Your car needs you even when you don’t need it. Maintenance issues arise when cars sit unused or barely used for weeks or months at a time. As a rule of thumb, you should at least take one 20-minute drive every two weeks, but even then a car could suffer from underuse. If a car is underused for an extended period, here’s how to make sure it won’t suffer badly…

Attach the battery to a battery maintainer. When a car sits unused, its battery will slowly go dead. If your car was built within the past 10 years, that could happen in as little as two weeks—modern cars are packed full of electronics that drain power even when the car sits idle. Driving only on short trips can make things worse—each start taxes the battery…and drives lasting less than 20 to 30 minutes don’t give the alternator sufficient time to recharge it. A battery maintainer plugs into an electrical outlet and keeps the battery charged without overcharging it. Examples: Diehard Battery Charger/Maintainer, $26…NOCO Genius 6V/12V 1.1 Amp Battery Charger and Maintainer, $40.

Keep tires inflated. When cars are driven regularly, drivers tend to notice low tire pressure and add air. Most modern cars even have a dashboard light that warns of low tire pressure. But when a car sits for an extended period, pressure can become dangerously low. If pressure falls to around 10 psi or below—way below the proper psi, which can be found inside the car’s driver door—driving even a short distance to a gas station for air could permanently damage the tires. That damage could cause an accident if the tire later fails at high speed. Instead, buy an air compressor so you can reinflate tires at home. Example: Rugged Geek RG1000 Safety Plus Gen2 features a portable jump starter and portable air compressor, $140. 

Also: If the car is sitting unused for multiple months, occasionally drive or roll it a foot or so to prevent the tires from developing flat spots, which could make the ride less smooth in the future.

Add fuel stabilizer to the fuel tank if the car will sit for six months or longer. Fuel degrades over time and after around half a year can gum up carburetors and fuel injectors, causing hesitation and stalls. Fuel stabilizer keeps gas fresh for a year or two.
Example: Sta-Bil Storage Fuel Stabilizer, $4 for an eight-ounce bottle sufficient to treat up to 20 gallons of fuel.

Change your oil based on the calendar. Car owners are used to getting their oil changed each time they travel a certain number of miles—as much as 5,000—but check your owner’s manual. It likely recommends changing the oil every six or 12 months even if that mileage hasn’t been reached. 

Thoroughly clean the car’s interior. Rodents often are emboldened to enter cars that sit unused for extended stretches—especially if they can smell food inside. Carefully vacuum out all crumbs, and remove food packaging. Also, rodents can get under the hood and chew wires and hoses. Placing mousetraps around the garage can reduce the odds of this if the traps are monitored and reset as needed. 

Leave the parking brake disengaged. Parking brakes sometimes fail to release after they’ve been engaged for months. Instead, park on level ground, and of course, leave the transmission in park…or in gear if the car has a manual transmission. Use wheel chocks, too, if there is no perfectly level parking spot available. 

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