Abstract: An improved radiator vent valve and syphon tube assembly is provided, the vent valve including a valve body and a threaded valve nipple adapted to engage a wall of a radiator. The nipple defines a passage communicating between the interior of the radiator and the interior of the valve body and the syphon tube drains condensate from the interior of the valve body into the radiator. The syphon tube includes a tubular portion adapted to be inserted into the passage defined by the nipple, the tubular portion including resilient tabs about its outer surface which permit insertion of the tubular portion into the nipple and after insertion, yieldably engage an inner surface of the nipple. The syphon tube also includes a generally trough-shaped portion coplanar with the tubular portion and another trough-shaped portion oriented to direct the flow of condensate downward when the tubular portion is horizontal. The three portions of the syphon tube provide a substantially continuous flow path.