AC compressor noise?

Hi,

I only have a 2010 Prius but during 90+F, high humidity, I noticed the A/C compressor was making a noticeable buzz outside of the car. I only heard it because I had to jump out of to help my wife but I hadn't noticed it before.

As I walked around the car, the compressor noise seemed to be uniform and omni directional. Yet as soon as I sat in the cabin, it was muted. If I rolled down a window, I could hear it echo off the wall.

Have any current or former NHW20 owners noticed the A/C compressor noise?

What surprised me is I thought we had a scroll compressor. These things are supposed to be very quiet. So hearing the compressor didn't make a lot of sense.

Bob Wilson

I haven't noticed anything, but I haven't walked around the car listening for a sound, either. I'll look for it at the next opportunity.

You said it has a "buzz" sound -- How do you know it is the A/C compressor?

Bob, I noticed this same buzz in an exact situation like yours.

When the hot weather returns, I'll double check but I didn't hear air noise like a fan might make. We have just rain today but when the hot weather returns, I'll re-run the test ... shoot looks like a couple of days of rain.

Bob Wilson

A scroll compressor is still a cyclic device. See the animation
I dug up off the net somewhere, and note that it's pushing a new
quantity of refrigerant out the center hole every time it goes
around. It's not a turbine.
.
You also have whatever noise the 3-phase motor and the scroll
eccentric mechanicals make and as much switching whine as comes
from the inverter, so all told it's not going to be dead-silent.
You've heard the a/c system in the second-gen cars too, right?
.
_H*

Bob,

I just bought my 2010 Prius Saturday. During test drives I never noticed this sound. My wife an I drove it all around town all day Sunday and, again, I noticed no unusual sounds.

But when we pulled into our garage I heard this loud buzzing that I swear I had never heard before. I got out of the car and it was quite loud, coming from under the hood. When I shut off the A/C it went away.

Since then, I have noticed that the sound comes and goes. Now and then I will stop the car, get out and listen, and it is gone. I should also mention that I live in Florida and it is 94 out and very humid.

I took the car to the dealer and had a technician listen to it. He claims it is a "normal" sound. At first I was concerned, but I have seen enough posts here that I believe he may be right. This just may be a normal sound I have never noticed before in my excitement. After you buy a car, you start looking and listening a lot closer than you did before.

I'd be curious to know if the sound in your car comes and goes like mine. That's what the technician said it would do. Is yours always buzzing, or does it quiet down at times.

Me too ++. My car does the same thing. It's good to know that mine isn't the only one.

In addition to the flow noise described by hobbit, Oldham coupling in a scroll compressor produces some unbalance, so there is always a little vibration.

Tom