Due to serious illness, we have to store son’s car outside for about 6 months. Do we need to do anything to the car?
I would put in some fuel stabilizer and hook up a trickle charger. Make sure you follow the directions on both packages.
Six months is no major problem for the car. Add fuel stabilizer. Either disconnect and remove the battery or put it on a trickle charger. Vacuum the car well and put a few mousetraps inside in case anything gets in there. Wash it (by hand or with a touch-free automatic wash) so that it at least starts out clean. Call his insurance agent to see if the liability and collision coverages should be cancelled.
On the other hand, if you could take it out for a good drive every two to three weeks, then that would work just as well.
Just be sure that you DON’T do what some people do, namely start the engine once a week and run the engine at idle speed for 10 minutes before shutting it off. That is the absolute worst thing that you can do for the engine, the exhaust system, and the battery.
Either do as Whitey advises and keep the car parked for the entire time, or do as lion9car recommends and start it up once every 2 or 3 weeks, take it out on the highway for at least 25 minutes, and then park it again for a few weeks. If you do the latter, just remember to refill the tank after a couple of these outings, as condensation builds up much more rapidly in a gas tank that is not full.
If it is not going to be driven for 6 months, and frankly I would not drive it just to drive it, you may be able to cancel the collision insurance. It will still be protected from other risks but since it is not driven, it can’t have a collision. Collision is the most expensive part of auto insurance.
I would remove the battery and store it away from the car with the trickle charger (battery tender)