ide say you both fucked up. if the rad was leaking, it would have been apparent from when u started it earlier. did he not even pop the hood and look around? i mean, if thats case, u could have sold the guy a sled with no motor and he wouldnt have known the difference. then again, you probably should have inspected things closer and made sure it was in good running shape when he showed up. Ultimately, its the buyers responsibility to check that out.if u offer the guy money, and he says no, then revoke the offer and tell him to go shove the sled up his ass.