turn off or leave running?

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Id like opinions or better yet facts about weather its best to leave my motor running during short stints between destinations. Like running inside a gas station to buy a soda pop or pulling over to take a call etc.
Ive read that city taxi cabs never really shut down until the work day is over and ive read that starting is worse than idling for a little while. Ive read elsewhere that its the other way around. So which is best? I mean as far as wear not for gas savings or worrying about someone jacking my ride when im not looking. Thanks
 
hmm, why would you not want to save gas? and why would you not worry about someone stealing your car? do you reside in a theft proof area?

depending on the vehicle, I would think unnecessary idle could build up fuel dilution.
 
As a contrary viewpoint, UPS trucks stop their engines at every single house stop, which can be less than a block between start/stops.

I read long ago that it DOES take more gas to start an engine than to keep it running, but the break-even point is less than 30 seconds of idling.

So personally, my rule of thumb is that if Im stopping for less than 15-20 seconds, I leave it running. Ditto if it is not up to temperature yet, its really cold (though I dont purposely turn on my car to let it idle and warm up), its really hot, etc. Otherwise I turn it off. It reduces pollution, fuel consumption, etc.

Because the oil system is primed, everything is well coated (the oil isnt going to all fall out/off in a few minutes, even if the oil is full hot), the subsequent start-up wear from an additional start is minimal, IMO.
 
Originally Posted By: JHZR2
As a contrary viewpoint, UPS trucks stop their engines at every single house stop, which can be less than a block between start/stops.

I read long ago that it DOES take more gas to start an engine than to keep it running, but the break-even point is less than 30 seconds of idling.

So personally, my rule of thumb is that if Im stopping for less than 15-20 seconds, I leave it running. Ditto if it is not up to temperature yet, its really cold (though I dont purposely turn on my car to let it idle and warm up), its really hot, etc. Otherwise I turn it off. It reduces pollution, fuel consumption, etc.

Because the oil system is primed, everything is well coated (the oil isnt going to all fall out/off in a few minutes, even if the oil is full hot), the subsequent start-up wear from an additional start is minimal, IMO.


That was my understanding was well. Cold starts are where the most wear happens. For a fully warmed engine, stopping and starting is not an issue for additional wear. Plus you'll save gas.
 
If it is a few minutes, i would leave it running especially if its a hot day and you need AC.

Im not a fan of shutting off the car and turning it back on...i think that wears the engine out more. (i hate auto stop start technology that they put on cars now)

Also need to be more weary with direct injection engines as they build up carbon at a faster rate in idle.

I dont feel guilty at all letting my integra idle for extended periods of time but with my is250, i have to itch to turn it off after a minute...
 
In my work with generators the highest wear is just after start up and continues until normal temperatures are reached. After normal temperature is reached a restart is not a problem when it comes to wear.

Once your vehicle is warmed up I'd turn it off at stops to save the gasoline. Higher fuel usage on start up only applies to cold starts. Modern FI engines are very efficient during start up. My 03 V8 4Runner uses the ignition key to start the process but the CPU controls it instead of you, that is you can hit the starter and let go immediately. Your input is no longer needed.


The Prius even has a thermos that captures hot coolant and saves it for the next cold start to shorten or almost eliminate warm up time. There's nothing you have to do, the CPU controls it.
 
Originally Posted By: EdwardC


That was my understanding was well. Cold starts are where the most wear happens. For a fully warmed engine, stopping and starting is not an issue for additional wear. Plus you'll save gas.


That's how I see it.

A few minutes to get a drink or take a call should not be a problem, the engine & oil are still warm.
 
If I don't have to worry about someone stealing my car I leave it running if its only a minute or two. Any longer than that I shut it off.
 
JHZR2 said:
As a contrary viewpoint, UPS trucks stop their engines at every single house stop, which can be less than a block between start/stops.

There can be a cost with this tho=I know a fella that maintains UPS trucks and he says there's lots of starter/flexplate/flywheel/ring gear issues.
 
Whatever you feel best. Really indifferent to livespan of vehicle in majority owners possession except for the odd folks who keep cars till the grave/junkyard and have tolerance for elderly repairs.
 
It's the warm-up period that wears things out, not just the fact that it was started from cold.

Once it's warm, I don't see that there's anything really to be gained, nor lost from keeping it idling. Bad old days with carbs, there was probably a difference.

Ring gear and flexplate wear is a valid concern.

A hot start, the first few revs are probably in boundary load with a line contact until a few revs are on board in spite of the fact that oil's there.

The ring belt area will heat soak a bit more on a stop.

Personally, I'll stop them.

Every time that I keep something running because the better half is "racing in to get something", a minute or so passes and I wish I'd turned it off. Then I second guess turning it off because it can only be another second or so...then another 5 minutes goes by...I turn it off when I'm thinking straight.
 
Originally Posted By: Mrsandman
Id like opinions or better yet facts about weather its best to leave my motor running during short stints between destinations. Like running inside a gas station to buy a soda pop or pulling over to take a call etc.
Ive read that city taxi cabs never really shut down until the work day is over and ive read that starting is worse than idling for a little while. Ive read elsewhere that its the other way around. So which is best? I mean as far as wear not for gas savings or worrying about someone jacking my ride when im not looking. Thanks


In the old days with carbureted trucks the GM rep at our Upfitter used to tell us if we weren't stopping for more than 15 minutes to leave it idling. Engine life was fantastic, those old 350's would run forever.

Nowadays with all the modern engine controls there is much less to be gained. But one thing for sure, VERY little wear at idle in any modern engine...
 
The engine on a hybrid will start/stop many times per mile. Thats one way it saves fuel, and wear.
 
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Those US mail vehicles have to shut engine off at every stop and chock the wheels. Just on my street he shuts off and restarts 3 times. Im guessing he does that at least 300 times a day. On the flip side the police leave their vehicles running nonstop during a shift in fear that it wont restart for an emergency..
 
Originally Posted By: Shannow
Every time that I keep something running because the better half is "racing in to get something", a minute or so passes and I wish I'd turned it off. Then I second guess turning it off because it can only be another second or so...then another 5 minutes goes by...I turn it off when I'm thinking straight.


He, he, I've had something similar happen few times. Wife says she will only take a "minute" to pick up something so I let the car running. Two, three minutes pass and I'm thinking of shutting it off, but decide to wait since she could be coming out any second. Few more minutes pass and I shut off the car only to have my wife come out of the store shortly after
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Now I just shut the car off the moment we stop unless it's really hot and I want to keep the AC running, or really cold and heat is needed.

And in regards to OP question, I think it makes absolutely no difference to engine life except for the most extreme cases and even then, the extra wear will not manifest itself in a blown engine, like a lot of people imagine it. It will most likely be increased oil consumption and/or lower cylinder compression.
 
In most cities it is Illegal to leave a car running with no occupants inside. Leaving it idling with no one inside is good for the engine AND anyone who wants to steal it. Ed
 
Originally Posted By: Eddie
In most cities it is Illegal to leave a car running with no occupants inside. Leaving it idling with no one inside is good for the engine AND anyone who wants to steal it. Ed


Not unless you have a remote car starter installed that allows you to keep the car running, remove the key from ignition and lock all doors.
 
There's definitely some more ring gear wear. With 15-20 starts a day for the first year of its life, I am wondering how long before the Focus has a starter or ring gear failure.

With that said, modern vehicles don't use a lot of fuel idling either. But "warm" starting isn't much wear. Either/or. Less chance someone would steal it running.

Now carburetor cars are probably a bit different.
 
Warm starts do not put wear on the engine. Don"t be like the typical d-bag I see by the dozens around North Texas that leaves his giant pickup trunk running outside home depot and various groceries stores and the like. Save some gas and do the environment, your neighbors, and people around you a favor by turning your vehicle's engine when you are not in it.
 
Originally Posted By: JHZR2
As a contrary viewpoint, UPS trucks stop their engines at every single house stop, which can be less than a block between start/stops.

I read long ago that it DOES take more gas to start an engine than to keep it running, but the break-even point is less than 30 seconds of idling.

So personally, my rule of thumb is that if Im stopping for less than 15-20 seconds, I leave it running. Ditto if it is not up to temperature yet, its really cold (though I dont purposely turn on my car to let it idle and warm up), its really hot, etc. Otherwise I turn it off. It reduces pollution, fuel consumption, etc.

Because the oil system is primed, everything is well coated (the oil isnt going to all fall out/off in a few minutes, even if the oil is full hot), the subsequent start-up wear from an additional start is minimal, IMO.
That's a safety issue for UPS.
 
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