Long term storage preparation
If storing a vehicle for the winter or longer, a few precautionary steps can make a difference.
 Basic procedures for storing a car for a significant length of time
- Change the oil before storing.
- If possible, keep tires off the ground. Major advantages are not to cause flat spots on the tires, another being less area for rodents to grab and climb upon. Use jack stands to accomplish this.
- Add fuel stabilizer.
- Place cardboard or newspaper under the car to highlight any leaks that may develop while in storage.
- Clean and treat interior to prevent cracking.
- Inspect entire vehicle for issues that can be corrected during winter months.
- When running a vehicle during storage time, be sure to bring it up to full operating temperature, and keep it there for a while. This will prevent internal condensation in the engine and oil.
- For long term storage, one of the most important things that you can do is to remove the spark plugs and squirt some light oil into the cylinders then rotate the engine a couple turns, then screw the plugs back in finger tight. This will keep your pistons and rings from seizing. When you then take it out of storage you can remove the plugs and spin the engine over with the starter to remove most of the oil. Then re-install the plugs and your ready to start your engine. Or you could use a product known as fogging oil. It is in a spray can and you spray it down the intake while running at a high idle then you finally allow the engine to choke down and die. This will coat everything in the upper cylinders with a light lubricant.
- You can place a vehicle on four jackstands that are sitting in oil drain pans, pour a small amount of used oil in the pans so that the bottom is completely covered. This will prevent rodents from entering your vehicle because they won't cross the oil.
It's obviously always better to store a vehicle in a climate-controlled environment. This isn't always possible, so if there's going to be a lot of heat or sunshine on the vehicle, protect the dash with a sun screen and a UV protectant. Cover the upholstery w/sheets to keep the sun off it. A breathable fabric car cover can provide a good amount of protection both indoors and outdoors if tied down properly. Avoid cheap covers- they can damage the finish.
Pressure can build up if the vehicle is sealed with the windows closed, etc. If there is a vent, open it a bit to allow the pressure to equalize, or crack a window a bit, unless this is outdoors.
Check anti-freeze for proper freeze protection. Tools are available from cheap to expensive for testing the effectiveness of coolant for freeze and boil over protection. An easy to use and accurate method is to use test strips. They are simply dipped into a sample of the coolant and the color change will indicate the coolant condition.
Disconnect the battery cable and keep the battery on a battery storage tender or regulated trickle charger. If the vehicle is computer controlled, at start up the engine may run rough until the computer relearns and resets itself.
A neat tool that can test both battery acid and coolant is the Extech Portable Refractometer.