I would have to agree with this quote!! I analyze everything......sometimes I hate myself for that

 

The video is not loading for me because im at work right now, however i know there is a hissing noise that results from broken servo motors. These are the same motors that regulate the cool/warm air flow into the cabin.

Also, do you know any of the OEM AC components have been replaced?

 

Oh look... a problem my car DOESN'T have for once. I for sure have never heard this noise in my LS and I am pretty attentive to noises when the music is off.

 

I think that we all hear these noises because the LS is so quiet!....If it was a camry then we wouldnt be on this subject

 

I just got back from the dealer and showed the noise to the tech. He said that he makes no guarantees, but it amy be to a low level a refrigerant in the system. He said that on other cars, it usually gets rid of the noise if it is infact the case. And yes- some cars are more audible than others. Mine is pretty loud

 

If you're concerned by it I'd suggest taking the car to an A/C place (over here most auto electrical workshops do A/C also) and having them check the system's high and low operating pressures. If all is within spec it's likely a sticky TX valve.


Justin...

 

I have the same noise. It is only audible when the AC is on. The noise is not related to the fan or air flow. The accessory drive belt is not a factor in the noise (in my situation, at least) because I changed it out with a brand new OEM one and it didn't change the noise.

The most plausible explanation for me is as stated above - "You might just be hearing the gas atomizing at the metering valve of the evaporator coil."

 

I had the same noise and the mechanic found my refrigerant level to be low, he filled it to the proper level and the noise went away.

 

Good to know! Do you know how much refrigerant was missing/added? Did you get this done at a Lexus or Toyota dealership or elsewhere? How long did it take and what was the cost?

Since it is a closed system, if the refrigerant is low, wouldn't that mean there is/was a leak somewhere? Did they perform a leak test on both front and rear AC?

For those that want to check for insufficient refrigerant, run your engine @ 1500rpm, set front and rear blowers to HI, driver/passenger/rear AC to MAX COOL, and fully open all doors. Look through the sight glass and if bubbles exist, you have insufficient refrigerant (unless ambient temp is higher than usual and cooling still works).

 

This was two years ago, I was missing about half of it. Got it done at independent mechanic. He couldn't find a leak, it must be a tiny one. I've been having another issue though, my A/C takes about ten minutes to start blowing cold air. It only does this if the car has been sitting for a long time, like overnight. Nobody can figure out what is wrong with it. I just had it recharged again, it was 2lbs low. The delayed cooling problem still exists, and the noise has come back too. I think maybe the tiny leak has now gotten big and I've lost a lot of refrigerant again. I have to take it back to the shop and see if they can locate the leak and find out why it takes so long to start blowing cold air, even when it has full refrigerant level.

 

Update: Problem fixed!
I am the original poster.
Thanks to responses, I asked the dealer to recharge the AC and the noise went away. The tech did not think recharging would fix the problem so I had to promise not to hold the dealer accountable if the noise remained.
Thank you. I like my car again.

 

the expansion valve is mounted on the firewall if you will. if you look at your car and see where the ac lines go into the cabin of the car, they bolt to a round aluminum thing. that thing is the expansion valve. they are known to be noisy. being low on refrigerant could cause the noise. if it is something that truly bothers you, have the expansion valve replaced. but a new one could be almost as noisy.

 

I thought i was going crazy. I have been hearing this noise for some time and thought i was the belt as well. Then i was able to narrow it down to the AC, but i thought it had to do with the fan inside the car, similar to the issue that the e46 3 series has. My car is CPO, will they cover the AC recharge?

 

It is virtually impossible to have an absolute seal on high pressure gas (liquid is entirely a different matter and very easy to have an absolute seal). The leak is very small and is allowed by Lexus specs. Over a matter of a few years, the freon level can be expected to be low. When they recharge a system they generally add a dye that is detectable with a UV light so they can find an excessive leak. Really the only check the technician can make is to visually confirm that there are no air bubbles in the sight glass and then check the A/C discharge air temp to confirm that it is in spec.

Just a good idea to have the system checked and recharged every other year at least.