I just bought a used 2003 Cadillac DTS last friday (day b4 my birthday) 96,000 mi but the car runs great and everything works great and has proper services recorded. Today I saw the Check Coolant level words come across the display. So when I got home after car cooled off for a while I opened hood and did notice that the coolant was kinda low in resivor... So I try to open the coolant resivoir and I cant... So I read manual. The Manual states "turn counter-clockwise until stops, then pushdown and continue turning and remove".... But when I try it after turning first time pushing down doesnt help and it doesnt turn counterclock wise anymore.. I cant open the thing! anyone know what to do? I mean the car isant going to overheat or runout of coolant soon but still I like treating the thing right.