> John at Mazdatrix claims this is caused by a failed pressure
      > cap. Even in street cars. I am not so sure. It looks like
      > simple corrosion to me. In any event it would not hurt to
      > buy a pressure cap tester. Such a cheap device can be critical
      > to the cooling of your aircraft engine.
      >
      > A pre flight cold cooling system pressure check using compressed

air

      > would accomplish the same thing.
      >
      > Paul Lamar
      >
     If this pitting is caused by a failed pressure cap, how did it fail?
     Did not
     open with too high pressure or did not hold the pressure?
     What did cause the pitting - too much pressure/high flow velocity -
     local
     boiling/overheating/melting/vapor pockets imploding?

     IF this would be of serious concern it will be very interesting to
     see how
     those fair that will use Evans- 0 pressure coolant!
     If it doesn't boil at ambient P, with some pressure on it, it should
     work
     still better....
     Dave (Leonard), didn't you plan to switch to Evans?

     Thomas Jakits

Yes, I am swithching, but it is being installed this weekend.  I have
not flown with it yet.  Rusty and Ken Welters are using it now (maybe
others).  Of course, it will be a while before I know if it caused
pitting too  :-)

Dave Leonard

Well lets hope it will NEVER pit!!
The curiousity would be to test temp/pressure ratios this coolant can take
before forming local boiling.

Good luck with the turbo!

Thomas J.