Noise from engine when HVAC kicks on

[twoexplorers]

Does anyone know what starts and stops spinning in the engine when the HVAC kicks on and off during "Auto" operation? It's a squealing, buzzing, whining kind of combined noise and hard to describe but it's definitely new and louder than what you normally hear when the HVAC is cycling on auto. If I turn the HVAC completely off the noise is never heard and I can't hear it inside the vehicle (2015 Limited AWD, no tow pkg). The sound appears whether the heat or A/C is on and it's not constant while the engine is running nor does it change when moving or increasing engine RPM.

It just started two days ago, a day after I had to have the battery replaced due to the last one dying on me at just over 28k miles. I have one month left on the 3/36k warranty so if this is something that's going to keep getting worse I'll have it looked at. Otherwise it will go away when I turn it in to lease another one in August.

Thanks in advance. Any help is appreciated!

 

[asull85]

My first guess would be the fan.

 

[Jon M]

Considering we're heading into summer, I would say get it fixed, or be annoyed with it for 6 months.

 

[twoexplorers]

Considering we're heading into summer, I would say get it fixed, or be annoyed with it for 6 months.

I'm leaning towards that anyway but was hoping to identify the part making the noise. If it's something I can do on my own inexpensively I would consider that because replacing the battery required an appointment 3 days down the road in their quick service lane which is supposed to be a walk-in shop. They are just really busy all the time I guess and it's inconvenient to leave the vehicle all day.

 

[chazglenn3]

It's under warranty. I would have them fix it and tell them you need a loaner.

 

[peterk9]

Does anyone know what starts and stops spinning in the engine when the HVAC kicks on and off during "Auto" operation? It's a squealing, buzzing, whining kind of combined noise and hard to describe but it's definitely new and louder than what you normally hear when the HVAC is cycling on auto. If I turn the HVAC completely off the noise is never heard and I can't hear it inside the vehicle (2015 Limited AWD, no tow pkg). The sound appears whether the heat or A/C is on and it's not constant while the engine is running nor does it change when moving or increasing engine RPM.

It just started two days ago, a day after I had to have the battery replaced due to the last one dying on me at just over 28k miles. I have one month left on the 3/36k warranty so if this is something that's going to keep getting worse I'll have it looked at. Otherwise it will go away when I turn it in to lease another one in August.

Thanks in advance. Any help is appreciated!

Welcome to the Forum.
I don't think there are many "spinning" items under the hood. You have the fans, the alternator and the A/C compressor pulley. That pulley engages and disengages as required by the compressor. The compressor runs when defrost is on.

Peter