1993 GMC Safari Owner's Manual - Page 219

If theoverheatwarningcontinues,there'sonemorethingyoucantry. can add the propercoolant mix directly to the radiator,butbesurethe cooling system is cool beforeyou do it. You 4 - Steam scalding and liquids a cooling fromhot system blow can out andburnyoubadly.Theyareunderpressure,and if you turn the radiatorpressure cap-even alittle-they cancomeoutat high speed.Never turn thepressurecapwhenthecoolingsystem, includingtheradiatorpressurecap, is hot.Wait forthecooling systemandradiatorpressurecap to cool if youeverhave to turn thepressurecap. I PO425 5-1 3