drain out
verb1
To empty (something) completely of liquids; to drain completely.
- Anti-freeze has not been found necessary, even in the most severe conditions, since the water is drained out if a locomotive spends any appreciable time out of service and in normal working conditions the coolant is always warm.1962 October, M. J. Wilson, “Three years of dieselisation at Devons Road depot”, in Modern Railways, page 264:
2
To be emptied of liquid; to be drained completely.