I have a fairly faint but annoying just the same a/c air blowing noise coming from the driver's side vent. Shutting the a/c off does not seem to change the noise. It sounds like something is blocking the air in the vent. It's not always there. Any clues?

 

Can you describe the noise? Is it the vent between the instrument cluster and the driver's door?

Mine makes a kind of rustling sound from time to time. I think I may be low on refrigerant.

 

It's the driver's side vent closest to the driver's door. Rustling is a good description for the noise. No problem with refrigerant here as I can hang meat in my car with the a/c on.

 

Even though your air is cold it can still be low on refrigerant. Low refrigerant can cause a rustling or whistling sound from a valve that is located in this area. The sound will only occur if the a/c compressor is on though. My car has a tiny refrigerant leak somewhere under the dash, and it's not worth spending two thousand dollars to remove the dash to find it. Once every 12-18 months I start to get the whistling sound and I know it's time to top up my system with a can of 134a.

 

If this were the case and it had a refrigerant leak, wouldn't the a/c eventually start blowing warm? In addition, I get the noise with the compressor off as well.

 

you just might be low on refrigerant. It doesn't have to be a leak. And that could be causing your noise problem.

Refrigerant makes a similar sound to water running through pipes when it is very low.


Your air condition can still be cold, but not able to achieve maximum cold temperature.

Top up your refrigerant and see how that goes.

 

Thanks again for the info. Interestingly enough, I was recently checking the temperature from the vents on the Lexus to check on a possible issue with my Jag. The Lexus was blowing at 40 degrees. Could I still be low on refrigerant?

 

No problem Bocat.

I'm honestly not sure what the AC should blow out when it's in "COLD".


Here in Oregon the weather is really great most of the time, so I don't use my A/C very often, but when I do I get a similar sound in my drivers side. I think I might be low on refrigerant too. But where it's at is more than enough for me since I rarely ever use the A/C.