Just about to change the wife's antifreeze (well, the stuff in her car at any rate!) but it uses this tricky new "OAT" stuff. I only seem to be able to get it ready-mixed 50:50 with a claim that it protects down to -34 degrees C and a warning not to dilute it. Whilst that degree of protection would be handy if I lived in Moscow, I don't! So the question is, can I dilute it further, or do other bad things happen? Also, will those little antifreeze testers (the pipettes with the floating balls in them) work with this stuff or only with glycol antifreeze?