Long-term storage, in my opinion, is anything over a month. In 30 days, lots of things can start going wrong if you don't store a car right. Modern cars have their own problems since they can run a healthy battery down in less than a week sometimes with all the memory functions that have to keep going if you don't disconnect the battery. During winter storage, or any period of storage, it can take a toll on your vehicle unless you take some precautions to protect it while it sleeps. You can protect your vehicle from rust, animals and other storage headaches with just a little extra work. Here are some storage tips:

 

• Get it out of the elements! No amount of precautions will protect a car that is stored outside where the sun, rain, or snow will beat on it day in and day out.
• If storing it for the winter, make sure it is in storage before the first snow fall. Driving it on roads that have been sanded or salted just before placing them into storage can cause them to rust.
• Purchase a breathable cloth car cover. (Plastic covers will trap condensation and provide a fertile breeding ground for rust.)
• Give your car a bath and good coat of wax including chrome trim before storage.
• Make sure you get the under body of the car as clean as possible as well, especially the wheel well areas. The dirt will hold moisture and will combine with air and cause the iron and steel parts of your car to rust and rot.
• Clean the interior using an appropriate treatment. For example: vinyl cleaning methods, carpet shampooing (must be completely dry before storage to prevent moisture problems), chrome detailing waxing, glass cleaning, apply vinyl dressing to weather-stripping.
• To inhibit rust in the engine area, use a lubricant spray such as WD40 to coat all exposed metal surfaces. The volatile carrier in the WD40 will soon evaporate leaving a protective film on the hose clamps, coils, carb bodies etc. 'Wax-oyl' is also good, but you'll want to hose it off at a 'car wash' in the Spring.
• Fresh fluids at this point are a good idea. Oil and filter, anti-freeze, power steering fluid, transmission fluid and brake fluid should all be changed right before storage. A week or two before storage is OK except the oil, make that as fresh as possible. Dirty oil is contaminated with acids and water that can cause premature bearing failure and rust inside the engine. Freezing temperatures naturally dictate that anti-freeze be used. But even if it's not freezing, put it in. Many of the newer 'coolants' have excellent corrosion inhibitors that will help protect and lubricate your cooling system. A 50/50 anti-freeze/water mix is fine. Again make sure to run the car so it's mixed throughout the entire system. Lubricate all chassis fittings, door locks, hinges and latches.
• Fill the gas tank before storing with fresh quality fuel. If you drive your car so little that last years gas is still mostly in the tank, then siphon it off and use it in the lawn mower or dispose of properly! Fresh gas will last a full year if kept at a fairly stable temperature below 80 degrees. This will reduce the amount of water that can be absorbed by the gasoline and it also slows the rate at which it turns to varnish. Use a fuel additive. Make sure it's well mixed and run the car for a while to make sure it's in the entire fuel system.
• Remove important papers from the car/glove box. Try to leave the HVAC (heating, ventilating, and air conditioning) system in OFF mode.
• Give the car a good run and get it fully warmed up right before storage.
• Store convertibles with the top up. Convertible tops can actually shrink if they are left in the down position for an extended period of time.
• Leave windows cracked just a little to let some air circulate and let window seals relax so they seal better in the spring.
• Tires can be slightly over inflated to prevent flat spots.
• Do not apply emergency brake.
• It is better to let a car sit for months than to run it once a week for a few minutes. The reason is that you can't get the engine and other drive train parts warmed up enough to do any good and you will create condensation in the crankcase and exhausts that will help kill your car.