A flexible universal bladder tool is disclosed to be coupled between a source of “smoke” and a fluid system to be tested for leaks, such as that found in the automotive industry. The bladder tool is an inflatable bladder that surrounds a flexible smoke delivery tube which communicates with the source of smoke and a fluid duct of the system under test. By virtue of the flexible nature of the smoke delivery tube, the inflatable bladder is adapted to be bent around any of a variety of curved fluid ducts. The flexible smoke delivery tube is detachable from the tool so that the tube can be quickly replaced with a different tube having a different length. The inflatable bladder is filled with fluid (e.g., air) to expand into sealing engagement with the fluid duet, and the system under test is pressurized with smoke supplied thereto by way of the flexible smoke deliver tube.