The cooling system of your car or truck is a critical component. If you have a leak in your radiator, your vehicle won't cool properly, and could overheat, causing lots of damage to the engine. Problem is, if you radiator does have a leak, you just have two options: replace it or take it to a repair shop. But to save some money if you decide to repair it, you want to find the leak so you can show it to the shop, saving you some costs in the long run.
Open the hood and start to look at the radiator. Sometimes, the coolant leaks are obvious, because you can see the coolant stains on the surface. If you can find stains, that should point you in the right direction.
Search the radiator for any leaks using the flashlight. Radiators leak usually from the sides of the tank, or on the front from damage caused by rocks. Any stains in this area are good signs of a leak.
Shine the black light flashlight on the radiator, looking for leaks. Some brands of coolants will shine brightly under a black light, which will help you find the leak.
Using the shop rag, clean the area surrounding the leaks that you've found.
Mark the area around the leak using a paint marker. By doing this, you can show the repair shop where the leaks are, and save some costs in the process.
