Normal is 192 to 195 as long as it has the stock T-stat in it.The car has heat now but the temp. gauge only registers to about 180.
Explain "no heat"; the fan ran and was blowing cold air or the fan wouldn't run at all.when she start driving again she had no heat.
Also, which year and model Grand Prix? Manual A/C or Auto A/C (1998-2000)?