The Trupow hand rotary drum pump can't be used for gasoline and drinking water!
Suitable for water based solutions of acids, alkalis and salts, some organic solvents, water, all petroleum products. Most organic acids, solvents, waxes, plating solution, detergents & water-soluble inorganic chemicals.
If you don't use it too often all the fluid comes out of the pump. You need to "prime it", pour some coolant from the top spout into the pump assembly, then start pumping coolant.