Strange blowing noise...

[clockwork.satan]

Hi all,

I've not been on here much at all recently (in fact, I can't even remember the last time I was!) as my 2006 A4 S-Line Tdi (140) has behaved impeccably for 3 year's now without a single problem.

For the past couple of weeks now however, I've noticed that it has developed a really strange noise and I'm hoping that someone else on here might have experienced this. In 4th, 5th and 6th gear (and occasionally even in 3rd), at around 1500rpm i can hear what i can only describe as a 'blowing' noise, which sounds like it's coming from the air vents. I've also noticed that the engine seems to sound 'louder' in the cabin, especially when it's cold. I've also felt a little hesitation in 1st gear and I don't know if I'm imagining it or not, but it feels like it could be slightly down on power.

I found this link: http://www.tyresmoke.net/forum/topic...e-above-60mph/ , which seems to point to a build-up of leaves and gunk in the drains. I got my mechanic to look at it and sure enough the drains were blocked and have now been emptied and cleaned, but the 'blowing' noise still persists. I told him yesterday that the noise is still happening and he's filled me full of dread by saying that it could be the start of the dreaded balancer shaft failure and has booked it in again for next week, but something is making me think that it could be more like a leak in a boost hose or perhaps even an air-con issue... Any suggestions?

[Alan02]

By your description, I would hazard a guess at a Turbo boost hose split, or a loose hose clip....or, a leaking Intercooler. Sometimes not easy to spot.

[SKnibbs]

Keep revs above 1500 rpm anyway, engine and turbo will be happier that way.....

don't doodle a tdi too much.

[meatpie48]

Hi all,

I've not been on here much at all recently (in fact, I can't even remember the last time I was!) as my 2006 A4 S-Line Tdi (140) has behaved impeccably for 3 year's now without a single problem.

For the past couple of weeks now however, I've noticed that it has developed a really strange noise and I'm hoping that someone else on here might have experienced this. In 4th, 5th and 6th gear (and occasionally even in 3rd), at around 1500rpm i can hear what i can only describe as a 'blowing' noise, which sounds like it's coming from the air vents. I've also noticed that the engine seems to sound 'louder' in the cabin, especially when it's cold. I've also felt a little hesitation in 1st gear and I don't know if I'm imagining it or not, but it feels like it could be slightly down on power.

I found this link: http://www.tyresmoke.net/forum/topic...e-above-60mph/ , which seems to point to a build-up of leaves and gunk in the drains. I got my mechanic to look at it and sure enough the drains were blocked and have now been emptied and cleaned, but the 'blowing' noise still persists. I told him yesterday that the noise is still happening and he's filled me full of dread by saying that it could be the start of the dreaded balancer shaft failure and has booked it in again for next week, but something is making me think that it could be more like a leak in a boost hose or perhaps even an air-con issue... Any suggestions?

If it almost sounds like the car is breathing through the vents on the left hand side check the connections to the turbo. I had this issue after an accident so returned my car to the insurers & the mechanic revealed the pipework going onto the turbo was not on properly.

[lynalldiscovery]

I would agree turbo hose split, basically the engine starts to work properly at 1500 rpm upwards as the turbo spools into life and pressurises the intercooler pipework, its a common fault on all turbo vehicles, normally easy to spot by the tell tale signs of oil spatter.

[clockwork.satan]

Oh, I should've come on here to say - the noise wasn't a blowing sound at all, my mechanic traced it to a rattling heat shield that was only rattling when the engine was within a certain rev range. So glad it wasn't anything serious!

Thanks for the help though, guys.

[lynalldiscovery]

Time for a hearing test

[clockwork.satan]

Time for a hearing test

Haha! I was totally convinced it was a blowing noise. Oddly enough, there was a severe lack of power which was reset by him doing a reset via VAGcom to the ECU. Or something. I thought the noise and power issues were linked, but they weren't at all.