What To Do If Your Car Has Been Sitting and Won’t Start

If you have a vehicle that’s been sitting in your garage or elsewhere unused for a long period of time, it might refuse to start right away. There’s a laundry list of possible issues that can cause this. Today, we’ll be taking a look at all the ways you can try to revive a car that you haven’t driven for ages.

Tools To Prepare

The tools you need to prep will ultimately depend on what procedures you need to do. Here are some common items you’ll want to have on hand:

Safety Items

These are items you want for most of the jobs in this article. Staying safe should be your top priority, to be sure to have them on hand.

• Face mask
• Mechanic gloves
• Safety glasses

Also disconnect the battery and clean any spills near the battery before you begin repairs. This might not be necessary for all of these projects though, especially if you need to let your vehicle idle.

Jump Starting

• Jumper cables
• A live battery with the same voltage or a jump starter

Oil Drain and Pressure Test

• A helpful friend
• Tools as necessary
• Oil drain pan
• Oil pressure test kit
• A light
• Car jack
• Jack stands
• Wheel Chock

Battery Changing

• A new battery
• Tools to change the battery

Fuel Testing

• Fuel siphon pump
• New fuel
• Clear container
• A safe container for old fuel

Starter Motor Replacement

Typically the starter won’t go bad simply because the vehicle is sitting parked for a long time, but if the vehicle was parked because the starter was bad, here are some pointers:

• Replacement starter motor
• Jack stands
• Wheel chocks
• Car jack
• Work light
• Tools to change the starter motor

Thousands of happy customers choose CarParts.com. Shop Now

How To Start a Vehicle That’s Been Sitting Unused

Now that you have the items you need, here’re some next steps. We cover a number of these projects in their own separate articles, so these are mostly just tips and tricks. Consult your vehicle’s manual for more specific information.

General Steps for Starting a Car That’s Sitting

1. To begin with, you need to open the hood and see if there are any wasp nests, rat nests, chewed wires, or a cat asleep in the fan shroud. This is more important than you think. Anything you see along those lines needs to be handled before you even try to spin the engine.
2. Remove the gas cap and see if the gas stinks. If it does, you might need to know how to drain the fuel tank and add new fuel, but this is only valid if the electric fuel pump is locked up due to rotten fuel. If the gas seems to smell okay, put the gas cap back on and open the driver side door.
3. Next, check the inside for snakes, spiders, and other such critters you don’t want to share space with.
4. Settle into the seat if all is clear, insert the key, and switch it on. Do you see instrument panel lights? If you do, try to spin the engine over. If it only clicks or if it spins very slowly, get your voltmeter and check the battery voltage.
5. If the battery is strong but the engine spins slowly, you’ll need to remove the plugs and squirt a bit of oil into each cylinder because the cylinder walls are dry if it’s an older engine. Newer engines have low tension piston rings and the engine may spin really fast without compression for the same reason, so be aware of that.
6. Once you’ve lubed the cylinders, spin the engine again and see if it spins faster or seems to have developed some compression. If so, see if it’ll fire up and if it does, see how it runs. If it doesn’t move on to the next section.

If the car battery is strong but the engine spins slowly, you’ll need to remove the plugs and squirt a bit of oil into each cylinder because the cylinder walls are dry if it’s an older engine. Newer engines have low tension piston rings and the engine may spin really fast without compression for the same reason, so be aware of that.

– Richard McCuistian, ASE Certified Master Automobile Technician

Now here’s a look at specific tasks you may need to do depending on the condition of your car:

Oil Drain and Top-Up

Checking and changing the engine’s old oil is one of the most important things to do before starting your vehicle again. It’s good to change your vehicle’s old oil before attempting to start it. The oil might have leaked out over time or gone bad after sitting so long out of circulation. Drain the vehicle’s oil into an oil drain pan and remove and replace the oil filter. Fill the tank with new oil.

Afterwards, you can check the oil pressure to see if the engine’s seized. Lubricate the engine cylinder walls before you do this. Leave the oil drain pan beneath the engine to catch any oil spills. Remove the oil pressure sender and its connector and let the engine idle for about five minutes. After that, use the oil pressure sensor to check for the proper oil pressure range indicated in your vehicle’s repair guide or owner’s manual. Your extra set of hands can help you keep the right RPM for readings according to the test kit’s instructions.

If everything’s in order, you can return the oil pressure sender as it was. Be sure to top off the oil again if needed.

Lubricating Engine Cylinder Walls

Over time, the oil inside your vehicle’s engine cylinder walls likely slid down into the oil pan, leaving the walls dry. You should lubricate the cylinder walls before starting the engine. You can use fogging oil to spray a thin oil coat onto the cylinder walls and piston rings to keep the engine from damaging itself while the new oil gets cycled through the system. Remove and inspect the spark plugs and apply fogging oil to each of the cylinders.

Jump Starting

If the ignition’s fine but your vehicle’s hard to start, it’s possible its battery has lost charge and needs jump starting. This is much easier if you have another vehicle using a similar battery. You can use the jumper cables to attach the other vehicle’s battery to your vehicle’s dead battery. If you don’t have another vehicle nearby, you can use a jump starter box or a battery jump starter pack. Check your vehicle’s old battery to make sure it isn’t defective, and replace it if needed.

Battery Replacement

Replacing an inoperative car battery is simple. Remember to remove the negative cable before removing the positive cable. Keep note of which is which to adequately install the new battery. Remove any clamps or hold-down straps, and lift the battery out of its compartment. Don’t tip over your vehicle’s old battery to prevent spilling battery acid. Clean or replace the battery tray if it’s damaged or corroded.

Install the new battery after testing it with a voltmeter. Install the new battery and clean the posts to ensure efficient electric contact. Connect the positive cable before the negative cable this time. Tighten the battery clamps, taking care not to over-tighten them, and double-check all straps and connections.

Old Gasoline Draining

Bad gas can cause a car not to start properly. After a month, old fuel in a gas tank starts breaking down. Degrading fuel also creates a gummy residue that can make the engine misfire and stall, so replace the old gasoline in your vehicle if it’s been sitting a while. You can tell gas has gone bad by the pungent sour smell, or you can place a small amount of gas in a clear container and see if it separates into discernable layers or contains particulates.

Pro Tips are nuggets of information direct from ASE-certified automobile technicians working with CarParts.com, which may include unique, personal insights based on their years of experience working in the automotive industry. These can help you make more informed decisions about your car.

Pro Tip: Regular gasoline typically lasts about 3-6 months. Premium or high-octane fuel can last up to 9 months. Diesel can last up to a year. Ethanol-blended gasoline can go bad in 1-3 months.

If it’s been six months or longer since you drove your vehicle, it might need a full drain and refill to get rid of the contaminated fuel.

If you’re planning to leave your vehicle in storage for a month or more, add fuel stabilizer to the gas to help prevent fuel degradation.

There are fuel stabilizers that you can buy, which include mineral oil along with other additives to help stabilize fuel, clean the fuel system, and provide lubrication. There are also fuel stabilizer additives specifically for this purpose.

Starter Motor Replacement

If your car’s not starting up and is making a clicking sound when you turn the ignition, it’s possibly because of an inoperative starter motor. Rule out electrical system issues and a dead battery before conducting this repair. Also check your vehicle’s manual if you’re having a difficult time finding the motor.

While it’s mostly a matter of removing the old motor and replacing it with a new one, this project might involve disassembling lots of different parts to reach the motor. If you aren’t confident in your DIY abilities, have a trusted mechanic take care of it.

And there you have it! Our list of tips for how to start a car that has been sitting unused a long time. Remember that you can always bring your vehicle to a trusted auto mechanic if you have any worries about doing these projects yourself. It’s ultimately better to be safe than sorry.