Engine Cooling problem
1999 Other GMC Models 6 cyl Front Wheel Drive Automatic 100000 miles
my car starts to over heat then it goes down. And is ok. There is antifreeze in the overflow but i'm not sure how much is in the radiator. So I bought some of the prestone 50/50 and wanted to know if I should add some to the radiator. Female and not sure what to do. Please help. Used to have problems with it always going past the halfway mark never really overheated but if i'm sitting in line or at a redlight it goes over the mark then back down. Why?