2006 Kia Rio AC doesn't work when it's hot outside

I have a 2006 Kia Rio. About a month ago, I noticed that the car’s AC only works when it’s not hot outside. For example, it works when I leave for work early in the morning, but it blows hot air later in the afternoon when the temps outside. Or yesterday, we had an unusually cool day and the AC worked fine all day! But whenever it gets hot outside, the AC will blow hot air! What could be wrong? Relay or compressor clutch, maybe?

I would have an independent AC shop check out your AC. It could be that your AC is low on refrigerant but if it’s low it usually means a leak somewhere.

You have an air door that directs either cold or hot air or a mix. If that is stuck in the “hot” position, you won’t get get cold air. A specialty shop will determine what the problem is but being low on refrigerant will also give you weak performance.


IMO you have the classic symptoms of an undercharged AC system, due to a leak