If it stays below freezing for extended periods of time, then corrosion protection is unnecessary. Rust does not form below freezing. Air is the safest IMO.
With all due respect I couldn't disagree more. Even dry winter air can contain 50% humidity or more. Water take on 3 states, liquid, gas and solid. Even at 40% humidity that gas that enters anything can and will become a liquid and a solid. Not enough to split cast Steel, Iron or Aluminum but enough to oxidize anything containing Iron. We had 2500 GPM cooling pumps in the Steel Plant. Usually 1 electric and 1 steam pump on back up idling. If a pump had to come out of service for any period of time other than PM that pump was isolated and 40 gallon drums of glycol was fed into it as to not let the metallic components oxidize. The pumphouses were heated to above freezing but as I said earlier oxidization will happen at below freezing temps.
I have been using plumbers anti freeze in my outboards and leaving them full of the -50F stuff for 9 years now. It was often left outdoors with the transom not 60 feet facing south towards old mean, cold, windy, and I mean 100KPH windy Lake Erie. I have never had an issue and after reading this thread consider myself lucky. I would never leave a anything that can oxidize empty. So what should I use? Regular automotive anti-freeze is what I'm thinking.
As far as recovering anything from a corporation I thought right out of the gate "good luck, you'll need it". They have more lawyers than most any Joe does but, and a big but. They don't throw around money for legal fees often. Here in Ontario the Joe consumer, related to plumber Joe, has one advantage. Our small claims courts in Ontario will award plaintiffs up to $10,000.00 CDN plus filing fees (80 bucks). Corporation Lawyers will meet with plaintiff's if they know that Joe plaintiff may have a case because he has evidence, no matter how remedial, and settle out of court after you sign a non disclosure. They aren't going to pay a company Lawyer many hours of billing fees when they don't have to. For 4 grand loss I would be filing in Small Claims tout suite. Don't most US States and Provinces here have a 5 grand Small Claims limit, that's less than the $4000.00 you are out. Show your findings to a Small Claims Justice and you may have a chance, they are most often fairly logical and around here don't like big companies bullying Joe Plaintiff. Here in Ontario unlike Superior Court a plaintiff need only prove beyond a preponderance of the evidence, not beyond a reasonable doubt. Watching Small Claims cases at our local courthouse can be entertaining on a cold winters day.
edit: I read back and yes you are a fellow Canuck, where? Don't be our typical "oh well, can't do much" nice apathetic Canadian. Be like a Pit Bull with a bone and don't let it go. I have dual citizenship and can be relentless when I think I have been scr$@d over, maybe my American 1/2 ? I once kept track of phone conversations with Hewlett Packard trying to get them to replace a bad Laptop. 38 hours of talking and or being kept on hold and 6 months of dealing with them. I stayed on hold once for 4 straight hours, every 20 minutes some service rep would ask "you still there Sir?" Yep and will be for as long as you tap out and send me a new Laptop. The $399.99 Laptop was of course no longer available and I got one that was 600 bucks retail, maybe 50 to them but they paid customer service reps more than 38 hours for them to save 60 bucks. I've sued the County and won when yellow traffic paint got all over my black car. They blinked, I won. Lot's of time when retired.
