A portable leak detector kit uses a stethoscope-like arrangement including a flexible and shape adjustable tube with several different interchangeable heads mountable at a distal end of the tube for picking up leak sounds of equipment or machinery. A first sound receiving head has a spheroidal shape with an external wire netting while a second head has a surface of spaced apart bumps and apertures and is made of a flexible material enabling it to be wrapped around a pipe, and a plurality of flexible third heads of different sizes enabling them to be selectively clamped around one of a range of NPS size pipes and each having a first open channel in an inside surface. Sound conducting paths join exterior surfaces of the heads to a neck which is ultimately connected through the tube to an ear piece used for listening to the leak sounds.