Hi everyone, I have a potential issue that is a bit concerning.

When starting my 2.2 td4 auto from cold there is a strange rattling noise/vibration coming from the engine bay. After the car has warmed up the noise disappears completely. The noise only seems apparent when the temperature drops below 12 degrees outside.
The noise reminds me of a noisy water pump. I also tried turning the a/c off but this makes no difference. Its only on tickover that it happens. Once the car has warmed up the noise goes away completely, I've reved the engine and it's smooth as anything.

Any ideas?

Can you tell which side of the engine it is from, can you record the sound and post it here?

Think it is coming from the drivers side.

Lifted up the bonnet this evening, and it's definitely coming from the area of the pulleys.

After doing a bot of searching, I've found this post! This sounds just like what I'm experiencing.

http://www.freel2.com/forum/topic17477.html

Could be the alternator clutch pulley - that will make your belt and tensioner pulley bounce about and rattle like a basteward. If you remove the belt, see if the alternator pulley freewheels in reverse. If it doesn't, replace it. I think I saw a thread on here recently about this with a link to a YouTube video.

Edit: I can't find the post but I've found the video.  Past: FL2 TD4 HSE Auto
Evoque SD4 Dynamic Lux Auto
Present: Audi A3 S Line.

Or maybe the belt tensioner. Seems to go quite often on older vehicles. Ex AA Series III LWB Safari - Gone
300TDi Disco (bought new - terrible car) sent back after 18 months
Freelander 1 Estate - leased, given back at end of lease
200TDi Disco (bought from a mate with 100,000 on the clock) - Gone
Disco 2 TD5 - sold and exported to France
FR2 TD4 GS - Gone
FR2 SD4 HSE - Now changed for a DS
New model ex-demo Evoque S 180 in white
Unable to order a new DS, so gave up. Now have a Volvo S90 Recharge.

Its a 2009 with 65k does that sound about right for a tensioner to pack up? Only noticed the other evening.

I'll get it looked at today!

I had my first aux belt and tensioner done under warranty and I now have the same belt slipping type noise again (Usually only when the air is very damp and the car not used for a while) so I think I could need another new tensioner / belt. Mine is a 2010 on 48,000 miles. FL2 HSE Auto Galway Green
Evoque SD4 Auto Blue.
FL1 HSE TD4 Manual Black - Gone.
RR Classic V8 EFI - Gone

Many times squeak noises, as Steve said, could come from the alternator one way clutch pulley.