This hissing sound is apparent with AC and radio on or off, doesn't change either way.

Sounds like it's coming from under/inside the dash on the drivers side. I only hear it when accelerating, and the noise gets louder the harder the acceleration. During deceleration the noise can be heard to a similar degree. Here's the odd thing, this only happens when the car is in gear and moving. If I'm sitting still and rev up, I don't hear it.

Once I have the car cruzing and level off the throttle, the noise is hardly apparent. However any acceleration or heavy deceleration it comes right back.

The best way to describe the sound is almost like air suction. This is not the heater core air bubble gurgling/sloshing I've read about here. I did go through those steps to purge any air, but from what I can tell, this is most definitely not that symptom at all.

Any ideas?

 

Forgot to mention, 07 SL, just broke 30,000 miles. CVT tranny.

I don't think the noise was there when I first got the car a year ago, but i listen to the stereo loud most of the time, so I may not have picked up on it. I did install a grounding kit under the hood, used the same instructions from one of the sites that sells the kit online. The kit worked perfectly, I noticed more bass from the added sub, interior lights were brighter, and windows went up and down much quicker. The reason I mention that, it was some time after that installation that I first noticed this sound. I can't correlate how it's related, or if it has no bearing on this issue at all. Noise has been there for at least 6 months, kit was install a month or so before that.

 

Nothing new to report, just keeping the thread alive...

 

I'm having same problem to is make noise while driving under the dash. Idk what is it.

 

I have an 07SL with 40k miles. I just started hearing this same thing. Definitely sounds like air in the duct/fiter hissing. I've tried, turning off the A/C, changing the mode from floor to defrost, even turning off and back on. Still happens when warming up the car. I don't necessarily hear it once I'm driving or after the car is warmed up. I thought it was normal for this time of year (kinda like the squeaky strut tower and suspension etc.).

 

My sound is there cold or warm. It's never gone, just fluctuates with the throttle position.

 

Must be the turbos kicking in...
Seriously Keep us informed.

BTW I have the NWP spacers and Via plate with the AEM CAI and there is a whistling sound or a loud hiss when I'm pushing it a bit...I like the noise as it sounds like there's something serious under the hood!

 

Anyone ever find a solution to this?

I have an 07 SL completely stock with this issue, so it's not an issue from modding.

thanks.

 

Maybe there is a vacuum issue somewhere ??

 

I had a hissing issue under my dash and it was the AC hose coming out of the compressor.500.00 from the dealer,thank god for warranties.

 

maybe its that turbo you have thats spooling down

 

I have to look into it myself. I'm just out of factory warrantee now, found that out when I went in the other week.

I have the extended, but they will charge up front, and if it turns out to be something like a bad hose, i.e. a expendable type part, they would bill me and not the warrantee. Taking apart the dash, and fixing something like that could be quite expensive, and I don't want to be against the ropes. I still want to get this fixed, but I'll have to do some investigating on my own to be sure it's something they will cover before I take it in.

What sucks, when the car idles the sound isn't there, so I have to be moving to recreate the issue...

 

Sounds to me like they want to rip you off.... You know what I have noticed now a days with dealerships. They are jacking up everything when it comes to labor and service.

Anyhow man. I had something like this a couple years back with my 05 maxima. It turned out to be my resonator. There was something loose I took it to like 3 dealerships before one of them spotted the issue. They said something had come loose and was causing the noise. I noticed it more when I was at 2k to 3 1/4k Rpms. If I held it steady at like 2 1/2 K rpm's I would hear it real nice.

The noise I would hear in different places. Sometimes in the dashboard area and sometimes by the e-break. I will also mention that the AC hose was broken and leaking. So this issue is kind of a funky one. But all in all they fixed both problems and at that time I was under warranty. But I am pretty sure the issue was the resonator because that hose broke 3 times in less than 2 years.

Hope this helps. Make sure all your pipes are tight & maybe nothing is loose... would be my guess. Because I never asked which section of the resonator was loose and which bolt in this case might have been loose or gotten loose over time which really boggles my mind.

 

Sounds like you might be onto something...what's this resonator, and what's it do? Are you talking under the hood, or under the dash?

 

Its under your E-Break. Under the car. Its part of the muffler system. The one that connects to your Y-Pipe. It a fat looking pipe. what it does is it makes your cars muffler system not make so much noise. When you get a full muffler system you notice it sounds louder because they make the resonator smaller and the tips just compliment the entire system.. If you get a straight pipe. That mess will sound so loud.

Anyways back on topic.
When my car made that noise. They said a screw had come loose. When this happened my car was bone stock. And when I got my Nismo muffler system I really didn’t pay attention to the resonator where that particular issue had started. All I can remember they told me was that a screw or bolt was loose. And they replaced it. I remember the noise sounded like a hissssss Sound and sometimes a little bit raspy.

Go to your dealership and tell them to inspect the resonator and entire muffler system including Y-pipe... There could be something loose you might even have a dent that may have a cracked or something. hence you get a hissssss sound. Like if air is escaping some where. Which brings me to my question. Have you scrapped your car at the bottom ?? like drove up a curve or something that scratched the bottom of the car in the mid section ??

Also do you have a aftermarket intake, manifold or headers?