Air conditioning problems are common: compressors fail and require replacement, evaporator cores are cited as a frequent and very expensive failure, and some cars lose refrigerant repeatedly from leaks that are hard to trace. Full system replacement is quoted around $2,900, and multiple sellers proactively replace the compressor, drier and seals before sale.
A/C compressor and evaporator core failures
Mercedes-Benz CLK55 AMG (C208) · mechanical