Heater core or not?
 

Hello,
I have an 01 grand prix 3.1L. Automatic.106k. I have antifreeze entering the insde of the vehicle under the dash about in the middle. Both sides of the front floor boards are wet with the stuff. I recently changed the heater core for this exact same problem. We noticed no leaks or antifreeze smells for about 1 month. But today it is back. Any ideas? Is the replacement heater core bad from O'reilys, or is something causing my heater cores to fail?
Any ideas and help will be greatly appreciated.
Thanks,
Fuzzydog1

RE: Heater core or not?
 

A new twist.
Yestrday when I drained the coolant I noticed a white powdery substance on any surface that had coolant laying on it and then dried. Any ideas on what this white substance could be?

01"Temp readings
 

Does anyone have an '01 that can tell me where the temp gage normally should run at? Mine is usually around 185 but also goes above 210 and eventually works its way back down. I changed the coolant, heater core, radiator cap and the thermostat on this go around of changing out the heater core(2nd one).thx, fuzzy

RE: 01"Temp readings
 

Found out yesterday that the temp reading goes up to 220 before the fans kick on.