The engine's serpentine belt drives the AC compressor, which requires more energy from the engine. You may actually notice a slight decrease in performance and fuel economy when the air conditioning is engaged. ... You actually could turn the AC on to help cool down the engine if the electric engine fan is not working.
Does the AC cool the engine?
Your auto's AC isn't just to keep you cool – your car needs it too! ... Your car's air conditioning has the important job of controlling the temperature in the cabin of your car and in your engine. This keeps your vehicle's engine from overheating, and keeps you from you being stuck high and dry on the side of the road.
Does AC help with overheating?
Step One to Reducing Engine Heat
The air conditioner can cause an engine to overheat quickly because it makes the engine work harder. Even though it's hot outside, if you turn off the AC, you may be able to avoid overheating, especially if you take the next step, which we apologize for in advance.