That depends on your financial situation, the overall condition of the car, and your personal preferences. Engine replacement is more affordable than people realize and has become one of the fastest growing segments of the automotive industry. It can save you tens of thousands of dollars compared to buying a new car. Just as there are many new car owners who invest in other key components such as transmissions and clutch assemblies, millions of owners each year elect to replace their worn out or damaged engines as well. As a rule, replacing the engine only makes good economic sense if the rest of the car is in relatively good condition and will have a market value close to blue book after installation.