Year plus... tough call - Storage cost vs buy/sell....
I've left cars for a few years while overseas, This is what I do
1) Drain fuel as low as it will go. Squirt WD40 on fuel cap gasket and re-install.
2) Change oil and filter
3) Drain antifreeze. Squirt WD40 on radiator cap, re-install. (leave a couple gallons of 50/50 mix on the passenger seat floor so it will be ready when you re-activate)
4) Cover car and tires.
5) If possible, jack car to get tires off ground.
6) If you have access to the spark plus, remove them, squirt a few tablespoons of oil in each of the cylinders, re-install the plugs.
7) Steel wool in exhaust pipe, Heavy plastic bag over intake (use wire ties or electric tape to secure it)
8) Remove battery, (at least disconnect it)
10) spray WD 40 on all hinges locks, etc.
2001 Coachmen Mirada (Ford F53 6.8L V10) - Toad 2001 Civic
It won't do MACH 2, but I can get a sandwich and take a pee.