So I don't drive a car very often, maybe once or twice a week. And I don't usually worry about that. When, and how often should I start the car? Should let it idle every few days if I don't drive it for a long time?

But now it's very cold outside -18 and I didn't drive my car for 5 days so I am worried if my battery will end up dead if i don't start it in next day or two if it continues to be so cold.

In other hand I don't know if it's actually more hurtful to the engine if I just start it for an idle for some minutes without actually driving it a few kilometers.

In other hand my car is Alfa Romeo 147 which have so many electronic parts on it and also ecu will reset if I take the battery out.

So should I just try to test my battery if it have enough power to start the car, and leave the car to idle maybe 15 min to get the oil through all the parts to get all those rubbers and sealants lubricated.

Or will I actually hurt my vehicle more if I am starting it more often on cold weather? Will ? actually make more damage to compression and damage compression rings?

  • The ECU will reset? What happens during a normal, routine battery change?
    – MikeP
    Jan 8, 2017 at 1:16
  • During the normal routine battery change you have something like 45 min to 1 hour to put new battery once you disconnect old one. Anything more than that, the ecu will reset. Few people confirmed me that.
    – lonerunner
    Jan 9, 2017 at 11:35
  • Where is your car? In your own garage, in your driveway, 200 metres from your home? Can you plug a battery charger somewhere and run the cables to your car? Apr 26, 2020 at 21:44

2 Answers 2


Cold temperatures are bad for batteries. They lose their charge very fast.

The ideal options for you are to get an electric blanket for your battery, or keep it on a trickle charger.

As far as the rest of the car, I think you'll be okay not starting it. Just keep an eye on your fluids.

  • Yea i have one of those electrical chargers which stops when battery is charged and keep the charging level on battery, also it's kinda safe for newer cars with electronics, i can connect it directly on the battery while it's on a car. The problem is my car is now on the street so i can't get cables through my whole yard and leave charger on street.
    – lonerunner
    Jan 6, 2017 at 20:14
  • Just drive the car around and get it fully warmed up. That should be long enough to get the battery back to a full charge. If you can't do that, then remove the battery and keep it inside your house.
    – Spivonious
    Jan 9, 2017 at 16:36

The battery should be fine for the period of time you're talking about as long as the battery is in good shape. It should be able to hold a good enough charge for several weeks to start the car. If you are that worried about it, starting it and letting run for 15 minutes once a week is not a bad idea. You'll want to ensure you run it around a little at some point to get the entire engine completely hot. This will ensure all water vapors which may have collected in the oil will be evaporated out of the engine. Short trips and/or short idling of the engine can cause an excess buildup of water inside the engine. It comes from the combustion of the fuel and is normal, but without a longer heating cycle don't get the opportunity to evaporate.

When you say -18, I'm assuming you are talking about -18° Celsius. In relative terms to a car, that really isn't that cold. On the Fahrenheit scale, that's just below zero (-0.4°F). As long as you have good antifreeze in your vehicle and a good winter weight oil (5W or 0W), the engine should turn over fairly easy, but may require a bit to get it started (several crank rotations). If it gets much colder than that, I have used what's called an engine heater (can also be called a block heater). This will ensure your engine is completely warm before you go to start it. This was almost a requirement with carbureted engines, but with today's fuel injected engines is less of a necessity.

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