The short answer is Yes, The AC compressor affects the engine. The compressor is the heart of the air conditioning system, and it has a direct impact on engine performance. The compressor circulates cooling gas throughout the system, and it helps to cool and pressurize the cooling gas. The AC compressor is driven by a belt connected to the engine crankshaft. When the A/C is turned on, the compressor puts an extra load on the engine, which can slightly reduce fuel economy and increase emissions. In addition, If the compressor is not operating properly, it can cause the engine to overheat, and it can also affect the performance of the A/C system.