This is a short demonstration showing how I made the diagnosis and completed a repair of an occult coolant leak in a 2000 Chev Suburban. I pressurized the system and found the leak by carefully searching for the source of coolant loss. Pressure testing is a convenient way to find small leaks where no evident coolant loss is visible on general inspection.
Cooling system repairs can be dangerous, because superheated liquids under pressure will instantly boil and expand when pressure is relieved, causing explosion and severe burns that can be life threatening. Any misadventure you encounter if you decide to accept the risk of DIY repair is your responsibility.