I have 1998 ponitac grand prix gt 3800, my temperature gauge just started fluctuating on fri, so my son checked the radiater and it was low, where is the coolant going, I put fluid in the reservoir and radiater and the fluid in the reservoir is empty now, I don't see any visible leaks under my car, but it feels hotter then normal.
Please help

Check the oil level. Coolant may be getting into the oil, due to a leaking lower intake manifold gasket or blown head gasket. Is the exhaust white?