The invention relates to an adjustable-length connecting rod for a reciprocating piston engine, to a reciprocating piston engine, and to a vehicle, where an effective connecting rod length of the connecting rod can be changed, and the connecting rod has a hydraulic length adjustment device which has a hydraulic working chamber, a hydraulic duct, a valve recess with a valve recess longitudinal axis, and a valve device which is arranged in the valve recess and has a valve chamber, where the valve device is configured for opening and/or shutting of a hydraulic medium outflow from the hydraulic working chamber, and the hydraulic duct opens into the valve recess at an orifice opening in an inner wall section of the valve recess. The valve device has at least one closed outer wall section which lies opposite the orifice opening and surrounds the valve chamber of the valve device, where the outer wall section of closed configuration of the valve device configures a flow duct together with that inner wall section of the valve recess, where the flow duct is configured to divert hydraulic medium, which exits from the hydraulic duct with a first flow direction and enters into the valve recess, in a second flow direction which is different from the first flow direction before the entry into the valve chamber.