What is the downside of driving your car for only 30 seconds?

Just to move it out of the garage.
Turned off way before any real heat is created.
Just how bad is this?
I know engine wear is in the first few seconds.
But what else is bad about just moving the car out of the garage and then turning it off.

I’ve had engines flood out with short running times.

Start it. move it out of the shop and park it. Go back out and the engine just cranks and won’t start. Floor the gas pedal and the engine starts.

A flooded engine washes the oil off the cylinder walls and contaminates the oil.

Try to avoid short running times.

Tester

This is only a problem if you do it repeatedly without longer drives in between. Besides putting water and gas into the oil (from blowby) it wears out the battery (more drain than charging).

I agree with @texases. How often do you do this? I do it very rarely if just to move a car out of the way to get to another being blocked in. No real harm there. But to do it once or twice a day, and that’s all the action that car sees like 5 days in a row, that will do some damage.

It’s not a big deal if you don’t do it all the time. Probably more of a problem if you always do it when the engine is ice cold. Still, I doubt that you could take two engines side by side, one where this was never done, and one where this was done say, once a week, and over their lifetimes determine any extra wear or problems, all other things being equal.

The other thing that will happen if done continuously without ever driving it - is it’ll drain your battery. Starting a car really sucks a lot of juice out of the battery…And running it for just 30 seconds won’t be enough to put back into the battery what the starter took out.

If that’s the only way you drive your car, then yes, the above concerns are all valid.

However, if you mix it in with longer drives where the engine has a chance to warm up, then you will never notice a problem from it. (Perhaps your engine will only last 314K miles instead of 315K)

Cars are built to run in motion and not idle. With EFI, unlike a carb, it takes no time at all to develope maximum efficiency in fuel delivery. IMHO, it depends on how cold it actually is and how valuable saving energy is in the battery for the next start (to @MikeInNH , @texases and @JoeMario points) On a regular, spring, summer, fall day, it does no more harm then shutting it off anytime there is extended idle time. As long as it’s a regular daily driver and not some antique that sits all the time anyway, do it in good health for the car and the atmosphere. Doing it only occasionally and not excessively idling it, may extend the life. After all, you have already started the car. Idling it only increases the wear ! Idling will not magically reverse any added start up wear on everything used to start the car. In general, what do you accomplish by letting it idle ? Now, if you combined every time you had to move the car with actually driving it to run a errand or get the mail etc, things you had to do anyway, that would be best.

Since this is odd behavior, I gotta ask why? If u need to use garage, than park outside.

Odd behavior to occasionally move a car out of the garage or from one place to another ? Guess I’m pretty odd too. My garage shares space with a lot of other items I need access to. Bikes hanging overhead, gas grill, generator, lawn mower…we don’t store them all behind the car and then move them every time we drive into the garage.

This sounds like Robert Gift to me. one of his crazy questions.

You can use a block heater to minimize engine wear, it seems from my recollections to be worse during startup, ie the first 30 seconds of starting when cold puts more wear on the engine than 250 miles when warm, pre internet stuff. The other problem is you siignificantly tax the battery to start the car, but do not allow the battery enough time to recharge resulting in shortened battery life. usedenonobox and Senior gift the same? possible but sit back in your easy chair with a beer, preferably not canoe beer (as close as you can get to water) and say you are spam or let it go. I care, and will support you in your decision.

If you have a single car garage and single lane driveway, and you get home after your wife who needs to leave every morning before you do, you’ll have to do this maneuver every morning.

I am talking like every few weeks, I need to move the car around a 3-4 times for 20 seconds at a time.

As long as it's a regular daily driver and not some antique that sits all the time anyway

And that’s why I specifically if this is done without ever driving it. If you drive it occasionally - then no problem what-so-ever. If this is done 10-20 times in a row without ever driving it…then you may have to recharge the battery.

One of the downsides of short operation is that water condenses in the exhaust pipes and muffler and sticks around until you go for a long drive. If you have a stainless steel exhaust system there will not be too much rust and rot. With cold rolled steel, the system will rust out fast

On modern fuel injected cars, I wouldn’t worry too much about this, especially if you go on longer drives on a regular basis.

This reminds me of the movie Gran Torino, when Clint Eastwood would bring out his old antique car to wash it, wax it, admire it, and put it back in the garage. Maybe this behavior is not as odd as you think.

Sounds like Robert Gift to me

I drive it to work 2-5x a week, but need to quickly move it 1x a week, as well.
Seems like it’s not an issue

I guess I can sympathize. If I need to use the snow blower, I need to move the car ahead a couple feet to get the blower out. You don’t always know when you’re going to need it. So I just start the car and pull it ahead a couple feet and have never worried about it. When I’m done, I just put it in neutral and roll it back again. I’ve been doing this for over 15 years and really have never noticed any problem. I do worry about water sitting in the exhaust system though.