in the ignition. At home, there is no problem since the garage provides excellent shelter from wind.

I did have a girlfriend who left her car running while she ran into her house for something she had forgotten. When she emerged two minutes later it had been stolen.

 

[FIRE'd@51]

HERE'S THE RULE OF THUMB: When you're in a drive-through line, waiting for someone, or popping in to a store – if you'll be sitting for 10 seconds or longer... turn off your car's engine.

Correct me if I'm wrong, but I seem to recall once reading that starting a car uses about 2 ounces of gas. A gallon is 128 ounces, so this would be 0.016 gallon. At 25 mpg, this would be 0.4 mile, so it seems to me that the break-even time (in terms of fuel usage) would be more like one minute, not 10 seconds.

 

[freebird5825]

Good points Al. I was referring more to the risk of theft or other crimes however. Stopping your car at a convience store to get a pack of smokes or a lottery ticket and leaving it running. It only takes a couple seconds for someone to drive off with it or go into the back seat. It's not worth the risk. Always turn your car off AND lock all doors even if only away for a few seconds.

I second this, and would add that it is smart to lock your doors immediately upon entering the vehicle, especially for women. I've had people walk right up to my car in busy parking lots while I am in the car, then just continue walking by. Glad my doors were locked!
Please correct me if I'm wrong, but I think insurance companies may not cover the theft is you contributed to the risk of theft, i.e. left the keys in the car. Yay or nay?

 

[ERD50]

I agree that T-Al's numbers are suspect, but generally true. And people do often idle their car far too long.

I wouldn't post a note on a car though - too many mitigating circumstances. If you just got your car started, and it barely turned over, or you needed a jump, you probably don't want to risk turning it off for a short run into a convenience store or something.

With the recent cold snap here, news stories were saying that shops were running out of batteries, so someone might not even have the choice to replace theirs. DW's battery was shot, had to shop around to find one ( which was OK, got it at Costco, best price and 3 year 100% warr - I had read earlier that Costco didn't have the top rated batteries, but we prob won't even keep this vehicle another 3 years).

If you shut off your motor, you'll ... contribute less to global warming,

I dunno T-Al, with the recent cold-snap here, that "advice" might be counter-productive

PS: My BIL would routinely go out to "warm up the car", and then come in and gab for at *least* another hour before leaving. But that's BIL's for you.


-ERD50

 

[TromboneAl]

These are the things I've seen:

Guy pulls in to campground office to get out and ask about campsites. His car is running the during the entire 15 minutes he waits in line and talks.

Woman leaves her car idling while she goes into an ice cream shop, waits in line and buys ice cream.

Guy stops to talk with neighbor through the window before pulling into his driveway. Talks for 20 minutes with engine idling.

Long line of cars waiting by the flagman during road construction. Five minute wait, all cars idling entire time.

So what are these people thinking? My guess is that most are just ignorant. Perhaps some are too lazy to turn the key??

Did I say "global warming?" I meant "climate change."

 

[Bestwifeever]

During the past week we started our bigger car twice a day and let it run about 15 minutes each time--because we were not driving it otherwise and we wanted to keep the battery (only a month old) charged. Now I'm wondering if this was wrong in terms of the battery?

Also, why do trucks at rest-stops on the Interstate keep their engines running for hours at a time (I assume there are different economics/mechanical systems at work for these big guys)?

 

[Sarah in SC]

Diesels like those big ones in the trucks are a different story. They can run longer, but it is still a big waste of fuel to leave them running all day/night not in use.
Our old diesel sedan takes a long time to warm up as well.
And the tranny in my old gasoline 1984 pickup truck is so bad, that if you want to go in reverse, you'd better plan on waiting at least 5 minutes after cranking!

 

[noworkethic]

When semis in truck stops are running for hours it is usually so the driver, who is often sleeping, can have heat or air conditioning.

 

[Rustic23]

Article in the Houston paper about three years ago about not going out in the morning and warming up your car. Thieves wait in the neighborhood for someone to do this and then drive the car away.

 

[OAG]

I remember Alaska in the 70's. We had a post in front of every parking place and you plugged in your car. You used either a dip stick heater or a pan heater. I had a VW Bus at the time (pan heater mounted under the engine), had to park head in, and make sure I put it into reverse before getting out or it would take about a half hour before you could shift the transmission into reverse. Also had to use a gasoline heater mounted under the rear seat. And this was Anchorage, Alaska (Central to Northern Minnesota like temperatures), up in Fairbanks they left vehicles running almost all the time (-50 will do that). Of course back then we were paying about $.30 cents a gallon for MOGAS.