The present invention provides a delivery system for providing an atomized treatment agent like a cleaner or lubricant to a specific internal location of a closed mechanical system like an internal combustion engine. The atomized treatment agent is delivered via a flexible, non-rigid conduit to the desired internal location of the engine between, e.g., the ID/OD coupling joint between the air inlet hose and the throttle body. A special conduit support guide, the end of which is inserted through the ID/OD coupling joint, provides the proper geometry for gently configuring the conduit to enter the ID/OD coupling joint without crimping and controlling the directional approach and distance of the conduit free end inside the engine.