2015 Fit EX. 103,500 miles. In the last 2 weeks a strange whistle has developed when the A/C is on. Actually sounds like a turbo. An ideas?

 

Bad fan bearings? But, you say it only happens when the AC is on?

 

Yes only with the A/C on. Sound coming from under the hood.

 

Compressor and/or clutch. Possibly the belt due to additional load.

 

Ours has developed a "whistle" sound only on 2nd speed of fan only on fresh air.....any other setting is quiet....and it sounds like internal to the dash, not gonna bother trying to chase it down, it's a minor annoyance

 

FWIW, I had the condenser replaced on my '16 LX a year ago. No whistle noise, it just stopped blowing cold air.

If you had something stuck in a vent, the whistle would occur at the same fan speed whether the A/C is on or off.

So if the whistle only occurs with the A/C on, it might indicate a refrigerant leak. That's where I'd start.

 

For what it's worth, My 2018 Fit Sport w/CVT has a similar "whistle" that is only noticeable when accelerating slowly, at around 20-25 mph. The pitch increases with speed, and very much sounds like a turbo. The first time I heart it, I was looking around trying to figure out where the big diesel truck was that I was hearing the turbo whine on. It does this with or without the A/C on, so I have just chalked it up to the CVT. It's a quiet sound, and everything is super smooth, so I'm not worried about it.