Why Does My Car Idle Rough When I Turn on The AC?
When you turn on the air conditioning (AC) in your car, it places an additional load on the engine, causing it to work harder. This additional load can cause a rough idle, which can be attributed to several factors.
One factor is the compressor clutch engaging when the AC is turned on. The compressor is driven by a belt connected to the engine, and when it engages, it creates additional drag on the engine. This drug can cause a rough idle because the engine has to work harder to compensate for the added load.
Another factor is the idle air control valve (IAC). The IAC is responsible for regulating the amount of air that enters the engine when the throttle is closed, which is necessary for maintaining a stable idle speed. When the AC is turned on, the IAC may not be able to compensate for the additional load on the engine, resulting in a rough idle.
How to Fix Rough Idle When AC is On?
To address the issue of rough idling when the AC is turned on, you can try the following solutions:
- Check the compressor clutch: If the compressor clutch is not engaging properly, it can cause additional drag on the engine, resulting in a rough idle. Have a mechanic check the compressor clutch to ensure it is functioning correctly.
- Clean the IAC: The IAC can become dirty and clogged over time, leading to a rough idle. You can try cleaning the IAC with a can of throttle body cleaner and a soft-bristled brush.
- Replace the IAC: If cleaning the IAC does not solve the problem, it may need to be replaced. Have a mechanic check the IAC and replace it if necessary.
- Check for vacuum leaks: Vacuum leaks can also cause a rough idle. Have a mechanic check for any leaks in the vacuum system and repair them as needed.
By addressing these potential causes of rough idling, you can ensure that your car runs smoothly when the AC is turned on.