A Pressure Tester (pump) or UV dye can be used to find what?

• A. Transmission leaks
• B. Oil leaks
• C. Cooling System Leaks
• D. Exhaust leaks

Answer: (C)

Testing the cooling system with a pressure tester and UV dye works because this system is designed to operate under pressure with coolant circulating through radiators, hoses, and the heater core. A pressure tester cements a known pressure in the circuit, so any weak spots—hoses, radiator seams, the heater core, or water pump seals—will leak coolant visibly. Using UV dye involves adding a fluorescent dye to the coolant; when you shine a UV light, the dye that escapes through leaks glows, making even tiny seepages easy to spot. These methods are specifically aimed at locating leaks in the cooling system, not in the transmission, engine oil, or exhaust, which require different diagnostic approaches.