A few questions. Are there ever any water or antifreeze puddles under the car or in the cars floorboard. If so it is a hose , seal , gasket or heater core . Next if no fluid can be found anywhere it my be leaking under the intake manifold ther is a spider of cooling pipes and hoses under there , but it also could be burning it , that could mean a bad head gasket. As for a diagram there is so many pages in the dealer repair manual I can't post them all .