Noise coming from engine on cold start

[veej123]

Hi, My 2002 Audi A4 2.0 Petrol has started making this noise each time I start it up.
It sounds like a stealth fighter jet! (ok maybe not that loud, but louder than usual)

It started around December, so I think it is linked to the cold weather. The noise stops once the engine warms up.

Any ideas what this could be?

Thanks for your help

[towcestervag]

try switching off air con on start up and see if noise dissappears if it does then its the air con electric fan on the o/s (electric fan)

[veej123]

Turns out it was a dodgy temperature sensor. But the EML light didn't come on! It only came on a few weeks later. It was probably half working. All fixed now though.