Coolant loss

How often do you have to add coolant? Twice a day? Every other month? For a real slow loss of coolant, the best approach is to add a small bottle of dark purple dye, then check a day or two later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. Be sure to check for the dye inside the tail pipe.

Auto parts stores will have the dye for the fluid being tested, and those that rent or borrow tools should have a black light.