Some Mini Cooper owners report experiencing severe engine damage, including issues like a warped cylinder head and antifreeze contamination, which necessitate prompt attention to avoid further complications. These owners often face high costs for cylinder head replacement, averaging between $5,569 and $6,059. Symptoms of engine damage may include overheating, reduced performance, stalling, and potential coolant leaks, indicating the need for immediate repair. In cases of significant damage, the engine head must be removed for inspection, as it may be warped or cracked due to severe overheating or head gasket failure. Additionally, when replacing a cylinder head, some owners emphasize the importance of taking precautions to prevent cracking during installation, as this can lead to further issues once the vehicle is operational.