50-50 mix of coolant.
If you're just going to let it sit, pull the batteries and put them
indoors where they won't freeze.
Go buy 3 gallons of RV antifreeze. Drain water tank. Pour it in
through the top of the tank.
Run faucet until it comes out pink.
Winterized.

Me? I drive my Vanagons year round. I've found that the diesel REALLY
likes the block heater. The gasser? Probably wouldn't make a whole
lot of difference. The diesel tends to crack the coolant header tank
when it gets really cold.  I've split 2 of them. Both when the temps
were in the -20 deg F range.

The important thing is the 50-50 mix of coolant. I use a hydrometer
to check it about mid November. Adjust as necessary.

Jeep? Read the owner's manual regarding cold weather operation. I'd
suggest a 5W40 synthetic motor oil and don't touch the throttle when
trying to start it. Really cold temps and it will immediately flood.
(Ask me how I learned this...) Block heater is a good idea as well.
Cheap insurance.

Jim

On Sep 18, 2008, at 6:28 PM, Mike Elliott wrote:

> MW will probably sit in sub-freezing temps for several months with
> maintenance chargers hooked up to the starter and house batteries.
> I could
> use a "Dummy's Guide to Winterizing Your Vanagon" here.
>
> ==========================
>
> Note 1. As a side note: My son's Jeep Cherokee -- anyone here have any
> Handy Tips for dealing with these colder conditions? P-mail me as
> that is
> extremely NVC.)