Thanks IR, and thanks to everyone else for the suggestions. I'll put the Kleen Kanteen on the list of things to try, it's steel as opposed to aluminum so probably behaves differently. I also picked up 4 Wenger equivalents to the Sigg bottles fairly cheap on good ol' ebay, so I can sacrifice 1 or 2 without feeling too badly.

Put the polyethylene (Nalgene) quart bottle through a couple of freeze/thaw cycle, filled and capped before freezing (yes, the "wrong" way to do it). Bulges at its weakest point, the middle, when frozen as expected. Didn't split, but its ability to "give" most likely degrades with age, so I didn't expect to learn anything more by cycling it some more.

Just to recap: Ideally, I'd like a container that can just stay in a vehicle holding water year round and be heated in the winter to get some liquid out of it. Year round, in the glorious upper midwest, means one has to expect temps that can range from -25 deg. F to +100 deg. F. The "leave it in the vehicle" part means that "properly" filling and freezing water in any kind of container is not an option, it's going to be subjected to freeze/thaw cycles all on it's own. It could be, say, 20 deg. F overnight and 40 deg. F the next day. I really like IRs idea of keeping it under the hood, which means that liquid water will be available some percentage of the time, but this also would seem to make necessary the use of a metal container as plastic would melt; and residual engine heat is only going to keep it warm for so long, so were back to the freeze/thaw cycling again.

Soooo... Again. I'll be experimenting this winter (aluminum, steel, full, half-full, etc.). IR says this can be done and, dammit, he's never lied to me in the past! <img src="/images/graemlins/wink.gif" alt="" /> Thanks again to all.

-Meat