If someone is waiting, how long does it make sense to let a car idle?

Answer 1

Five to ten minutes. It is bad to shut a car on and off continuously, but to allow it to idle wastes fuel. If you're going to be waiting for more then ten minutes, I would turn the car off. Anything other than that, it will probably be easier on the car (and actually take less fuel) to allow it to idle.

Answer 2

It doesn't make sense to let a car idle at all, unless you are stranded and it is the only form of heat (still have to worry about Green House Gasses, though ... suffocation). One secret to increased mileage in Hybrids is that they don't even idle at a stop light ... the engine shuts off and restarts when needed. Running the engine in a car without moving is totally wasteful.

I am working on getting a product to market that will save you $200 a year in fuel doing things just like that, maybe even more!

If the engine was cold and dry turning it on and off repeatedly might cause some damage. If you drove somewhere and are waiting for someone, turn it off; the engine is hot and lubricated, turning it off and on won't do any harm to the engine. Many cities now have laws against allowing a car to idle more than 3 minutes. I think taxi drivers better demand cars with electric heaters and AC units!

Answer 3

Five to ten minutes. It is bad to shut a car on and off continuously, but to allow it to idle wastes fuel. If you're going to be waiting for more then ten minutes, I would turn the car off. Anything other than that, it will probably be easier on the car (and actually take less fuel) to allow it to idle.

Answer 4

I wouldn't let it idle for over a minute or two myself. With the fuel injected engines you'll save gas.

Answer 5

anything less than 5 minutes is ok ,anything over that i,ll cut it off,rather than waste gas,but it think 5 minutes is long enough ,good luck.