Q: Would it be alright to put dish detergent in a radiator to find a leak by having the bubbles come out?
A: This is not recommended. Commonly two methods are used: an ultraviolet light detection system or a pressure tester. An ultraviolet (UV) light system uses a dye that is put into the cooling system. Once the coolant has circulated, then a UV light is used to locate the leak. The leak will glow under the UV light. Another method to use is a cooling system pressure tester. A pressure tester adds pressure to the cooling system pushing out the coolant at the leak.