How to safely start a car that has been sitting for years
Gasoline breaks down after six months, leaving stale fuel and carbon buildup that can damage the engine if cranked immediately. Draining the old fuel system and checking key components before turning the key prevents severe pre-detonation and engine failure.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1checking fluids and inspecting for rodent nests
- 2checking for a charged battery and cranking it over
- 3filling the tank with fresh fuel if it fires up
- 4making sure the brakes work and checking for leaks before driving
- 5Diluting old gas by adding fresh fuel and running it through the system
- 6Spraying starting fluid in the throttle body
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“What would you recommend I do to accomplish this? Any particular tools I should be sure to have on hand? Any solvents or solutions or parts I might want to bring with me?”source ↗
“Maybe it'll fire right up, but if not, how do I look like a hero in this case?”source ↗
“My mom has a 2013 cadillac ats 2.5l with about 100k miles that sat for about 2 years due to a rear diff that gave out, weve replaced the diff but i reccomended to get the fuel system drained due to the fuel most likely going bad”source ↗
“Ah, okay. Ive just heard and read that most gas starts breaking down between 6 months and a year. It already has carbon buildup issues in the exhaust and didnt want to make it worse or risk pre det.”source ↗
Where this came up
People with this problem also raised
- 2Do I need to do anything before leaving my car parked for months?
- 6Car won't start or shift gears after dead battery
- 2Why does my car go into limp mode after warming up?
- 9Car won't start after replacing ECU and electronics failed
- 8Why does my car engine cut out after driving for a while?
- 2Why did my car battery die again right after a jump start?