2014 BMW 525i F18 Weak A/C: Mechanical Compressor Diagnosis and Replacement
A 2014 BMW 525i F18 with an N20 engine and 158,000 km produced vent air above 15°C even though the compressor made no abnormal noise. Case pressure behavior, a clear expansion-valve check, and normal condenser-fan logic supported an internally worn, low-output compressor rather than an electrical fault. Replacement, refrigerant-circuit service, evacuation and charge by the vehicle label were followed by improved pressure relationships and 4–6°C vent air in the reported idle check.