Almost half of the radiators could be salvaged, and used for heat exchangers for new homes. If not, why not?

Every month thousands of cars and trucks are crushed in most metropolitan locations. Almost half of the radiators could be salvaged, and used for heat exchangers for new homes. If not, why not? On the North side of the house, a small fan could blow cool air into the house, pressurizing the house slightly. This would reduce dust and insect entry. Smaller amounts of cool air from near the floor would pass though the former water part of the radiator, slightly cooling the incoming air. The other advantage is fresh air for the house