Oh, and the oil won’t build up “junk” in it.
However, if the car wasn’t driven for at least half an hour straight in the week before it was stored, it probably had had water oxidizing its motor oil for quite a while.
I would change it out if you decide to restore it to active service. If you’re just going to drive it for an hour or two from the garage to your buddy’s shop and then to a recycler, don’t bother.
If you plan on selling it for any real money, check the dipstick. If it is even slightly blackened, change it out, even if you put in Wal-Mart store-brand oil. Guys like me will sniff the oil and tranny fluid (and do a blotter test on both) before buying.
I’ll reiterate that my OEM Honda battery was perfectly fine after two years in my car – it was disconnected the whole time. However my 12V lawn mower battery (also a Honda now that I think about it!) did die last year when I wasn’t home to cut my own lawn. I hadn’t bothered to disconnect it.
So to go a little off topic: Is there any relation there to my two Honda batteries, one connected and the other not? Honda hasn’t made lawn tractors in years, and it was an original battery, so it was older than the car battery that did survive.
Rhythmdvl, have you considered that you could borrow a similar-sized battery from another vehicle? If it’s not freezing cold, you shouldn’t have to worry too much about cranking amps – just be reasonable and don’t try to start an old Olds 454 with a borrowed battery from a Chevy Aveo.
Disconnecting it is the key.
A lead acid battery will last for quite some time if it is not connected to anything. Leave it connected to something with even a small current draw and it will go dead fairly quickly. Most cars will kill a battery in a couple of months if it is left connected. There’s a slight drain on the battery for your engine’s computer so that it doesn’t lose all of its settings. Your radio also has a memory in it, which draws a bit of power from the battery so you don’t lose your station presets.
I’m kinda surprised that the lawn mower battery died. I would expect the circuit on a lawn mower to completely disconnect the battery when you switch it off.