Abstract: An engine block in combination with an oil drain tube for allowing oil from a turbocharger to drain back into the engine block includes a substantially cylindrical bore in the engine block into which a portion of the oil drain tube is press fit. The oil drain tube includes an insert portion which establishes a sliding fit with the drain-back bore, an interference fit portion, and an O-ring channel which is positioned between the insert portion and the interference fit portion. An O-ring seal is positioned in the channel and is sized so as to be placed in compressive contact against the inside diameter surface of the engine block bore. Although there is an interference fit between the interference fit portion and the bore, the compressive contact by the O-ring seal establishes a leak-free interface between the bore and the oil drain tube. This allows the oil drain tube to be turned or twisted within the bore without breaking or otherwise losing the leak-free interface.