What Happens if You Don’t Start Your Car for a Long Time?

Letting a car sit without starting it for a long time can cause damage that will likely require expensive repairs. However, there are times when a vehicle needs to sit without starting. If this is the case, you may be wondering how long you can safely let it sit.

It is recommended that you not leave a car sitting without starting it for more than two weeks at a time. Cars are meant to be started and driven frequently. If you go for longer than two weeks without starting your car, you could experience mechanical issues.

Read on to learn about why leaving a car sitting without starting for a long time is a bad idea.

A car being parked for a long time

Broken Down Engine Fluids

Your car relies on many different fluids to help power it. Over time, the fluids begin to break down, which means they are no longer helpful to the car. When fluids break down, it can be harmful to the vehicle. Here are some of the fluids that may begin to break down.


Bad gas can be a mechanical nightmare for a car. Typically, gas will last for between three and six months before it needs to be replaced entirely. However, the more time gas sits in the car, the less potent and combustible it becomes.

When bad gas runs through a car, there are several things that you may notice happening.

  • Check engine lights come on.
  • Your car stops during acceleration.
  • Difficulty starting the car

If you notice any of these things happening and the car has been sitting for a while, you need to take it to a mechanic right away. They will likely drain the tank and lines and check for engine damage that the bad gas could have caused.


Oil has a natural viscosity, making it the ideal lubricant for the parts of an engine.

It will typically last for up to five years, either on the shelf or in the car. Over time, the oil will begin to break down and lose some of the lubrication properties.

Starting or attempting to drive a car with bad oil is not a good idea. Some of the things you may notice with bad oil are:

  • Strange engine noises
  • The oil light on the dashboard
  • Hot running car

All these things indicate a big problem and need to be dealt with immediately to avoid significant damage.


When left sitting too long, coolant can become bad in a car. When coolant becomes bad, it increases the level of acidity. Increased acidity will cause catastrophic damage to the car’s engine because it will cause corrosion to occur. Many parts of your vehicle can be damaged by excess decay.

  • Radiator
  • Heater
  • Water pump
  • Coolant lines

The expense of replacing any of these things is high, so it would be best to avoid unnecessarily damaging them.


The integrity of your brakes is one of the most important things to focus on in a car.

Brake fluid is a substance that begins to go bad as soon as it is exposed to air, which means brake fluid that has been sitting in a car for any length of time should be changed right away. Over time, brake fluid can go bad, which will cause the brakes to stop working. Here are some signs your brake fluid has gone bad.

  • Burning smell
  • Brake warning lights come on
  • Brakes that feel unsteady
  • Inability to brake properly

Some of these indicators can also tell you about other brake issues, but if your car has not been started for an extended period of time, bad brake fluid is likely the cause.

Bad Battery

Car batteries don’t do well sitting without use for long periods. Over time, a car battery will slowly lose its charge.

When this happens, the car will be resistant to start. As the car struggles to start, it will, in turn, drain more of the battery’s limited charge.

Recharging the Battery

Sometimes you may be able to effectively recharge the battery by giving it a jump start, so a replacement isn’t necessary.

If the battery of the car is around five years old, it may be more effective to purchase a new battery for the vehicle, as the battery’s life is coming to an end.

DIY Fixes for a Dead Battery

Perhaps you don’t want the expense of a new battery for your car, and you are willing to try other methods to get the battery back in working order. The good news is there are some things you may do that could revive the battery, but they are not guaranteed to work.

Sometimes, the cells of the battery have begun to dry, which will cause it to no longer work. If this is the case, you may be able to add either an Epsom salt and distilled water solution or a distilled water and aspirin solution.

Once you have made the solution, you will want to slowly add it in equal parts to each of the battery cells.

You need to be careful not to splash any liquid out of the battery when you do this. Remember, battery acid is highly corrosive and could cause injury. If you are unsure, having a trained and certified mechanic do it instead is always the safest option.

Clogged Filters

The car’s air filter commonly gets filled with pollutants and other particles of dirt from regular driving. When a vehicle sits without being used for a long time, the air filter can gather other dirt and dust that is never cycled out or pushed through the filter.

If you try to drive a car with a dirty air filter, you are risking damage to the engine. The air filter’s job is to block dust and dirt from getting to the inner workings of the engine. If the filter cannot do its job, the engine can become dirty and unable to work correctly. This can be expensive to repair.

Broken Starter

Over time, the starter of a car can begin to deteriorate whether it has been driven or not. If you have checked the battery and it is charged, but the car won’t start, you may want to look at the starter. Sometimes the starter will make an obnoxious squealing noise or clicks when you turn the key or push the ignition button. Other times it will remain silent. These could both be indicative of a bad starter.

Faulty Fuel Pump

A car’s fuel pump is a unique mechanical feature and requires running to maintain function.

It is essential to know that the operation of a fuel pump is based on pressure. If a car is not turned on for an extended period, the pressure can drain from the fuel pump, making it unusable. If the pump cannot move the gasoline through the car appropriately, it will not run.

Clogged Fuel Injector

Remember, gas begins to break down over time, and the fuel injector is responsible for the combustion of the gas. After a long time of not starting the car, old fuel can get trapped in the injector and cause sediment to form or even cause rust to develop. When these things are present in a fuel injector, it is unable to do its job correctly.

If you have clogged fuel injectors, you don’t need to replace the parts immediately. In fact, it isn’t recommended that you replace them unless necessary. You can choose to clean the injectors or take the car to a mechanic to have it done. There are ways to clean the injectors while in the car, but it is most effective to remove them altogether, especially after sitting for an extended period of time.

Problems With Animals

If a car has been sitting for an extended period, there is a good chance that animals have found a home under the hood. Unfortunately, this can be very problematic. The cost to make the necessary repairs can be high. Here is what you should look for to determine if you have guests.

Grass, Straw, or Leaves

If the car has been stored outside, it is common for leaves and grass to make their way into the car, but there should not be an excessive amount deposited. If you lift the hood of the car and notice a large amount of these items packed into the crevices of the engine, it may indicate animals have carried it there.

Chewed Lines

Animals love to chew wiring in cars. Sometimes they are attracted to a compound that makes up the plastic coating, while other times, they are trying to gather items for their nest. Check all the lines and wires carefully for bite marks.


You may also find actual nests under the hood of the car. If you happen to find a nest, you will want to do a thorough check of the engine to make sure there are no living creatures remaining.

If you notice any evidence that animals were once present or are currently present, you need to enlist the help of a mechanic to check all components of the engine. While it may seem easy to clear animals out on your own, it can be challenging because they can get into small crevices that are not easy to see.

How Quickly Does This Happen?

After reading all the things that can happen if you leave your car for an extended time without starting it, you may be wondering how long it takes for this damage to occur.

If you are going away on vacation and your car won’t be able to start for two weeks, you likely don’t need to worry about anything. However, if you are planning a trip that is a month or longer, you will want to find someone to start and maybe even drive your car to keep everything working. It is unlikely that you will experience significant damage even sitting for a month, but it isn’t wise to take the risk if you don’t have to.

What to Do If You Aren’t Starting Your Car for a While

Perhaps you need to have your car sitting without being started for an extended period of time. If you know this is the case, you will want to plan and take the following precautions to protect the integrity of your car:

  • Change the oil.
  • Fill the tank with fresh gas.
  • Inflate the tires.
  • Top off all the fluids in the car.
  • Disconnect the battery.
  • Cover the car.

While these things will help maintain a car that is sitting for a long time, it is best to have a trustworthy person to check on and start the car each week. Just because you take care of each of these items before letting the vehicle sit does not mean no problems will crop up.

Final Thoughts

If you can avoid letting your car sit for longer than a week or two without being started, it is best.

However, if you have to travel and cannot use your car, careful preparation will offer you a chance at the best-case scenario. Failing to plan and prepare your vehicle could lead to damage and expensive mechanic bills.

Related: What Should RPM Be When Starting a Car?

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