Coolant caps

[Bernie Strub <bstrub@silverlink.net>]

While talking with a fellow Audinaut, whose passion is turbocharging, he
brought up the fact that there are various pressure ratings for the coolant
system cap (on the recovery reservoir).  He had heard that the ratings are
delineated by the caps being different colors.  Black, blue, red, ???  Does
anybody know what the color to pressure rating relationship is?  I wouldn't
begin to know where to find such esoteric info, but I'm sure someone here
has the information already gathered.  Thanks in advance!
>>>>>Bernie
QCUSA #1765
Member #47 NW Region AQC