How bad is it to let a car idle for too long?

Question

I've heard that it isn't good for a car for it to idle for too long. I was making a cross country (U.S.) drive when I moved. I didn't sleep well one night, and was sleepy during the drive the next day. I was drinking caffeine. But I stopped at a rest stop and took a nap. It's in the middle of the winter, and I'm driving through Utah at the moment, so it's freezing. I wound up sleeping for a while, running the engine for a few moments every now and then to warm the car up. I was using my cell phone as an alarm clock. But I was so tired that I wound up dozing off while the car was actually running, and it ran for a couple of hours. I learned my lesson about sleeping in the car in the middle of the winter. I should have just called it quits that day and found a motel. But it's too late for that. My car doesn't normally idle much. I don't go through many drive thrus, and I'm not usually in gridlock traffic. So how much damage could have been done to my car by it idling like that? Thanks!

Answer 1

No Damage whatsoever.....engines are designed to run, doesn't matter if it's idling or on the highway...provided the cooling system is workng properly and most importantly the exhaust system is in proper operating condition so as not to asphyxiate you while your sleeping... You woke up so I believe it was in good working order...
Think of Police cars, they idle for long periods and then when a call comes over the radio/computer they speed to whatever scene or traffic stop they need to respond to....Then repeat the proccess, then they are retired and become what?...Taxi Cabs, where they idle for long periods and are driven by luniatics.....LOL
Don't worry, your car will be fine....

Answer 2

It is less damaging for diesel engines. Gas engines is another story. Idle speeds may not properly lubricate all of the components inside the engine for extended periods of time even if the gauge says good pressure. In electronic fuel injected engines fuel is more correctly delivered to each cylinder than in a carburetor engine. Both however run much richer at idle speeds. this can cause spark plugs to foul more rapidly as well as cause carbon build up on the exhaust valves. The richer mixture can also "wash down" the top ring of the piston causing additional wear over a period of time. / Your friend should remain with the vehicle raising the RPM to between 1000 and 1500 about every 4 or 5 minutes for 15 to 30 seconds. Do not over race the engine never over 2000 RPM. / He would be much better off for the vehicle to drive it around the block a few times as this moves the fluids in the transmission and power steering and in the differential. Even wheel bearings need to move to keep them from pitting. There is more to caring for a vehicle than just keeping the battery charged. He also needs to check the water level in the battery. He needs to check all fluid levels, oil, transmission and coolant. All is important not just the battery.

Answer 3

It is very unlikely that you could cause damage to your car by letting it idle. In fact, in cold conditions, it is probably wise to let the car idle for some time to warm up the interior. Make sure that each time you start the car in cold conditions, you let it idle for at least 10-30 minutes, to make sure you don't end up with a dead battery from repeated starts.

Regarding the catalytic converter, it is very unlikely that you would cause damage by idling the vehicle. Furthermore, it should not cost more than $200-300 to replace, and is a part that has a finite lifetime anyway.

Bottom line? Not much damage.

Answer 4

Back in the day many cars were "air-cooled vdubs, and most motorcycles still are. That means without air literally moving over the engine it would over heat. Now cars have coolant keeping the engine cool. Maybe thats where thedamaging idle myth comes from

Answer 5

*Infrequently* letting the car idle for long periods isn't damaging. Everything breaks at Point "X" and *unnecessay* idling expedites your engine to Point "X" without the benefit of any road miles. If "bad" can mean "expensive", then *unnecessary* idling means things will break sooner and that is bad.

Answer 6

Dont worry, idling can actually help sometimes, even for long periods. What you did was very good, to pull off and get rest. I drive an 18 wheeler and sometimes we idle for comfort, and during extreme cold to keep the engine and fuel from freezing. Now idling a diesel engine is actually not really good because it does cause a build up of soot, but gas-burning vehicles has a much less build up of soot, which is caught in the catalytic converter (and a normal process). I repeat, no damage was caused and its good that you pulled off to sleep rather than driving sleepy.

Another point is everytime you start a car it takes battery power ESPECIALLY more during winter, meaning its better to leave the automobile idling rather than shutting off, turning on, then shutting off etc....

Answer 7

There is a problem with letting a car idle for too long. It can damage the catalytic converter which can cost £1000 to replace.

The problem comes with the throttle plate. This is effectively a valve that opens and shuts in the intake manifold and regulates the air flow. It is attached to the accelerator/gas pedal and when the pedal is pressed, the throttle plate opens proportionally. When you floor it, the throttle plate opens 100%. However when you don't touch the pedal i.e. let the engine idle, the throttle plate almost closes- but not quite (or the engine will stall). It is only about 3% open. Under these conditions the engine has to act as a pump, effectively forcing air through in order to run.

The lack of air means the engine will be using much more fuel to run (ever wondered why you use a lot of fuel while in a traffic jam?) and this richer mixture can clog up in the catalytic converter.

If you have to leave the engine idling for any length of time then take the car for a blast down the motorway/freeway and let the engine rev to 5500-6000rpm so the unburnt fuel deposits will be blown out of the system- you will see a cloud of black smoke coming from the exhaust. This is a good sign and will hopefully save you the cost of a new exhaust.

Apologies if this sounds a bit long winded. The chances are your car is okay. If you HAVE to let it idle for long peroids, just remeber to drive it hard afterwards. Happy christmas.

Answer 8

Don't pollute so much. It's disgusting. Some of the poisons produced by burning gasoline:
Benzene – HIGHEST SAFE EXPOSURE LIMIT = ZERO. Known to cause cancer, bone marrow defects, anemia, and DNA alteration.
Formaldehyde – Known to cause cancer, reproductive problems, asthma, headaches, and breathing and awareness difficulties.
Acrolein – Causes respiratory irritation and congestion, and eye, nose and throat irritation.
Sulfur Dioxide – Causes respiratory illness, bronchoconstriction and asthma. Exacerbates heart disease, emphysema, and bronchitis.
Carbon Monoxide – Causes dizziness, nausea, vomiting, weakness and blurred vision. Can lead to heart disease and low birth weights. Deteriorates the immune system, and can cause neurological damage.
Volatile Organic Compounds – Cause cancer, liver damage, kidney damage, and central nervous system damage. Alzheimer’s disease, cardiovascular disease, strokes and dementia have been shown to be linked to exposure to these air pollutants.

Answer 9

pollution and you are buring gas at $3.00 and over a gallone. diesel can idel and does not pollut quite as much