-> Propylene glycol (the original brand was Sierra, though I see that
-> Prestone is selling a similar product now) is the chief component of
-> the low toxicity anti-freezes (i.e., it won't kill your cat or dog if
-> it licks the puddle under your car)
Ethylene glycol, with additives and packaged as coolant, is incredibly
sour and tastes *terrible*. No animal is going to take more than a
couple of licks. I drank some of the stuff once to prove it's not as
big a deal as some people claim. EG *is* toxic; it'll wreck your
innards if you drink enough of it, but you'd be hard up to actually
swallow that much.
Propylene glycol, marketed as "safe" coolant, is still toxic; roughly
50% as much as ethylene glycol. If you can manage to choke enough of it
down it will still kill you. The whole safety thing is a marketing
*Poly*propylene glycol is the stuff that's safe; it's used in ice cream
and as a sweetener in some foods. Lots of people confuse it with PG,
but it's not used in automotive coolants as far as I know.
Lots of people claim PG tastes sweet and animals and children will
drink it; I taste tested several brands, and that's absolutely not so.