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Is it bad for the car to start it up in the morning, spend 10 seconds driving it out of the garage, then shut it off while I go close the garage door and then a few seconds later get in and start it up again and drive to work?

I know hybrids and some conventional cars start/stop the engine frequently when engine power isn't needed (but I'm not sure if they turn off a cold, just-started engine), but my conventionally powered 5 yer old car was probably not designed for frequent restarts. I've read that cold starts cause the most wear on the engine and I'm doing 2 cold starts in a row.

I do the same thing when I come home - drive up to the garage door, turn off the car to go open the door and then restart. But at least then, the engine is warm so I think it's not as hard on the car.

Am I likely to see any shorter lifetime of the engine, starter or other components?

4 Answers 4

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Yes, cold starts are hard on engines, this is very common advice. Restarting the engine when you get home should be less of a concern though since the engine is already warmed up. If all you're doing is getting out of the car to close your garage, just leave the engine running, you're not saving yourself any gas by starting it twice.

Not only will doing this shorten the life of your engine and use up more gasoline, the wear and tear you cause your starter will double if you're using it twice as often. You're probably also shortening the life of your battery by draining it more.

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  • I'm not interested in saving gas (well, I am, but that's not why I turn off the car before getting out to close the garage door), I'm interested in keeping my car. Idling cars are stolen from time to time in my area and there's quite a bit of foot traffic in front of my house.
    – Johnny
    May 21, 2013 at 21:53
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    If you have to choose between possibly shortening the life of your engine a little and having your car stolen all together, you'll have to pick your battles. Though I would suggest using two keys. Leave one key in the ignition with the car on, and use the other key to lock/unlock the car while you go to close the garage. May 21, 2013 at 22:01
  • Unfortunately, my driver's door lock is broken so I can't lock it with the key, and I can't use the alarm remote to lock the doors with the ignition key on. The battle I'm considering is trying to get my landlord to pay for, or at least split the cost of a garage door opener. If everyone here said "Oh no big deal, it does no harm at all to the car", I'd be less worried about it.
    – Johnny
    May 21, 2013 at 22:11
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    What is this place you live where people are just standing nearby waiting to jump into your drivers seat as soon as you turn your back to close a door?? May 22, 2013 at 18:07
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    @Johnny: You could always lock it by pressing the lock from inside the vehicle before you close the door, then just unlock it with the remote. May 23, 2013 at 21:54
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As Hillsons said, cold starts are hard. So are warm starts, but to a lesser degree. The engine has no oil pressure when off, and starting it again causes very slight but very bad metal on metal contact. When warm this is much less contact than when cold, as the oil is usually primed and circulated. When cold the oil settles a bit and moves away from bearings.

If you are really interested, you can get a "Turbo timer". It keeps the car running when the key is removed. They are tied to the parking brake or other systems so that if the car moves at all the engine shuts off. It would be perfect in your situation.

It's "meant" for turbo cars to allow the car to keep running for a set period of time after you walk away and lock the car, so that the turbo can cool off after a hard run. They are pretty much superfluous even with their main intention, but for you it would work well if you are willing to plop down the cash. You'd also have to see if any are available for your vehicle, or if any universal one would even work.

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Apart @hillsons answer, starting the engine frequently consumes a lot of electricity from your battery. The battery wears down much faster when it's often discharged and recharged again. I heard short battery life is a common issue in cars with automatic start/stop fuel saving mechanisms.

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Google says its best to turn it off after 10 seconds then to let it run. Leaving key in wastes more gas if thats what your conserned with.

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