Hello all - Just picked up a 2010 G37S coupe yesterday hooray! I noticed tonight when I started it up in the driveway for kicks that there was an intermittent hissing sound coming from somewhere under the car, like to sound of a spray can I guess... I shut the car off after a minute so not sure if it would have gone away on it's own. Really love the car, obviously I'm a noob and don't know what sounds to expect yet... does anyone have an explanation for this (excess gas, etc?). There are no warning indicators on in the car, tires are fine, etc.. Thanks!

 

Quick update on this... went out and started her up again and let her run for a few minutes and didn't hear the noise... still, if you have ideas on what it could have been please reply. I'll update the thread if I hear it again

 

I think it may be the normal sound produced by your catalytic converters but im not sure

 

i believe the sound is normal. I used to hear it all the time on my 08 sedan

 

Anyone else hear this noise... it's pretty faint but I heard it again after a drive. Wondering if I should get it checked out now or wait until the 1000 mile mark when I bring her in for a once over

 

Hmmm never heard this type of noise before... Is it coming from the back or the front?

 

could be an exhaust leak

 

Maybe a/c drip onto hot pipes? Never heard any such noise on my sedan.

 

maybe an exhaust leak... sounds like if you hiss through your teeth intermittently, pretty faint but there... sounds like it's coming more from the back. I'm planning on sticking my head under there tonight and will update back if I can get a more precise location

 

But an exhaust leak wouldn't be intermittent if the car is on, would it? It should be constant or maybe pulsate, but not be intermittent. That's why I said a/c/ drip.
The fuel pump makes a light hissing sound but it's more constant, too. It's back near the rear passenger wheel I think.

 

You sure u don't have a supercharger under the hood

 

Don't think it's an exhaust leak since it is intermittent and a hissing sound... wouldn't an exhaust leak make the car sound more like a lawnmower?

 

May be just a normal thing... I've found other posts that say it's not an issue (or at least that's how I'm choosing to interpret them

Hissing sound from underneath car - Nissan 350Z Motoring Forums

hissing from exhaust, when getting off the throttle? - Bimmerforums - The Ultimate BMW Forum

Likely I'll just wait until my 1k check-in and raise it with the dealer unless I notice any performance issues before then

 

I think it's normal, at least I hope it is cause mine does the same thing. I think it comes from the converters. I've had it looked at and no one knows what it is

 

our engines are not very quiet and can make random noises sometimes. As long as your service engine light isn't on and you don't notice a performance loss, i wouldn't worry.

if you decide to bring it to the dealers attention, make sure you can reproduce it or else they will use that famous line 'cant reproduce problem'