My carrier home unit fan blade started screeching yesterday. Hit the shaft with some WD ad this is all I had. Lasted 1 day. Now hear again. Don't want to burn up. Should I put some 3 and 1 on it or is there someplace for oil or is it going out?

fan blade started screeching

Since you said fan blade, I suggest that the actual blade part has worked loose from the mounting collar.

Suggest that you remove the fan from the motor, then peen over the clenching. In other words, put the fan on a flat surface, mounting collar down and tap around the center hole.