Factory A/C is a widely acknowledged weak point: the engine-driven (GM/Harrison) compressor systems are failure-prone, marginal on hot days, and expensive to keep cold. Common remedies include R12-to-R134a conversion (some report under $400, others a fuller job), DIY system rebuilds around $1,500, and reconditioning the vacuum pods; buyers should expect A/C work.
Air-conditioning weakness and R134a conversion
Mercedes-Benz W123 · mechanical