Dude! I have the exact same problem your describing. Exactly same. I cant pin down the noise. Im thinking it sounds like metal on metal grinding or the whoosh of air sound. Im not overly concerned but ill get under there tomorow and actually take a look!

 

i have it, now the forte uses a air power brake hose. when i bought my car, this hose had a leak in it that made a white noise sound. it was fixed right away. but i do have the wooshing sound. so i assumed this might be linked

 

Try changing the brake fluid to something else if you can and see if that makes a difference.
Also visually inspect the hose lines to the brakes and see if there might be a leak, these hoses come under heavy pressure when you apply the brakes.
Also before turning on the car, try pumping the brake pedal 10-20 times so the fluid starts moving about, try do to this before the car is warmed up, after doing that 10-20 times, see if it still makes the noise.

 

HellaWhiteKoup: I can't pump the brake pedal 10-20 times without engine turned on because it gets harder after pumping few times. And in my case the noise is gone after pumping once, as if air was locked in overnight and it escapes when I depress the brake first in the morning.

Anyway, I felt this isn't normal so I went back to the dealer and ask them to prove me that other vehicles make noise too. First car I tested had about 10k on it and it did make the same noise but it was barely noticeable if I don't pay attention. Second car with 25k didn't make any noise at all. Then I tested a brand new 2012 (mine is 2011) model, and again it didn't make noise. He told me ones that there were loaner vehicles he tested which aren't here today, but he said they did make the same noise. He said he can replace the brake booster if it can make me happy, but he assures that this problem I'm experiencing shouldn't really be a concern. I told him this is just my guess but there might be a tiny hole in rubber that seals, and the rubber shrinks when it's cold and this could be the reason why the air locks in overnight when the temperature is low. He said this is possible. He order the brake booster so we will see what happens.

Jeffrias: Can you let me know what your dealers said?

 

sjp, I just got into my car tonight when it was raining, about 11c and I noticed the noise you were talking about, I actually heard this noise every time I go to start my car up in the cold weather,it makes this whooshing noise, the noise i heard is actually the pedal itself actuating the fluid for the first time to keep it cycling. This is present in most cars that are stationary over long periods in cold weather, it is completely normal. In most cases its the first pump of the brakes that gets the brake fluid moving, hence the whooshing noise, its very soft, but I can hear it, Its by no mean any danger and it is completely fine.

 

Sjp--- i obviuosly had too many wobbly pops last night because i forgot i was taking my car into the body shop today. ( chick backed into my door/fender when it was parked) so i cant get an answer for yaz right away. I think Hellawhitekoup is onto something with his last post there!!

 

I too want to believe this is normal but I have owned 5 cars so far and I never had this issue, and my forte never did this for a year since I bought it. This noise is loud enough to be heard even with music on... I live in Canada and never heard this noise last winter. I guess I will find next week. If this is normal seriously I will never buy a Kia again.

 

The sound you describe is classic brake booster failure, condensation get's into the booster. Hard to imagine car's this new having this issue, but I guess it is possible.

 

I have what sounds like a person exhaling air when I press the brake pedal with some emphasis on my Forte and also my 2011 Mazda 3. Pretty sure I had the same thing on my previous car as well, a Corolla. I don't believe it to be an issue. If the sound is loud and can be heard when even lightly stepping on the brake, then it'd might be worthwhile to get it checked out.

 

Well I changed my brake booster yesterday but I heard the sound again this morning. What else can go wrong? this drives me nut!

 

Try talking with youre dealer again. There is a rubber bushing behind the brake pedal that sometimes slips & makes the noise you describe .

 

But this only happens once and if I want to reproduce the sound I have to leave my car alone in cool weather for hours. If it is the brake pedal then I should hear it every time I depress the pedal.

When dealer changes the brake booster do they change the vacuum hose attached to the booster as well? I wonder if that's what causes this issue.

 

Hi,
I had my Kia Forte EX sedan for a year and when it's cool/cold if I depress the brake pedal it make some whooshing/hissing sound whether the engine is on or off. I usually hear this sound once in the morning 7:30am and once more after work around 5pm. I less likely hear this on a warm day, and it doesn't make that noise when I'm driving.

I took it to the dealer and they say they can't find anything wrong. They said they checked 3 other car on a lot but they all made the same noise. I don't know if I should believe them because I never heard this noise before from my Forte or any other ones I had before.

Is anyone else having the same problem?

I read a lot of these same things on the web at multiple forums.
From what I gather it is a very minor vacuum leak in the brake booster or lines. When the car sits for a long time the air inside the booster loses the vacuum. When you press on the pedal it is pulling air into the booster to fill up where the vacuum used to be. Once this occurs it will not happen again until it has had enough time to leak off the vacuum again.

To me the worst thing that could happen from this is that your brake pedal would need to be pressed harder to stop the car at some point in time when the leak gets really bad.
If the car is stopping with normal pressure applied to the pedal I would not worry about it.