When done correctly, installing a used engine can be a simple procedure, but it's important to know what to anticipate. Prior to installation, ensure your mechanic checks the engine for compression, wear, and oil leaks. An engine that is fitted incorrectly may cause more issues and expenses. After the used engine is installed by a trained professional, your car could require some tweaks to function properly. Be ready for minor tweaking or changes to the engine control unit (ECU). A second hand engine can bring your car back to full operation without the expensive cost of new parts if it is installed and maintained properly.