How much fuel does the average 4,6, or 8 cylinder passenger car consume per hour when left idling?

Question

Sometimes I leave my car idling in the parking lot while I am in a store for a quick 10 minutes or so...and I would like a way to calculate how much fuel I am wasting at each stop...

Okay...looks like from the answer below UPDATE ...IF you spent $3.00 for your gallon of gas and let your car idle for 30 minutes, then you would be wasting 1/10th of 3.00 so about 30 cents. So that would be 1 cent per minute. But this is not the main problem. The problem is that for every gallon of gas you burn, you CREATE 20 pounds of CO2 carbon dioxide emissions.

Answer 1

"Is it more economical and fuel-efficient to leave my car running for a few minutes than to constantly turn it off and on?
No. If you’re going to be stopped for more than 10 seconds (except in traffic), you’ll save fuel and money by turning off the vehicle and then restarting it when you’re ready to drive again. Every 30 minutes of idling costs you nearly one-tenth of a gallon in wasted fuel – and more than three-tenths of a gallon if your vehicle has an eight-cylinder engine. As well, restarting a car many times doesn’t wear out the battery and starter motor too soon. And catalytic converters stay warm for up to 25 minutes after you turn off the engine, so frequent stops and starts don’t produce the large amount of harmful emissions seen with cold starts. There’s no question about it – idling gets you nowhere. Instead, it wastes fuel and money and damages the environment."
http://www.hcdoes.org/airquality/Anti-Idling/IdleFAQ.htm

Answer 2

Letting a car sit idling, if it's in good running condition, won't do any damage. It will just waste alot of fuel. The biggest problem you run into is that there is no air moving over the radiator. Usually there is an electric fan that turns on if the car gets too hot and it solves that problem. If this fan was not working ( something you may not notice if you drive on the highway alot), the engine could overheat. If the engine overheats, bad things happen. The heads can actually warp from getting too hot and you can blow a head gasket. Check two things on the car before you try and start it again. Check the oil. Not only for level but also look for a milky gray substance. This would mean you have coolant mixing with the oil ( blown head gasket). Also check the radiator expansion tank for signs of oil in the coolant. This is that white tank that sits near the radiator and usually has some green antifreeze in there. If you have checked both of these thigns and you don't see any problems, you are probably OK, but you should still do a compression check to be sure. A mechanic can do this for you.

Answer 3

Leaving your car idling is not a good idea for first and foremost its an open invitation to have your car stolen(so far you've been very lucky) and since this appears to be a habit of your suppose there's a child,pet in the car and out of Habit you leave the car running-a potential car jacking which could have devastating consequences for you. As far as gas usage took a peek at some of the other answers and not drastic for approx 1/3 of a gallon but since you're paying close to $3.00 a gallon can be expensive idling-there's also the wear on your engine-ever notice if you have a temperature gauge that the longer you idle the hotter the car gets and in my opinion the most important reason not to is you are putting exhaust and fouling the air every time you idle and why contribute to this very serious and very real problem. The car because it runs on gas(oil) is t the top of being the villain that causes Ozone Layer destruction,the warming of the planet and so on so why not be responsible in caring for and loving the earth. You can turn off your car engine which is a relatively small thing to do but so important-what you can do to save the earth.

Answer 4

A gallon of gasoline weighs 6.2 pounds, consisting mostly of carbon, plus a small amount of hydrogen and a few impurities. Through combustion each carbon atom combines with two atoms of heavier oxygen atoms, resulting in about 19.8 pounds of carbon dioxide in the atmosphere. The 'extra mass' comes from the atmospheric oxygen which joins with each Carbon atom in the gasoline. Vehicles burn more fuel or less depending on how many cylinders the engine has inside it, usually the more cylinders the vehicle has, the more fuel it uses. Estimating for a 4 cylinder engine, your car gets perhaps 25 miles to the gallon on the highway. If the highway speed is 60 mph, this means you would burn about 2.4 gallons an hour, during which time you are probably using moderate-low throttle. If the car uses 25% of this rate at idle, you burn about 0.6 gallons an hour or 0.01 gallons a minute. Quickly multiplying by 10 - we find that you are burning 0.1 gallons of fuel in your 10 minute stop which means your engine is producing 1.98 pounds of carbon dioxide over that period of time.
If you drive a car with much worse gas mileage - like an SUV or truck, or a Van or RV the amount of carbon dioxide could be multiplied by a factor of two.

Answer 5

Let me get this straight. You are leaving the keys in the ignition and the car running. The door are probably unlocked because you can't lock the door with the key in the ignition unless you have an older car. Which you probably do since it wasn't stolen while you were gone. This means your combustion efficiency is not as good as it should be and your catalytic converter is probably not working.

Given the rate of consumption of gas , factor in the reduced efficiency which means more CO not CO2 I'd say for your car 20 lbs of CO2 per gallon is probably way high. CO however is much worse on the environment than CO2.

But on the other side of the coin you probably don't even think about comprehensive coverage on your car so you save much more in insurance than you waste in gas.

Still shut off your motor and remove your keys. You wouldn't want to have someone hurt trying to steal you vehicle.

Answer 6

Leaving your car idle might make sense if it were a diesel and it were cold outside but it's better to turn your car off. The only thing you're possibly saving is wear on the starter. One of the big fuel savings for hybrid cars is that they don't use gas or the engine in stop and go traffic (where most of the fuel is wasted). Some newer cars have the ability to shut off some of its cylinders if they're not needed.

Answer 7

The specific fuel consumption of a car is worked at the time of designing and later on by tests ascertained but for certain agreed parameters of road. While it is idling yes it is worked by the manufacturer and you can get it from him.
But the following points need considertation:
1. Ten minutes is too long a period for a car to be kept idling.
2. Restarting conditions of the car in cold and hot conditions.
3. Condtion of the battery.
4. Finally to work out the fuel consumption correctly the rpm of the engine and rate of fuel injection are required.
Ramachandran v.

Answer 8

It will consume less fuel than shutting the engine off for 10 minutes then restarting it! Yes, it is true. Ramachandran v you are just pretending to be smart. What an idiot! How is the (While it is idling yes it is worked by the manufacturer and you can get it from him.) going to tell you how much fuel that you are burning if they are stuck behind their desk, and not sitting in your car, and secondly, the battery has absolutely nothing to do with the combustion process!

Answer 9

So I just have to say, aside from all the other responses you people gave, did this person ever say they left their car unlock?? Have you never heard of remote start and keyless entry? Furthermore, it is very possible to leave you car running and lock it. So how about back to the question and stop worry about the car being stolen. That very obviously can be prevented, running or not.

Answer 10

Your lucky you have a car when you leave the store ! Forget about " how much fuel " your burning - think about how much more your insurance will cost you for your mistake ! Not to mention you'll lose at least $ 5000 on a replacement !