1. If you are using a 55% antifreeze solution (-50̊F nominal protection) in PVC (plastic) hoses or pipes, remember that the burst point is actually only about -15̊F.
An antifreeze fluid that protects to -50̊F, means that a copper pipe filled with that product will burst at -50̊F.
However, the actual solution will start to form ice crystals at approximately +12̊F.
As the temperature drops, the solution continues to form more dense ice crystals and expands. As the solution expands, it puts pressure on the pipe; and at -50̊F the copper pipe will burst.
Because they are not as strong as copper, PVC hoses & pipes, thus protected, will burst at about -15̊F.
2. When winterizing your Engine, remember that adding antifreeze must be done with the engine totally warmed up and the thermostat OPEN.
A closed thermostat will not allow the antifreeze to enter the block or heads. This means the antifreeze will go through the manifolds and out the exhaust
, leaving the block and heads completely void of any antifreeze.
3. Vodka is mixture of water and ethanol. Pure 80 proof (40%) vodka will freeze at approximately -20F (-29C) - roughly equivalent 45% glycol.
You’d have to fill your water system with ONLY undiluted Vodka to achieve freeze protection.
In addition to propylene glycol, a good antifreeze will contain a number of additives (lubricants, PH stabilizers, & corrosion
, scale & algae inhibitors).
See also Chuck Husick on Antifreeze
(Techno-Talk, May 2006 from BoatUS Magazine)
Goto: Chuck Husick on BoatUScom
And numerous other Winterizing tips from BoatUS
Goto: BoatUS.com Winterization Tips