Hissing Noise

[candi04]

This may be a stupid question, but I'm asking anway. This is all new to me. My car was idling this evening and I could hear this "hissing" noise coming from under the car (I think). The compressor was not on, nothing was on inside the car, but it sounded like it was cutting on and off. Could someone please tell me what that is?

I am going to listen for it again in the morning, but I just thought I'd throw this question out there in case it's normal.

[G_whizz]

BUMP...anyone??

[joe603]

hissing huh...more info is needed.

1. Have you done anything to the car...ANY mods?

2. You have to locate the source...check for the sound while the hood is open...might be a vacuum line.

3. Last, check your AC lines. I had hissing once and it was my alt fan cutting into my AC line...hissing the refrigerant charge into the air .

[candi04]

I just bought the car on Saturday, no mods yet.

I will listen to it this evening again to see if I can figure out where it's coming from exactly.

[rn79870]

Sometimes I hear a hissing noise comming from my rearend too.

[candi04]

Sometimes I hear a hissing noise comming from my rearend too.

Pay attention, I didn't say it was coming from rearend. lol

[rn79870]

Slow leak in a tire?

[joe603]

Slow leak in a tire?

If it was that, then the low tire sensors would go off (hopefully)

[rn79870]

Have you checked your coolant lately? If it's low, you may have a slow leak in a line somewhere.

[candi04]

Slow leak in a tire?

Well, it's not a constant his. Almost like a compressor noise. I thought about a vacuum leak, but I will have to pin point it and get further information.

I just heard it last night and thought it might be as simple as "Oh yeah, that's your blah blah blah"

Guess I was wrong. LOL I'm still learning the car, I just don't know what's normal and what not yet.

[joe603]

You might be hearing the fuel pump...more of a high pitched whine than a hissing though.

Does it go away with a small blip in throttle?

[candi04]

You might be hearing the fuel pump...more of a high pitched whine than a hissing though.

Does it go away with a small blip in throttle?

I haven't tried that. I was just idling.

From inside the car, it sounded like someone was sitting outside somewhere with a can of spray paint. You know that "spray" sound?

[Sentientbydesign]

One of my pulleys is making a hissing sound. You might look there too. I'm going to take it into the dealership to have them look at it.

If the sound gets higher in pitch when you step on the throttle, I'd say it was a vacuum line of a pulley, but there could be other possibilities too.

[joe603]

Any update?

[telcoman]

Any update?

There appears to be a hissing sound coming from chair that I'm sitting in.

Just finished lunch

[joe603]

I thought that was just a description..."old fart".. hehehe

[rn79870]

There appears to be a hissing sound coming from chair that I'm sitting in.

Just finished lunch

Sounds like too much back pressure, check your relief valve...

[candi04]

Sounds like too much back pressure, check your relief valve...

You guys are not right!!

I tried to listen last night, I didn't hear anything then, but I was also freezing when I did this. I will look at it a little more this weekend as it warms up and I can raise the hood.

I will keep you posted.

[candi04]

I have had the flu all weekend, so I STILL have not gotten to really check this out more thoroughly. Sorry for the delay..

The flu sucks!!

[Imran87]

I am actually hearing the same noise on my car as well...i would love to know the problem.

[SVTCOBRA]

I think you can rule out a vacuum leak. If you had a vacuum leak that bad your engine light would be on and it would be idling extremely poor.Your local Nissan or Infiniti dealer service tech might be able to listen for a quick minute and tell you what it is.

I assume that your engine light isn't on and it is idling smooth???

[candi04]

Yes, it was idling smooth when I heard the noise. No lights are on in the dash.

[joe603]

any update?

[johnparkyourcar]

I'm curious too, because my car makes those sounds once in a while. Also I noticed that when I accelerate kinda hard, theres a whistling sound, almost like a turbo spooling up...

[smockers83]

Are you guys sure its not just air getting sucked into the engine? Because that will produce a slight hiss, because my car makes a hiss too, but its just the air getting sucked in and the engine running. At least I hope so. Stick your ear next to the intake or just close to the engine in general with the hood open. If that's it then I think that's what you're hearing.

John--do you have the POP Charger? If so, that's normal.

[johnparkyourcar]

The hissing sounds loudest by the rear wheels.... But it is definitely not the tires, it sounds like it's coming from underneath the car but where the wheels are. And as for the sound as I'm accelerating, the intake would explain everything hahah I can't believe I never thought about that

[johnparkyourcar]

I think you can rule out a vacuum leak. If you had a vacuum leak that bad your engine light would be on and it would be idling extremely poor.Your local Nissan or Infiniti dealer service tech might be able to listen for a quick minute and tell you what it is.

I assume that your engine light isn't on and it is idling smooth???

Kinda off topic but after reading that, it reminded me of a dream I had last night that my car broke down from a problem like that, where I ignored the check engine light. Scared the crap outta me and I checked up on my car after I woke up just to make sure it was a dream hahah.

[Sentientbydesign]

Most of the aftermarket intakes will make a slight hissing/whooshing noise. ESPECIALLY, the onces with screens on them. Most of you are probably familiar with the K&N style (cotton and metal) or the AEM dry-flo (synthetic fiber w/ plastic reinforcement). There are also filter elements which have metal screens like the ones you'd find on a window, but finer.

They make BOV sounds, but at the wrong times . I remember a del sol asking me if I was boosted because of the filter.

As for the hissing from the rear tires. Could it be the fuel pump?

Or an exhaust leak?

[johnparkyourcar]

If its either the fuel pump or exhaust leak, would that affect my daily driving, or would it be ok to leave it like that until I get around to fix it?

[Sentientbydesign]

The fuel pump supposedly makes that noise normally. I've never heard it though.

The exhaust leak is probably a quick cheap repair. I'd take it to a muffler shop and ask them.