can a car start without starting for years

[VonJuliana]

Yes, a car can start after sitting for years, but it's highly unlikely to do so safely or reliably without significant preparation. The success depends on the vehicle's condition, storage environment, and the specific mechanical issues that arise from long-term dormancy. The primary obstacles are a dead battery, degraded gasoline, and various fluids that have broken down or contaminated their systems.

The most immediate problem is the battery. A typical 12-volt car battery will self-discharge and become permanently dead within a few months if not maintained. Even if jump-started, its ability to hold a charge will be severely compromised.

Old gasoline is a major concern. Today's ethanol-blended fuel begins to degrade in as little as 30 days, forming a sticky varnish and gum that can clog fuel injectors, fuel lines, and the fuel pump. After years, the fuel may have separated and lost its combustibility. Attempting to start the engine with bad gas can cause expensive damage.

Other critical checks include engine oil, which may have drained from critical components, and coolant, which may have lost its anti-corrosive properties. Tires are likely to have flat spots or dry rot, making them unsafe to drive. Seals and hoses throughout the engine bay can dry out and crack.

Component	Potential Issue After Years of Inactivity	Recommended Action
Battery	Complete discharge, sulfation, unable to hold a charge	Replace with a new battery.
Fuel	Degraded, varnish formation, clogged fuel system	Drain and flush the entire fuel system; replace fuel filter.
Engine Oil	Contaminated with moisture, lost viscosity	Change oil and oil filter before attempting to start.
Coolant	Loss of anti-corrosion properties, potential for freezing/overheating	Flush and replace the coolant.
Brake Fluid	Hygroscopic (absorbs moisture), leading to reduced braking performance and corrosion	Flush and replace brake fluid.
Tires	Dry rot, flat spots, unsafe at speed	Inspect for cracks; likely need replacement.
Brakes	Rusted rotors and calipers, seized components	Professional inspection; components may need cleaning or replacement.

The safest approach is not to simply turn the key. Have the vehicle towed to a qualified mechanic for a thorough inspection and recommissioning. This process will address all critical systems and ensure the car is safe to drive.

[RobertMarie]

I tried to start my dad's old truck after it sat in the barn for five years. The battery was totally dead, so we hooked up jumper cables. It cranked over really slowly but wouldn't catch. A mechanic friend told us the gas had turned to junk and was probably gumming up the works. We ended up having it towed to his shop. He had to drain the tank, replace a bunch of parts, and put in a new battery. It was a much bigger job than we thought.

[StJulianna]

From a technical standpoint, an engine requires three things: compression, spark, and fuel. Long-term storage directly compromises the latter two. The spark is hindered by a depleted battery, while old fuel fails to combust properly. Even if it starts, internal components may lack proper lubrication, leading to premature wear. The immediate goal shouldn't be starting the car, but a systematic recommissioning of all fluids and a inspection of critical safety systems like brakes and tires before the engine is even cranked.