mikesd1980

When I start my car in the morning it makes this noise that sounds like a jet engine. It make the noise for about 2 mins than it shut down. It comes from the passenger side of the engine. Didnt have a chance to look under the hood yet. It only does it at start up in the morning. Its fine the rest of the day. Any info?

A8 LOOONG

Check under the hood. It sounds like your air intake assembly is sucking un metered air into the engine. Are you running the stock air box?

mikesd1980

I have the stock air intake. Everything is stock. I had my oil change today and the air filter box had a hole in it. Didnt think nothing of it. I ordered another air intake(stock) to replace it. Would that be the reason for it?

MP4.2+6.0

my instinct from your first post was it could be the air injection pump that I think these motors have. Pretty standard smog equipment. I'm not an expert by any means on this part of the car, but from my C5 4.2 I think it is a black plastic looking fan impeller housing, one on each side of the motor if I recall. In turn, that "hole" you found could perhaps be where the fitting for the hose the pump uses to draw in filtered air, which then is pumped into the exhaust side of the motor air flow. Again, my C5 4.2 has a fitting on the air box of about 1" in diameter to which this hose attaches.

If not, then yes the hole in box is a theory. I'm suspicious of the air pump though since I think those run at start up to light the converter off quickly by getting more fresh air in there.

A8 LOOONG

That sounds like exactly what your problem is. Air pump, pumping air and a hole in the box whooshing the air making that sound. My question is, how do you get a hole in your air box?

mikesd1980

Actually I might have to give the dealer a call on this one. When they changed my parking light on the passenger side in Feb. The SA told me that the one of the air filter box nuts was stripped. I found that hard to believe cause I do my own oil changes and I know if I would have stripped it but let it go. The noise started around 2 weeks ago but didnt know why. It was time for another oil change and when I removed the air box it had a hole in it. It look they pulled the box where they claim the stripped screw was and tore of the tab that screws down and put a whole in the box. The funny thing is that they put some type puddy around it and put it back together and didnt say anything. Didnt expect that from this dealer.

MP4.2+6.0

First the air box as you mention, but then perhaps the disconnected/broken air pump line.

Not infrequently I find an Audi problem now isn't one where it just broke afresh, but rather something got disturbed from some other repair.

koolaid

The airbox has a hose that goes to the Secondary air injection pump. To change the oil filter the airbox needs to be removed. Its possible that the hose was not secured properly at your last service.

jeremy_matrix

Definitely sounds like the secondary air injection pump is simply getting louder with time. VERY common on most VAG's.

Can the sec air pump eventually come apart internally? Yes, but more often this sec air jet engine type whine is just more of a nuisance than anything.

Bunky

This noise definitely seems to be getting louder on my 04 as the years go by. Not a problem, but certainly noticeable from inside the car for the first two minutes or so from cold start up.

I opened up the air filter box the other day to check that the secondary injection tube was connected, and it seems to be, so maybe the pump is just getting louder with time as jeremy_matrix suggested.