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I30 N-Line - Burbling/hissing Sound when Cold Start

pkim7371

New Member
Jan 14, 2021
5
2
3
Sydney
Hi All

I am i30 N-line Owner, just curious anyone experiencing burbling/hissing sound when cold start? It always happening at the first cold start for about 30 seconds and the sound 's gone after RPM is down under 1000 rpm. I visited a dealership service centre and they saying it is normal but I never heard this kind of sound before.
 

R Veloster N

Well-Known Member
Mar 5, 2019
6,370
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Rocky Mountains, US
1.5 -1.6T Gamma II Engines are a different animal all together. I own both but what you're describing is unknown. A video or sound track would be a good start.
 

19_EGTNU

New Member
Aug 25, 2019
22
15
3
K1t0k5
Hi All

I am i30 N-line Owner, just curious anyone experiencing burbling/hissing sound when cold start? It always happening at the first cold start for about 30 seconds and the sound 's gone after RPM is down under 1000 rpm. I visited a dealership service centre and they saying it is normal but I never heard this kind of sound before.

If I am correct in what it is you're hearing, lol...

It sounds like a giant milk shake being finished by an elephant. šŸ¤£

That would be the factory wastegate being open I believe. As the turbo, and intake are nearing sufficient boost pressure to close at around the 1300rpm range. And It is 100 normal.

If I'm completely off, my bad šŸ¤· lol
 

19_EGTNU

New Member
Aug 25, 2019
22
15
3
K1t0k5
I've recorded the sound and attached here as a zip file, please try.

Thanks

Phil
Oh Damn!! Did you have your mic directly on the air intake for that sound clip!?

It's sounds louder than mine but it does sound very similar. Mines a 1.6t

I stand for my first guess for what it is. Unless it is for certain a sudden change from the usual, then you may have a vacuum leak, or restriction somewhere (loose hose, bad PCV valve etc.) To be straight with you though I'm not a mechanic haha
 

pkim7371

New Member
Jan 14, 2021
5
2
3
Sydney
haha yes, I opened bonnet and recorded it on my phone, that's why it is so loud. if you hear this sound from inside of car then it is not that loud. I hope this is normal as you mentioned before.

I found a youtube video, this guy having exactly same issue as mine, I put the link below.

 
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19_EGTNU

New Member
Aug 25, 2019
22
15
3
K1t0k5
At first the rain threw a wrench at me, but yes 100 percent normal. Mine does the same. And sometimes it is more noticable/obvious than others.

Some times if the engine isn't up to temperature yet, but I'm reving beyond 1500rpm (I have DCT, so this is almost unavoidable) it does it as well.

I'm positive it is something regulating the air passed the turbo until boost is either sufficient to close or idle is low enough for us to not hear the air movement... I was wrong. Not the wastegate I was totally off, but rather the blow off valve in the open, recirculating the air back into the airbox

Just the nature of our beasts šŸ¤·
 
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19_EGTNU

New Member
Aug 25, 2019
22
15
3
K1t0k5
At first the rain threw a wrench at me, but yes 100 percent normal. Mine does the same. And sometimes it is more noticable/obvious than others.

Some times if the engine isn't up to temperature yet, but I'm reving beyond 1500rpm (I have DCT, so this is almost unavoidable) it does it as well.

I'm positive it is something regulating the air passed the turbo until boost is either sufficient to close or idle is low enough for us to not hear the air movement... I was wrong. Not the wastegate I was totally off, but rather the blow off valve in the open, recirculating the air back into the airbox

Just the nature of our beasts šŸ¤·

Edit: Maybe not the BOV either lol. That's my Q for sleep.

But no issues with what you're hearing. This much I know.
 
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R Veloster N

Well-Known Member
Mar 5, 2019
6,370
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Rocky Mountains, US
Pull the lid to the Airbox and check if you have debris in it. It sounds very much like it's coming from there with debris rattling around. It's not a vacuum leak.

If necessary pull the air box, remove the filter and check for debris in the intake tube. Almost sounds like a varmint has taken up residence in the airbox or intake tube and left nesting material there.
 

pkim7371

New Member
Jan 14, 2021
5
2
3
Sydney
Pull the lid to the Airbox and check if you have debris in it. It sounds very much like it's coming from there with debris rattling around. It's not a vacuum leak.

If necessary pull the air box, remove the filter and check for debris in the intake tube. Almost sounds like a varmint has taken up residence in the airbox or intake tube and left nesting material there.
The sound is happening only about 30 sec on first cold start only, it's never happening after.
 

R Veloster N

Well-Known Member
Mar 5, 2019
6,370
4,677
113
Rocky Mountains, US
I understand, if anything is in the intake tube or the air box upon start up and high idle, it's either getting sucked into the turbo or is settling back to the bottom of the airbox. I wouldn't wait to long either to check it.

I have a 1.6T 2020 Kia Soul GT Line and I've never heard anything similar to it. I can definately tell you it isn't a vacuum leak, or anything like it. There's something that actually sounds like something being sucked up in a vacuum cleaner and the only thing that could resemble it is something in the intake tube or airbox being sucked up, I'd have a look for myself and see it there's not something in either.

If it's doing it every time you start the engine, then I'd be quickly looking and listening to the plastic intake tube. Have someone start it with you on the outside and the hood lifted. Pay special attention to the plastic airbox and intake tube.

It's your car and you can do what you want but I wouldn't accept the dealership explanation. It's s not normal for any 1.6T Gamma II engine, in either a Hyundai or Kia
 
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pkim7371

New Member
Jan 14, 2021
5
2
3
Sydney
I understand, if anything is in the intake tube or the air box upon start up and high idle, it's either getting sucked into the turbo or is settling back to the bottom of the airbox. I wouldn't wait to long either to check it.

I have a 1.6T 2020 Kia Soul GT Line and I've never heard anything similar to it. I can definately tell you it isn't a vacuum leak, or anything like it. There's something that actually sounds like something being sucked up in a vacuum cleaner and the only thing that could resemble it is something in the intake tube or airbox being sucked up, I'd have a look for myself and see it there's not something in either.

If it's doing it every time you start the engine, then I'd be quickly looking and listening to the plastic intake tube. Have someone start it with you on the outside and the hood lifted. Pay special attention to the plastic airbox and intake tube.

It's your car and you can do what you want but I wouldn't accept the dealership explanation. It's s not normal for any 1.6T Gamma II engine, in either a Hyundai or Kia
I might be checking this with local mechanic, I could do wrong things if I do it myself.:)
 
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