Oops, I meant 48*F! At that point my freeze up switch cuts out and cycles the AC pump off and I hardle notice my engine idle slowing when it kicks on. Dash vent temps are at 55*F to 57*F at idle and down to 48*F driving on highway! Believe me, I couldn't be more pleased! New Compressor as well. 4 Seasons makes a replacement for the GM R4 for a reasonable price and it works great with Envirosafe 12.