Hissing from the front.

[special--k]

Seems as though when i get out of my car there is a "Hissing" sound coming from the front end. It doesnt last long, and is usally gone by the time i can get the hood up to investigate. I always wait 30-45 seconds for the turbo, and it seems to have only started happening with the cold of winter.

Anyone know whats going on?

 

[SpeedAdiction20]

Only thing i can think of is possibly something is leaking, like some possible radiator leakage somewhere? hoses all good and everything? and is it wet when your hearing this or is it all the time?

 

[special--k]

it has been wet outside... there is nothing on my driveway... and you would think that what ever is leaking would be empty by now.

im sure its not the end of the world, there is nothing different about the cars performance... and the engine still sounds good.

i will keep my eye on it.

What about you? what happened with your car? are you going to buy it back? I might be interested in some of your mods, depending on the shipping prices.

 

[SeR_Cyclops]

i think it would be the turbo spinning because mine does the same thing its more of a shhkhhhkhhhhkhh than a whistel.

 

[NCZ13]

its the air coming back out of the intake.

my car does it too. When you kill the engine theres air thats now stopped moving, so it goes out the path of least resistance, which is back out the air filter, thus the hissing noise.

 

[TropicalDelight]

its the air coming back out of the intake.

my car does it too. When you kill the engine theres air thats now stopped moving, so it goes out the path of least resistance, which is back out the air filter, thus the hissing noise.

+1

 

[speed1016]

Mine sounds like static sometimes! Got me its done it for over a year on and off

 

[dmention7]

its the air coming back out of the intake.

my car does it too. When you kill the engine theres air thats now stopped moving, so it goes out the path of least resistance, which is back out the air filter, thus the hissing noise.

Uhhh, no.

There are a lot of things wrong with that, but I guess all you really need to know is that any air inside the intake tract has stopped moving with any appreciable velocity, virtually the instant the engine stopped turning. (Unless you've got a giant turbo and you kill the engine while bouncing off the rev limiter)


My money would be one of two things: either the turbo slowly spinning to a stop (whenever the engine is running, the turbo is spinning). Or, vacuum being slowly released from some solenoid or valve. On my car I can almost always hear the turbo spinning down, and often I'll hear what sounds like a vacuum hiss as well for only a second or so after opening the door. The turbo though, sounds more like a soft metallic whirring than a hiss.

 

[NCZ13]

How is what you described any different from what I said.

Air going into the engine has stopped moving, therefore any air between the throttle plate and the filter has stopped, and seeps back out the intake, making an audible hissing noise. I noticed this after installing my intake well over a year ago.

I guarantee if he put the stock intake back on, the hiss would go away.

its not that big of a deal and isnt something he needs to worry about.

 

[SpeedAdiction20]

hmm, ya I was thinking about that, but I forgot that the turbo is actually spinning whenever the car is on... which actually might be my issue too lol, I can hear it sometimes on cold starts, I thought it was a belt, which is might actually be, but I guess the turbo is a possiblity...

As far as my car goes I'm buying it back no matter what, but I'm going to get it checked out first and see if it is possible to resurect.. the insurance guy est. it at $10k or so for repairs and after I buy back the car I'll get $9.7k so if there is not really any hidden damage, an extra $1k and I should be good to go possibly... would be sweet as hell to get it back.. otherwise I will tear it apart for parts and have a giant F/S during Christmas break lol.. I'll keep things updated on my other thread, I should know in general what I will do by Monday hopefully.

 

[dmention7]

How is what you described any different from what I said.

Air going into the engine has stopped moving, therefore any air between the throttle plate and the filter has stopped, and seeps back out the intake, making an audible hissing noise. I noticed this after installing my intake well over a year ago.

Because air that's stopped between the throttle plate and filter has no physical reason to be moving at any net velocity once the engine has stopped. And even if there was a slow current of air somehow flowing back through the filter, it would not make a hissing noise.

"Hissing" is a characteristic of fluid moving at high velocity through a small orifice--a small vacuum leak, for example, or an isolated area of vacuum slowly returning to atmospheric pressure after the engine stops drawing a vacuum on the intake manifold.

Another explanation I have heard with regards to the MZR (though I don't know if this applies to the FS's fuel system) is that the engine maintains pressure in the fuel rail for a short time after shut down, and the release of pressure can be audible... I'm not sure how plausible that one is though, since it's my understanding that the fuel pump would have to continue to run in order to maintain pressure in the fuel rail.

 

[dmention7]

I can hear it sometimes on cold starts, I thought it was a belt, which is might actually be, but I guess the turbo is a possiblity...

If you can hear it at idle, over the engine sound, it's more likely a belt than the turbo. A turbo that noisy would have to be pretty much toast... heh

 

[BOOSTR]

Pressurized steam can make a hissing sound when it is escaping. But the msp can be weird, on more than one occasion when my car has been off over night and say I o to check the plugs or do something else mundane in the morning it makes a strange noise that I have no been able to track down or explain. And the engine is off and key out of the ignition with all doors closed.

 

[MSP2k3]

Pressurized steam can make a hissing sound when it is escaping. But the msp can be weird, on more than one occasion when my car has been off over night and say I o to check the plugs or do something else mundane in the morning it makes a strange noise that I have no been able to track down or explain. And the engine is off and key out of the ignition with all doors closed.

I think i know what your talking about, mine has done the same thing on occasion... doesn't happen all the time, its random. Only lasts for 5-6 seconds or so.

 

[SpeedAdiction20]

^^^ Your car is obviously mad at you and hissing to tell you to leave it alone haha.. you have a transformer for a car(stfu) lol ya sorry, just woke up, random thought..(coffee)

Edit: damnit MSP2k3 you beat me to the post... oh well

 

[BOOSTR]

I think i know what your talking about, mine has done the same thing on occasion... doesn't happen all the time, its random. Only lasts for 5-6 seconds or so.

Exactly its short in duration and very random. I thought I was nutz the first time it happened.

 

[special--k]

How is what you described any different from what I said.

Air going into the engine has stopped moving, therefore any air between the throttle plate and the filter has stopped, and seeps back out the intake, making an audible hissing noise. I noticed this after installing my intake well over a year ago.

I guarantee if he put the stock intake back on, the hiss would go away.

its not that big of a deal and isnt something he needs to worry about.

I am on stock air box.

 

[special--k]

it seems to happen randomly.

I was looking in, and i might have a small leak in my A/C line... but that is still to be confirmed. I really hope not, because that would be a b**** to re-fill next summer.

 

[speed1016]

+1 random static noise for about 5 seconds. I was actually under the car when it happened one day, scared me and I jumped jacked my head all up. Couldnt tell where it came from cause I got scared. LOL Im guessing it was around the ac compressor, only because thats arund where I was at the time.

 

[georgecastaneda]

i have no turbo but i can hear that hising noise coming from the CAI, is there anyway possible i can get rid of it?

thanks