What exactly is this noise???

[prizmatik]

I recently purchased this 2001 A4 with 1.8T quattro manual tranny. It is making an odd noise, and I cant pin point the issue. It only occurs in gear, at low RPMS. I have been underneath the car to try and pin point the issue, but the sound only occurs when under some sort of normal load. When the cars wheels are in the air, I cant replicate the sound.
To me, it sounds as if its coming from the transmission/clutch. BUT, everything has been working perfectly.
The noise sounds almost like something is rattling against the firewall.
Let me know what you fellas think.

[prizmatik]

Bump!

[trev718]

I hear a little bit of a dentist drill(turbo) on the last video towards the end...Your turbo is on the way out..
Mine is making the same noise

[prizmatik]

I agree regarding the turbo, but I cant figure out what the main noise is.

[10kredline]

Sounds like a loose bolt somewhere. Does it happen only when the car is moving?

[prizmatik]

Sounds like a loose bolt or nut to me too. I can only replicate the sound when the wheels are on the ground (I tried to replicate in the air on my lift), and in gear with a small amount of throttle at low RPM's.

[prizmatik]

I had the chance to get underneath my car today, and I found out what was causing the noise. The bolt that secures the sub-frame on the driver side rear was loose, causing the bolt's washer to rattle. Come to find out, the bolt is stripped, but I was able to tighten it enough to stop the rattle. If it loosens in the future, I will weld the washer to the bolt, so it doesnt rattle. I love simple fixes, its figuring out the cause of the problem, that can drive you crazy.