I have a 54 plate Octavia Elegance 1.9 TDI DSG with 19k miles and have noticed a knocking noise sometimes from the front left of the dashboard (or the bulkhead behind it). It only lasts for a short while, usually after starting from cold and sounds like some one knocking on the bulkhead at a rate of about 2 knocks per second. This happens whilst stationary so it is not motion related and it is too slow to be engine related. It is not a metallic sound and disappears after about 10 'knocks' or if I turn off the Climatronic air con. Is it related to the Climatronic air con unit? Any suggestions?

Ken

Sounds like the Climatronic messing about, could be the air recirc flap which is over in that part of the car IIRC.

I got something similar recently after I had removed and refitted the glove box... panicked about what the heck it was and what I had busted - but only did it once or twice and hasn't done since... but my hunch was something to do with the climate control.