Q: blown engine

Unless there is a contributing factor in the failure, such as a deteriorated hose or hose clamp failure, the person who improperly connected the radiator hose is the only person responsible for repairing or replacing the engine. They may do it willingly or, if not, you can potentially recover via a small claims court action. Note that if the head gasket is blown, the head and/or the block could be warped which would necessitate re-surfacing of those components. Also, the cylinder walls and valve guides can be damaged if there is severe overheating. So, it is not just a simple matter of applying a new gasket. The engine cooling thermostat is probably ruined as well. Be sure not to re-use that if you re-build the engine. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine overheating diagnostic and the responding certified mechanic will let you know of the required repairs and the cost. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.