How can you diagnose a cooling system leak without disassembling the engine?

How can you diagnose a cooling system leak without disassembling the engine?

• A. Rely on coolant smell alone to locate a leak.
• B. Shake the radiator and listen for leaks.
• C. Use UV dye and a blacklight to reveal leaks.
• D. Check the overflow reservoir for leaks.

Answer: (C)

Using a UV-reactive dye in the cooling system is a tracer method that makes leaks visible without taking the engine apart. You add the dye to the coolant and run the engine until the coolant circulates. When you shine a UV light in a dark area, any place where coolant escapes will glow because the dye traces through the system. This lets you pinpoint leaks anywhere—hoses, radiator seams, the water pump, or the heater core—even if the leak is very small or hidden. It’s more reliable than relying on smell or listening for trickles, and it goes beyond what you can learn from simply checking the overflow bottle. After the repair, you may flush the system if your dye requires it.

Using a UV-reactive dye in the cooling system is a tracer method that makes leaks visible without taking the engine apart. You add the dye to the coolant and run the engine until the coolant circulates. When you shine a UV light in a dark area, any place where coolant escapes will glow because the dye traces through the system. This lets you pinpoint leaks anywhere—hoses, radiator seams, the water pump, or the heater core—even if the leak is very small or hidden. It’s more reliable than relying on smell or listening for trickles, and it goes beyond what you can learn from simply checking the overflow bottle. After the repair, you may flush the system if your dye requires it.