How Long Can I Let My Car Sit?


Often times we may find ourselves in a situation where we are unable to use our car for long periods of time for whatever reason. This especially applies to classic cars where driver’s sometimes only use them for special occasions. I’ve restored several classic cars as well as have had several daily drivers that I’ve had to let sit for a while.

So all of that leads me to think, how long can I let my car sit? If you have not taken the steps to prepare it for long term dormancy, you should never let your car sit for longer than a month without starting it up for at least 10 minutes. If you let your car sit, parts of your car will start breaking down and will eventually cause issues.

Too many times I have let my car sit for much longer than it should have, which caused other problems that I had to deal with. Because of this, I’ve been able to see first-hand what it’s like and know the right steps to take in preventing further damage to cars, whether it be a daily driver or your classic vehicle.

What Happens When You Let Your Car Sit

There are several things that happen to your car’s structure and chemistry when you let it sit for too long. Such things include gaskets and seals becoming brittle, flat and brittle tires, drained battery, gummed up fuel, rust, and engine oil deteriorating.

There are a lot of other things that can happen, but these are the main ones to be concerned about. Let’s discuss each possible issue and how/why it happens to your car when you let it sit.

Gaskets and seals are an extremely important component to a car. Without them, there would be leaks all over the place and your car would cease to function because it would run out of fluid very quickly.

If you use a rubber band frequently, their life-span is a lot longer because they’re being used for what they were made for. But if you let a rubber band just sit, it becomes brittle and will snap at any little pull. Gaskets and seals works the exact same way; when they aren’t used and exercised in a way they were meant to be used, they break down and don’t function the way they’re supposed to.

Tires on a car work similarly to gaskets and seals; if they’re not used, the rubber on them becomes ineffective. They get cracks and holes and will eventually get flat spots because air is escaping from the cracks. If you let a car sit on a flat spot on the tire, you’ll need to just throw out the tires entirely and get new ones; you cannot revive a tire with an old flat spot.

A drained battery will probably be your first issue you’ll have after letting a car sit. This is especially prevalent if you live in colder climates because batteries have a difficult time recovering from cold temperatures when they’re not used. There is also a phenomenon called “parasitic drain” which is a circumstance where the car’s computer and/or poorly grounded wires cause a slight and slow discharge over time.

Believe it or not, it is actually possible for your gasoline to go bad. If gas is not held in an air-tight container (which a car gas tank is not air tight), the oxygen reacts with the gas and destabilizes it and causes it to become a gel-like material. You may also notice a bad smell coming from your gas tank. If your gas becomes like this, it becomes unusable and you may not even be able to start your car.

Weirdly enough, rust actually forms a lot faster on cars when they aren’t used. Regularly driving your car actually prevents, or slows down, the formation of rust. This is because when cars are stationary, the oxygen and iron have a way better chance of reacting and creating rust as compared to high speed environments when the car is in motion.

The oil in your engine deteriorates a lot faster when it’s not being used. A lot of people assume that because they don’t use their car that often, especially if they have a classic car, that means they don’t need to change the oil as frequently as they would if they regularly drove their vehicle. It’s actually quite the opposite. Again, when this substance isn’t used the way it was intended to, it breaks down over time and loses it’s lubrication and cooling properties, thus giving less lube to your engine when you start your car.

How To Revive A Car That Has Been Sitting

You may be caught in a situation where you’ve already let your car sit for too long and the damage is done (hopefully not too much though). If this is the case then don’t stress too much, you’re in a majority. I’ve been there many times, you just need to be sure to do your due diligence when getting it back up and running.

There are several things you can do to revive your car if it’s been sitting for a while. The first thing you’ll want to do is assess the tires. Check the tire pressure and make sure they’re up to the required PSI stated on the sticker inside the driver side door jam or on the tire sidewall. If it’s obvious you need new ones, either use spares or take the rims off to have new ones mounted at a shop.

You’ll need to siphon out all the old gas and replace with fresh gas. Some cars, however, have an anti-siphon mechanism making this process impossible. If that is your case, you’ll need to add some fuel stabilizer to your gas and let it sit for a few hours to remove any water that has possibly built up in the gas tank. You can get stabilizer at any local auto parts store.

The next thing you’ll need to do is to start it. If the engine won’t turn over at all it’s probably your battery. Try charging it first. If it won’t hold a charge then you’ll simply need to get a new one. If you weren’t able to siphon out the gas and had to use an additive, your car may run a bit rough for a while as it works out all that gummed up fuel. The exhaust also might smell really bad, this is normal if you’re trying to run gasoline that is old.

If you are able to get it started, let it idle for 10 minutes. Frequently check underneath the car and assess for any leaks. If any of your gaskets went bad, you’ll notice some puddles underneath the car. Also monitor the temperature of the car to make sure it doesn’t over heat. If you notice the temperature is getting too high, turn on the heater and let the blower motor try to cool it down. If that doesn’t work then turn off your car immediately.

If you did notice some leaks, you’ll probably need to take your car into a shop and have them assess the source of the leaks to ensure all your gaskets and seals are performing well. If you feel confident enough to get underneath the vehicle and look yourself then go right ahead. I always do my own mechanic work unless it’s something that’s way over my head.

While you’re in the shop getting a tune up, be sure to get an oil change, or do it yourself at home for even cheaper. When I change my oil myself it generally costs me around $25 and then I know it’s done correctly. Even if you just had the oil changed right before you let the car sit for a while, it’s a good idea to get it changed any way. A good rule of thumb is to change your oil every 5,000 miles or every 6 months, whichever comes first.

How To Store Your Car For Long Periods Of Time

If you know you’re going to be storing your car for long-term, there are a few measures you can take to prevent these previously stated problems and make the process of taking it out of storage a breeze.

Top off all of your fluids including transmission fluid, coolant, and windshield wiper fluid. Also get your oil changed because your oil is still serving a purpose inside your engine.

Fill up your gas tank with fuel and then add a bottle of fuel stabilizer. Having a full tank will keep rust from forming in the top half of the gas tank, which is a common problem among classic vehicles. Normal gasoline will last about 6 months in a sealed environment before going bad. Adding fuel stabilizer can bump that up to a year.

If you have some crummy old spare tires, put those on your car to replace the nice tires you have. This will still create flat spots on the old tires, but your new tires will be saved.

You have a few choices when it comes to your battery. First, you can disconnect it from your car and bring it inside to prevent exposing it to extreme temperatures. The second option would be to hook it up to a batter tender which will automatically charge your battery when it starts losing voltage. I would always recommend using a self-shut off battery tender so it doesn’t overcharge your battery.

It is always ideal to leave your car inside somewhere such as a storage unit, garage, carport, etc. Whether you have it inside or have to keep it outside, always cover your car with a quality car cover. This will prevent dust and dirt from getting on and in it as well as prevent sun damage if it is being stored outside.

Related Questions

Can mice and other animals get into or nest in a car? It is possible for mice and other small animals to get inside your car. The possibility entirely depends on the year and make of your car and it’s structure. If you notice any trace of animals in your car, contact pest control as they can remove the animals.

Can I remove scratches on my car myself? You can remove scratches from your car yourself. Rubbing toothpaste on the scratch will sometimes work. There are also products such as scratch removers or polishing compounds that do an excellent job of removing small scratches and make your car look like new. These methods only work if it’s a surface scratch. Any scratch down to primer or metal will have to be repainted.

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