AC Noise

[Murderjetz]

Is it normal for my engine to be making a "whirring" sound when the AC is turned on? I say "engine" because the sound follows the RPMs/sound of the motor.

Here's what happened:
I first noticed this sound a couple weeks ago (although I've only been needing my AC since then), and it didn't seem okay for it to be doing that so I made an appointment at the dealer. Between that time, my AC decided to completely crap out (good thing I already had an appointment set up anyway), at which point the sound stopped, but my AC wasn't blowing cold air either, only the air of the fan.
I brought it in, they told me I needed a freon recharge or something like that, they fixed it, and the AC is back, but so is the strange sound.

it would just seem weird to me that it would be normal for an AC to be making an unpleasant/annoying sound like that.

[habitat]

Yes, the AC is essentially a compressor driven by a belt connected to your crankshaft. When you turn on the AC the clutch engages and the engine is powering the AC. This is why if you press the AC button while your car is off but in the "ON" position, you get no AC.

[Murderjetz]

well yeah, I know that the engine powers the AC. What I'm really asking is, is everyone else's AC irritatingly loud? sometimes it's only a very slight sort of humming sound in the background, and that's fine, but often it comes in with a loud DDRRRRR. I know this is probably a really dumb question/subject, I'm sorry. but it just doesn't seem normal to me for the AC to be so noticeably loud, I've never seen any other car that did that.

[volvo9]

Originally Posted by Murderjetz

but often it comes in with a loud DDRRRRR. I know this is probably a really dumb question/subject, I'm sorry. but it just doesn't seem normal to me for the AC to be so noticeably loud, I've never seen any other car that did that.

When I worked for Acura, all of the new cars a/c and all of the newer Honda's ac compressors made that same loud DRRRRT sound when the a/c was first turned on after not being used for a couple of days, so when my Si did it i wasn't alarmed at all.

The compressor will make a light whirring sound when it's on that changes with engine rpm, but if it's loud then you should get it checked out.

[Murderjetz]

I see...
so should it quiet down after using it for a while? it's still doing it now after three days of on and off usage.

[volvo9]

Originally Posted by Murderjetz

I see...
so should it quiet down after using it for a while? it's still doing it now after three days of on and off usage.

The whirr, or the funky noise when it turns on? I don't think that BRRRRT noise will ever go away, I literally heard it on every new honda made vehicle at the dealer, but only after the ac was off for a while.

The whirr will also always be there, I don't have my Si anymore but even my current car makes a light whirr noise from the compressor that I can pretty easily hear when revving it lightly in the driveway. But like I said earlier, if it's actually pretty loud, then there could be a problem.