A car can sit idle for a rather long period of time without any major damage taking place. There are, however, several items you should address before attempting to revive the car; otherwise starting the car could seriously damage some of the components. Most of the issues are common sense, but addressing them can be slightly challenging. Your first task is to get the car started; actually making it road-ready will require additional measures.
Locate the drain cock on the bottom of the gas tank. Place a large drain pan under the plug, and slowly remove the plug. You can turn the plug with a crescent wrench on most cars. If your tank has no drain cock, remove the clamp from the fuel line and pull it free from the tank. Allow the gas tank to drain completely before adding fresh gasoline.
Change out the fuel filter. Location and method of removal varies by car, but these are not normally complicated, hard to reach or expensive to replace. On many vehicles you must only remove two small clamps, one at each end of the filter. Grip the clamp tightly with a pair of pliers and work it farther up the fuel line until you can remove the filter. Repeat this on the other side, then install the new filter. Pay attention to which direction the fuel should flow through the filter.
Charge or replace the battery. After sitting idle for a year, the battery will most certainly be dead and may no longer be capable of holding a charge. In most instances it will be better to replace a battery that has been idle for such a long period of time. Use an open-end wrench to loosen the bolts on the battery cables. Very carefully pry off the cables. If there is any corrosion on the cable terminals, sand them to get a smooth surface. Place the new battery in position and reattach the cables.
Remove and replace the spark plugs, using a socket wrench with deep sockets. Replace one spark plug at a time. Remove the plug wire, then place the socket over the plug to pull it out. Insert the new plug and reattach the plug wire before moving on to the next plug. This will prevent you from crossing the plug wires and throwing off the timing of the engine. Changing the plug wires can normally wait until you are certain the car is repairable.
Check all fluid levels. While several of these, such as power steering fluid and brake fluid, will not be necessary for start-up, definitely make sure the coolant system is filled to the proper level.
