[sandeepmohan]

This hissing noise was present on my Linea for over a year. Turns out, the air conditioning system was running low on freon. With summer setting in early, I started to notice the climate control struggling to bring down cabin temperature too. This hissing noise was audible only when the blower speed was on the lower side. If the blower was running at higher speeds, the noise of the blower would drown out the hissing noise. Topped up freon a couple of weeks ago and the hissing noise has vanished.

The noise from a turbo is a whine and very faint.

[BigBrad]

I drive a Polo 1.5 TDI and hear the same kind of noise occasionally. It's very similar to the turbo whistle, but feels like it's coming from the a/c vents or somewhere behind the dashboard and not from outside the car. If it was the turbo whistle, then the sound should have been heard every time the turbo spooled up. But that's not the case here.

I'm yet to figure out how to reproduce it at will. I mostly run the a/c in recirculation mode and I think the sound comes even in recirculation mode. But I'll need to verify it once again.

It hasn't bothered me much as it doesn't affect the performance of the a/c or the car in general. The sound has remained exactly the same (without any variation in intensity/frequency/tone) from the initial days till now. My assumption is that it's some quirk of the climatronic system in certain climatic conditions.

[NiladriM]

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[Jebs]

If you hear this hissing sound only while the acceleration , it would be turbo hose pipe leakage only. Just check whether you're getting this sound on the low rpms (below turbo spooling), then you can easily figure it out. I've experienced the similar Ford Fiesta TDCi and the hose was replaced after pushing them to change only that. They were asking me to change the entire turbo setup for the same.

[sajusherief]

Originally Posted by NiladriM

I too tend to think that it's to do with the AC, as I remember now I switched off the AC for sometime and then the sound disappeared. Did you happen to take any advice from your SA regarding this?

NO, only because I was skeptical that they might screw up something else trying to figure out what this issue is In fact right from day one there was a significant audible hissing sound from near the glove box for 2-4 seconds which was told by the SA as a normal scenario. So did not bother to dwell into that too much.

[vickyP]

I hear a similar hissing sound while accelerating on my Vento TSi, although only at times. It is not something that happens everytime or everyday. Generally, I 'believe' it happens on a more than normal acceleration, but I might be wrong. Seems like an AC thing but just wanted to check with fellow users regarding any updates on this?

I would try and test it under different scenarios like AC on/ off, gradual/ hard acceleration and share my feedback to ensure that the sound is from the AC.

Is it worth visiting the service center?

[msudhir]

I have noticed a Hissing sound on my Vento TDI initially thought it was air leak from the front right tire. But on closer inspection it's coming from the front right engine bay and that too when car is idling and AC Switched off. Opened the bonnet and checked but couldn't feel any air leakage but hissing sound quite prominent. Didn't notice any reduction in cooling as yet. Wonder what the problem could be

[R2D2]

Originally Posted by msudhir

I have noticed a Hissing sound on my Vento TDI initially thought it was air leak from the front right tire. But on closer inspection it's coming from the front right engine bay and that too when car is idling and AC Switched off. Opened the bonnet and checked but couldn't feel any air leakage but hissing sound quite prominent. Didn't notice any reduction in cooling as yet. Wonder what the problem could be

Check the vacuum pipes on sensors, brake booster and/or the air ducting from the air intake --> airbox --> inlet manifold. Something may have worked itself loose.

[themanwithcar]

I have noticed the same on My Vento (2015), during acceleration. I hope the sound from the turbo, which usually appears from beneath the Glove Box region.

[Bsilver]

Yes, it is the noise from the turbo during the spool. If you notice this during the boost rpm, then most likely it is the turbo, and other rpm lower than the boost range, doesn't relate to the turbo and has to be something else. This can be heard even more when the recirculation is turned off. Do check all vacuum lines, sometimes this hissing can be mistaken as the boost controller as well, but hard to trace. Hope this helps, a sound clip from engine bay, or the cabin may help.

Happy Motoring!

[Rajeevraj]

Originally Posted by themanwithcar

I have noticed the same on My Vento (2015), during acceleration. I hope the sound from the turbo, which usually appears from beneath the Glove Box region.

I have noticed this in my 2013 Vento TSI. Happens under strong acceleration and does not change if I switch off AC or put it in recirculation mode. The inspection at service centre also did not show anything out of ordinary and final verdict was that it was the sound from the turbo only..