Most people don't think about what a parked car is doing while it just sits there.

The answer is: quietly draining its battery, letting engine fluids degrade, developing flat spots on tires, and in some conditions accumulating moisture in the fuel tank.

A car left unused for weeks or months without preparation can greet you with a dead battery, a seized brake, or worse.

<h3>The Battery Is the First Thing to Fail</h3>

Modern cars are full of electronics — alarm systems, onboard computers, memory modules — that draw small but continuous amounts of power even when the vehicle is off. This parasitic drain is harmless during regular use because driving recharges the battery constantly via the alternator. But after two to four weeks without being started, most standard car batteries will be discharged to the point where they can't crank the engine.

The AA recommends starting the car once a week and running it for at least 15 minutes to allow meaningful recharging. For longer storage, a battery tender — also called a trickle charger — connects to the battery and plugs into a wall outlet, delivering a slow, steady charge that keeps the battery healthy without overcharging it.

This is significantly better than jump-starting a fully depleted battery repeatedly, which shortens battery life. For very long storage, disconnecting the negative terminal prevents parasitic drain entirely, though it will reset stored settings like radio presets and clock.

<h3>Fluids and Engine Condition</h3>

Engine oil degrades over time even without use, as moisture and contaminants break down the additive package. If the car has been sitting for several months, an oil change before resuming regular driving is a good investment regardless of mileage. Engine coolant, brake fluid, and power steering fluid should also be visually checked for level and condition before driving.

Brakes are a specific concern after extended parking. The brake rotors develop a surface layer of rust quickly — this is usually harmless and clears after the first few brake applications, producing a brief grinding or scraping sensation. However, if the parking brake was left engaged for weeks, the brake pads can bond to the rotors, creating a more serious situation. Experts advise against using the parking brake during extended storage for exactly this reason.

<h3>Tires Need Attention</h3>

Tires lose pressure naturally over time — roughly one PSI per month under normal conditions, more in cold weather. Check pressure at all four tires before driving, and inflate to the manufacturer's recommended level found on the door jamb sticker.

Tires left sitting under the vehicle's weight in one position can develop flat spots — areas of stiffness that cause a thumping sensation during the first few miles of driving. These usually resolve as the tire warms up, but severe flat spots in tires that sat in cold conditions for months can be permanent.

<h3>After Starting</h3>

When restarting after extended storage, idle for a minute or two before moving to allow oil to circulate fully. Drive gently for the first few miles to give all fluids and mechanical systems time to warm up and reach operating temperature.

Check the brakes carefully with a low-speed stop before any normal driving. Top up the fuel tank if it's been sitting low — partially empty tanks attract condensation, which introduces moisture into the fuel system over time.