A hydraulic joint for a cooling circuit of a motor unit, said joint being configured to define a hydraulic coupling condition between a first pipe and a second pipe, and comprising: a guide pipe configured to adopt a position for fixing said the first pipe, said coupling condition corresponding to said position for fixing the guide pipe and to a position for inserting an end portion of said second pipe in said guide pipe; the guide pipe comprising a first end portion and a second end portion which is opposite the first end portion; the second end portion of the guide pipe having a collar;- a sealing unit interposed between said end portion and said guide pipe, in said inserted position of the end portion; - a body for locking the second pipe to the first pipe; wherein the guide pipe is configured to allow adjustment, in the coupling condition, of a positioning or axial movement and an orientation or angular movement of the second pipe, by means of a translational movement of said second pipe along its axis and relative to said first pipe, and by means of a rotary movement of said second pipe about its axis and relative to said first pipe, respectively; and wherein the locking body is positioned between the second pipe and the guide pipe, by means of a locking movement, in an operating position in which the locking body prevents the disengagement of the end portion from said guide pipe; said locking body being configured to allow the end portion of the second pipe the possibility of positioning or axial movement and an orientation or angular movement of the second pipe in said locking operating position, characterised in that said locking body defines snap-on locking means and can be locked in a snap-on fashion in said operating position using said locking means; when the locking body adopts the operating position, the locking body is engaged with the collar in such a way as to be constrained at least axially relative to said guide pipe; the locking body forming an elastic gripper comprising two arms (71 and 72), which can be mutually locked using the locking means which are formed by the arms and in that way, the locking body can be easily locked in the operating position by means of a rotation of the two arms of the gripper on a plane at right angles to the axis of the second pipe. a guide pipe configured to adopt a position for fixing said the first pipe, said coupling condition corresponding to said position for fixing the guide pipe and to a position for inserting an end portion of said second pipe in said guide pipe; the guide pipe comprising a first end portion and a second end portion which is opposite the first end portion; the second end portion of the guide pipe having a collar;- a sealing unit interposed between said end portion and said guide pipe, in said inserted position of the end portion; - a body for locking the second pipe to the first pipe; - a body for locking the second pipe to the first pipe; wherein the guide pipe is configured to allow adjustment, in the coupling condition, of a positioning or axial movement and an orientation or angular movement of the second pipe, by means of a translational movement of said second pipe along its axis and relative to said first pipe, and by means of a rotary movement of said second pipe about its axis and relative to said first pipe, respectively; and wherein the locking body is positioned between the second pipe and the guide pipe, by means of a locking movement, in an operating position in which the locking body prevents the disengagement of the end portion from said guide pipe; said locking body being configured to allow the end portion of the second pipe the possibility of positioning or axial movement and an orientation or angular movement of the second pipe in said locking operating position, characterised in that said locking body defines snap-on locking means and can be locked in a snap-on fashion in said operating position using said locking means; when the locking body adopts the operating position, the locking body is engaged with the collar in such a way as to be constrained at least axially relative to said guide pipe; the locking body forming an elastic gripper comprising two arms (71 and 72), which can be mutually locked using the locking means which are formed by the arms and in that way, the locking body can be easily locked in the operating position by means of a rotation of the two arms of the gripper on a plane at right angles to the axis of the second pipe.