Hissing noise under dash when ac on?

[joegr]

$130 sounds like a fair price.
I think that you get the sound when the system is low on refrigerant. I don't think it matters where the leak is.

 

[mmm]

$130 sounds like a fair price.
I think that you get the sound when the system is low on refrigerant. I don't think it matters where the leak is.

I was kinda thinking that as well....not sure if leak on high side or low side would make a difference though....

$130 sounded pretty decent to me too, though I'm not sure exactly how much work it would require to replace a schrader valve.

I'll post an update to see if this fixes it.

 

[joegr]

...$130 sounded pretty decent to me too, though I'm not sure exactly how much work it would require to replace a schrader valve.
...

Recover refrigerant.
Unscrew old valve core.
Screw in new valve core.
Pull vacuum on system.
Recharge system with refrigerant and oil.

 

[manoli]

UPDATE:

Just got the diagnosis from the dealer.

Leak at the high side schrader valve is what they are claiming.

They said they normally charge $339 for this fix alone, but are giving me a cut in price since I already dropped $530 and then had to take it back again. They are charging me an additional $130.

I am going to get it fixed in a couple of days when they get the part in.

Has anyone else had this type of leak and if so were you also getting a suction sound??
Does the price sound right??

Thanks

I had this issue last year dealer charged me $180.

 

[mmm]

Just picked up car and A/C is working great. Really cold air on both driver and passenger and no vacuum / suction / hissing noise.

The dealer did not have the valve so they did not replace (not till Friday) and they did not charge me anything, but my air is working great now.

My guess is they recharged it.

I am not really sure what they did, because the service advisor had me pick up the keys directly from him rather than from the cashier and he just said to call him when I wanted to return to have the leak fixed. He mentioned that he held the keys because he didn't want them to charge me, but at the time in my head, i was thinking, "okaayyy, why would they charge me if I didn't have additional work done." It was only when I got into my car and turned on the air that I realized that something had been done.

Anyways, from that I'm guessin' he had them recharge it for me for free. Didn't know "nice guy" service advisors existed, ha....I'm still taking it back in on friday to have the high side schrader valve replaced so that my A/C stays cold.

So I guess the diagnosis for hissing / suction noises behind the dash is low refrigerant. If that changes, I'll update.

Thanks.

 

[manoli]

I also noticed that the hissing noise went away today after having my ac charged Hope my ac doesn't give me anymore problems it's almost 90 outside lately.

 

[Four eyed stangs]

My ac quit right after making the hissing noise in the dash.
As soon as I started charging it, it worked again.
As soon as it started working, yellow oil started running out of a valve by the low pressure port. The leak continued until the pressure would no longer allow the clutch to engage.
Is this the (A/C) Pressure Relief Valve?
Can I replace it?

 

[chris bange]

So after hearing this same hissing / suction noise (can hear when my AC is running) for about a month and a half my AC finally decided to go out and blow only heat.

After reading many threads suggesting that the LS has a somewhat unique AC system, I decided it was best to take it to the dealer.

Turns out my DCCV or Coolant Control Valve (as they called it) went out. Went ahead and had the dealer replace, which I am still not sure why, because I definitely could have done it myself, but after 530 bucks later, my AC now blows cold again, BUTT

still have the mysterious hissing / suction sound coming from behind the dash. It will slightly hiss at idle, but if i go at least 5mph, the hiss will get loud, then stop and then after a few seconds, start low hissing again, slowly creeping up to a loud hiss and then stop. It pretty much repeats this over and over and over.

Oh, and the air from my driver side is colder than my passenger side.

Was wondering if anyone has found a fix for this yet.

I am kinda glad I did have the dealer replace the DCCV now, because they are going to diagnose this hissing sound tomorrow and not charge me an additional diagnostic fee. Which should have been included anyways, because I would think that their initial diagnostic should have included a pressure check of the AC system, especially if the customer comes in for an AC issue. I think they only did a code check and code said DCCV.

Anyways, if anyone has any info on this problem, please let me know. I will update on what they come up with.

Thanks...

I have the exact same symptoms to a T! I've replaced the dccv in the past. Regained cold a/c while having the hissing issue from the expansion valve. but currently is not blowing cold air again in just the way you explained. Please leave a follow up on if the expansion valve issue fixed your ac being warmer on the passenger side.