Whether the car has been sitting for a month while you were away, or half a year because you were not using it, there are things you need to check before you turn the key. A car that sits for a long time deteriorates in ways most people do not expect.
Battery - Almost Certainly Dead
If the car has been sitting for more than three or four weeks, there is a good chance the battery is flat. Even with everything turned off, the electronics in the car draw a small amount of current (alarm, computer, clock). On an older battery, a month is enough to drop below the level needed to start the engine.
What to do: Try jump-starting from another car. If it starts, drive for at least half an hour to charge it up. But if the battery has been sitting completely dead for a long time, its capacity is likely permanently reduced and it needs replacement.
Tip for next time: If you know the car will not be driven for a while, connect a trickle charger. It is cheap and keeps the battery healthy.
Tires - Flat Spots
When a car sits in the same spot for weeks, the tires deform where they contact the ground. This is called flat spotting. You will notice vibration and thumping on the first drive, especially while the tires are cold.
After shorter periods (up to two months): Flat spots are usually temporary and go away after about twenty kilometers of driving.
After longer periods: The deformation can be permanent, especially on older or cheaper tires. Before driving, also check the pressure because tires lose air even when the car is not moving.
Fuel - It Has a Shelf Life
Gasoline starts to degrade after roughly three months. Diesel lasts a bit longer. Old gasoline burns poorly, can clog injectors, and cause hard starting.
If the car sat for more than three months: The best approach is to fill up with a full tank of fresh fuel to dilute the old stuff. If it sat for over six months with a full tank, it is reasonable to drain the old fuel entirely.
Oil and Other Fluids
Engine oil that sits for a long time loses its properties. The additives break down and the oil can separate. The same goes for brake fluid, which absorbs moisture, and coolant, which gradually loses its protective qualities.
Recommendation: If the car has been sitting for more than six months, change the oil and filter before you start driving regularly again. Check the level and condition of all fluids.
Brakes - Disc Corrosion
Brake discs start to rust after just a few days of sitting, especially in a damp environment. A thin layer of corrosion is normal and comes off after a few stops. But after months of sitting, the corrosion can be deep and the pads can stick to the discs.
What to expect: The first few stops may come with scraping sounds and reduced effectiveness. Drive carefully for the first few kilometers until the discs clean up.
Rodents - the Unexpected Problem
Mice and rats love parked cars. They nest in the engine bay, chew on wiring, and gnaw through rubber hoses. Before starting the engine, open the hood and look for nests, droppings, or damaged cables.
Seals and Rubber Parts
Rubber that is not being used dries out and cracks. Gaskets, oil seals, CV boot covers - all of these can start leaking after extended storage. Check underneath the car for any signs of leaks.
Checklist Before the First Start
- Check the battery or connect a charger
- Inspect the engine bay (rodents, damage)
- Check engine oil, coolant, and brake fluid levels
- Check tire pressure
- Turn the ignition on briefly before starting (so the fuel pump fills the system)
- Drive slowly and carefully for the first few kilometers
Not Sure If Everything Is Okay?
If the car has been sitting for more than a couple of months, bring it in for an inspection before you rely on it for daily driving. A quick check can uncover problems that would otherwise catch you off guard on the road.