I have a 1999 Grand Prix GT, recently i've been having the low coolant light come on and turn off after a few minutes of driving so I didn't think much about it, checked the coolant it was a little low so i filled it up. Now today i went to start it and the light is back on followed by the SES light. Also the car runs really rough and is now spewing white smoke from the exhaust/somewhat from the engine. I'm thinking it might be the LIM gasket or a head gasket but i'd like to know what you guys think.