Well the last few weeks my car would ping like mad after runing it hard for a min or so....and it was runing realy hot....so i got pissed and flushed the coolant...first time in a long time i have done this...then i swap in a 180* t-stat and now it is like it used to be years ago it just won't get hot...(stock Guage) i was even running it hard in 99* heat with the A/C and i heard one little ping i think but the temp guage wont go above R anymore before i was close to pegging it.....sorry i am just happy that this fixed my problem.