At 02:31 PM 4/9/2001, Joel Walker wrote:
> > Has anyone tried a correctly engineered propylene glycol coolant?
>The Evans system (no water=no corrosion) sounds very promising.  Check
>it out at: http://www.evanscooling.com/
>
>kinda odd to see the claims that they are making for prop. glycol ....
>what i've heard (and read on the backs of the containers) is that p.
>glycol is NOT as efficient as the ethylene glycol ... that is, a
>e.glycol mix goes to lower temps in winter and higher temps in summer
>(than the p.glycol mix). this sounds like the same old Sierra p.glycol
>mix of a few years ago. the package kinda looks like it, too.

Ethylene glycol freezing point -12.7C -- Propylene glycol f.p. -60C -- you
have to use more pg than eg in an aqueous mix because it doesn't depress
the freezing point as much; but eg reaches a minimum and starts rising
again while pg either doesn't rise at all or else not nearly as much.

Per info on the site, thermal capacity is similar to 50/50 eg mix (caveat
-- numbers given in xx/mole -- I'm assuming that a mole of mix is similar
amount to a mole of pg).

Dow makes the stuff, here's their data site on both -- they have a bunch of
pdf data, haven't looked at it yet.

http://www.dow.com/dog/apps/apps16.htm

david

>only thing i saw with p.glycol was that it wasn't poisonous to animals
>and people ... the e.glycol is definitely poisonous.  :(
>
>joel

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"