Carver took his car to Dorschel Motors to have work done on the engine. He specifically told the head mechanic to repair, not replace, the engine. Instead of repairing the engine, the head mechanic instructed the mechanic who worked on the car to replace the engine with a rebuilt motor. Carver did not know of this work until he was handed the bill. When Carver asked why his instructions were not followed, the head mechanic stated that replacing the engine was the most economical thing to do. Was Carver liable for the bill, which included the cost of the engine and labor?