Grinding noise after starting car

[Nigma]

Hi,
Recently I've noticed a dull grinding noise towards the front of the car. It's only really noticeable when sat in the car through vibrations. Can't be heard outside.

1. Happens after I start the car, gets much quieter after a few mins of driving.
2. Only prominent when idle
3. Weather clutch is pressed of depressed has no effect on the noise, likewise if in gear or not.

Its a 98 1.8T

Cheers
Anand

 

[Nigma]

Narrowed it down a little to underneath the car. The box closest to the front of the car.

Only obvious at low revs.

Cheers,
Anand

 

[Broken Byzan]

All the time, or only after a cold start?

Its common for a noise on cold start up, it's the secondary air pump it stays on for 30 secs ish on cold start