Road trip illustration for 360 magazine by Gabrielle Archuleta

Starting A Car That Has Been Sitting For Months

Whether you’re going on vacation for a while or temporarily relocating to another location for work, you may need to leave your vehicle for an extended period of time without using it.

If you are in this situation, it’s important to know how not driving your car for a month or more will affect its performance, including its ability to safely start.

What Happens If You Don’t Start Your Car For A Month?

Cars are designed to be driven, not to sit idle for months. When left unused, engine fluids start to break down and parts that aren’t getting lubricated begin to corrode. Even worse­–animals may move in, chewing on anything they can reach. Rodents often chew through wiring harnesses or other car parts that are made out of organic materials, which can cause substantial damage.

Tires are also affected by inactivity. When a car is not being used, the air will slowly start to leak out of its tires, especially in the cold weather. The weight of the vehicle will press down onto the deflating tires, which can cause flat spots. Filling the tires with air often solves this problem, but sometimes flat spots become permanent.

Moisture can also start to accumulate in the gas tank if the car is left unused for a long period of time. Over time, this can lead to corrosion.

How long can a car be left unused? In general, the longer a car sits, the worse these problems can become. But, it’s not all bad news.

Leaving A Car Unused For 3 Months? Here’s What to Do Before Starting It

If you plan on leaving your vehicle unused, it’s important to know how to start a car that has been sitting for two weeks, two months, or even two years.

Even after a few months, most modern cars can still be safely started. That is, providing the battery still holds a charge. However, there are a few simple checks you should make first. This will help you quickly identify problems while making sure your car is safe to start.

Here’s what to do:

Check The Engine Oil

Check the oil level using your vehicle’s dipstick. If you’re not sure where the dipstick is located, refer to your owner’s manual for a diagram. The correct oil level should be between the two indicator marks on the dipstick.

Be sure the engine is cooled off for at least ten minutes before you check the oil. When you go to check the oil not only should you take notice of the level, but also you should observe the color and consistency. If this oil is thick and gritty and the color is dark, then it’s likely time for an oil change. Be aware that if your oil level is low, you should not drive your vehicle until you have topped it off to the recommended level with the recommended oil.

Check All Exterior Lights

Check that your headlights, fog lights, high-beam lights, brake lights, reverse lights, and indicators are all working before you head out on the road. The easiest way to do this is to grab a friend or family member, so one person can activate the various lights and the other can check if they’re working.

Check For Signs Of Leaks

Before you check the engine oil and coolant levels, take a look at the floor under the car to see if there are any signs that something has been leaking. As a general rule, you can typically narrow down the issue by observing the color of leak, though it’s always best to have a professional inspect and diagnose the leak before driving:

  • Black or light brown usually indicates an engine oil leak
  • Red or brown usually indicates a transmission leak
  • Clear, red or brown usually indicates a power steering leak
  • Transparent yellow or brown usually indicates a brake system leak

Driving your car while it’s leaking fluid can cause serious (and expensive) damage. It’s important to avoid driving if there are any signs of a leak. Check for any leaks underneath your car before taking your car for a drive for the first time in months.

Check The Brake Fluid

To check your vehicle’s brake fluid level, you need to identify the brake master cylinder reservoir. It is typically mounted at the rear of the engine, in line with the position of the brake pedal. Your owner’s manual should be able to show you exactly where it’s located.

You’re simply performing a visual check of the fluid level against the markings on the translucent brake fluid reservoir. Remove the cap of the reservoir and note if the fluid looks healthy or dirty. If your brake fluid is low, it could indicate a problem with your brakes that will need repair as soon as possible. Dirty brake fluid can indicate water contamination has occurred, in which the vehicle’s brake system will need to be flushed.

Inspect The Battery

The first issue you may encounter if your car is left idle for an extended period of time is car battery problems. Batteries slowly lose voltage over time when left idle. If you haven’t had your car hooked up to a trickle charger or any other type of voltage maintainer, the voltage will have likely dropped below the amount necessary to start the car. Jump starting your vehicle may solve the problem. After the jump start, let your vehicle run for 5 – 10 minutes to recharge the battery. Then, switch it off and attempt to restart it. If your car won’t restart, there could be a problem with the battery or your vehicle’s electrical system. This issue can leave you stranded if it’s not remedied.

Before you attempt to jump-start your vehicle, remove the battery cables and check that the battery terminals are clean and clear of debris and corrosion.

Ideally, the battery should have a full charge before the vehicle goes into storage. Further, the battery should be disconnected from the engine to prevent discharging. The charge should be checked every three months. The battery should be recharged if it drops under around 12.4 volts.

Check The Gas

It only takes one month for the gas in your tank to start breaking down. As the lighter components of gas evaporate and oxidate, gas loses its combustibility and becomes less effective. As it degrades, it forms a gummy residue that gets released into the fuel system– increasing the likelihood of a blockage occurring. Old fuel can cause an engine to misfire and stall.

Obviously, we don’t recommend sniffing gasoline, but gas that has started to break down will have a distinct sour smell that resembles the smell of varnish. One option is to siphon a small amount out of your fuel tank and check the color. Old gas will be darker than fresh gasoline, and you may even be able to see the gumminess that have started to form.

If your car has been sitting for three months or longer, it is recommended to drain the tank and fill it with fresh fuel. For a car that has been sitting for a month or two, it is recommended to top up the fuel tank with fresh gas and dilute the old gas before it passes through your vehicle’s fuel system.

Finally, if you find you just aren’t driving your car much and it’s likely to sit idle for 30 days or more, a fuel stabilizer should be added to the gas. This will prevent degradation for up to 12 months. It is the easiest way to avoid damage to your cars fuel system.

Inspect The Tires

A visual check of the tires should be performed to make sure they are in good condition, before attempting to drive the vehicle. Air pressure should be checked and adjusted to the manufacturer’s recommended psi. This can be found on a sticker that is usually located on the driver’s door jamb. You could also find the recommended psi for your tires in your owner’s manual.

Upon inspection, your tires may look normal. But, when you get behind the wheel to take your car for its first spin in months, instead of the familiar smooth ride you may feel a vibration through the steering wheel and hear an unfamiliar noise. This is caused by a flat spot in the tire– a problem for any car that sits idle for extended periods of time.

This occurs when a stationary tire has to bear the load of a vehicle for an extended period. As the weight of the vehicle presses down, the bottom of the tire spreads out on the ground. As time goes on, the rubber gets stiffer, leaving flat spots on the tire.

Generally speaking, as you drive the car and the tires get warm and regain flexibility, the flat spots will disappear. This usually takes around 15 minutes. In extreme winter temperatures, these flat spots can become permanent if a vehicle hasn’t moved for several months.

Tires can develop flat spots if your car sits for an extended amount of time. Check your tire pressure before starting your car again to make sure it is at the recommended psi.

Check For Rodents

When the weather cools off, rats and mice look for warmer shelter and can be disastrous for car owners as their engine bay doubles as this season’s hottest rodent hotel. After mice have made a car their new home, their sharp teeth can cause serious damage to engine hoses, plastic panels, and wiring.

Signs that your car may have a mouse problem include:

  • Droppings and an associated bad smell
  • Unfamiliar noises when you switch on the fan or heater, indicating the presence of a nest
  • Food scraps in unusual places
  • Check engine light on your dash, indicating wiring damage
  • Bite marks on hoses and wires

Getting mice out of your car can be a time-consuming job. Not only will you have to find and remove their nest, but you’ll also have to clean and disinfect the area around the nest, and more than likely repair any damage they caused. There are many methods to prevent mice from moving back in such as spraying peppermint oil or putting out moth balls. Forget the ultrasonic sound repellants though–they won’t do anything besides put a hole in your wallet.

How Often Should You Start Your Car

Leaving a car unused for three months—or even three weeks—is not ideal. If possible, start your vehicle a couple of times per month when it is not being used. It’s best to not only start the vehicle, but to also drive it for about ten miles before putting it back in storage.

Starting the vehicle without taking it out for a quick spin will warm up the engine, but nothing else. It could also drain the vehicle’s battery, which will make it harder to start next time.

On the other hand, starting the car and driving it for 10 miles will fully warm up other parts of the vehicle, including the transmission, brakes, and suspension. Driving this short distance will also give your vehicle’s battery a chance to recharge, so it’s easier to start in the future.

Consider asking a close friend or relative to help.  Maybe they can take your car out once in a while when they go out to dinner or to run chores.

How to Prepare For Not Driving Your Car For A Month

If you plan on leaving a car unused for 3 months, there are certain steps you can take to keep it in good condition during this period of inactivity. Here’s what to do:

  • Use a car cover. You should always cover a vehicle that is not being used—even if you are storing it indoors. A car cover can protect your vehicle from long-term storage hazards, such as bad weather and animals.
  • Wash it. Be sure to thoroughly wash your vehicle before putting it in storage. Leaving water stains or other debris on your vehicle for a long period of time can lead to paint damage.
  • Get an oil change. An oil change will remove the dirty oil, which contains contaminants that could damage your engine while the vehicle isn’t being used.
  • Fill your gas tank. If the gas tank is empty or even half full, moisture will start to accumulate if the vehicle is not being used. To prevent this problem, fill the gas tank prior to putting your vehicle in storage.
  • Place the vehicle on jack stands. If you plan on not driving your car for a month or more, it’s best to take the wheels off and prop the vehicle up on jack stands. This requires additional work, but it will prevent flat spots and other forms of tire damage.
  • Don’t use the parking brake. Rust can form in the braking system if the vehicle is left in storage for a long period of time. If the parking brake is applied, this rust can cause the brake pads to fuse together with the rotor. That’s why it’s best not to use the parking brake before leaving your vehicle for a month or longer.

Following these tips can help preserve the life of your vehicle while it’s not being used.

What to Do If Your Car Takes A Long Time to Start After Sitting

Found a potential problem? Is your car taking a long time to start? Or unsure about any of these steps? The next step is to get a professional to inspect your vehicle and advise you of your options. Car repairs can be expensive, but giving your vehicle a thorough check-over before hitting the road will save you money in the long run.

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