Its the secondary air pump running quite normal.

Air is pumped into the exhaust to weaken off emisions whilst the cat is warming up. It also aid in actual cat warming aswell to bring the light off time down.

Thanks Ross, nice to know I'm normal!

Some of you have got bad information on your threads about noisy cold start.I drive a 03 VRS with 22k on the clock.At about 18k a noise start on cold start up,this noise got progressively worse and started to last longer.I took the car back to my very helpful dealer.The problem turned out to be a secondary pneumatic pump that sends exhaust gases to the cat.(this is an Audi part not skoda) was at fault.My dealer changed this part without question, his feeling was that this part was changed on more then a few Audi TT under warranty.if you need anymore info on this subject contact me cheers!!!

The Article here was written as a direct result of frequent questions about unusual noises from under the bonnet of the Octavia with the 1.8T engine. To the best of my knowledge, Derek, your car is the first on this forum to suffer from secondary pneumatic pump failure although I could be wrong. In your case too it was a new noise which rightly needed investigating. My car has made all the noises mentioned in the Article since I bought it with 1500 miles on the clock and continues to do so. If any of those noises change significantly I too will visit my dealer.

The Article here[/url'] was written as a direct result of frequent questions about unusual noises from under the bonnet of the Octavia with the 1.8T engine. To the best of my knowledge, Derek, your car is the first on this forum to suffer from secondary pneumatic pump failure although I could be wrong. In your case too it was a new noise which rightly needed investigating. My car has made all the noises mentioned in the Article since I bought it with 1500 miles on the clock and continues to do so. If any of those noises change significantly I too will visit my dealer.

Dennis thanks for your reply,when my dealer removed the secondary pump they noticed that the housing on the pump was coming apart,it was this that was causing the noise on cold start.The dealer also said that after they talked to audi about this fault,that it was a regular fault on TTs and they changed many of them under warrenty cheers!!!

Derek' date=' Can you describe the noise you had, mine is running like it has a blowing exhaust for the first 30-40 seconds when it starts up in the morning accompanied by a slight almost misfire sound, then whatever causes it switches off and it's fine again, thing is it doesn't do it every morning, just occasionally

dave[/quote']

Thanks dave for your intrest,the noise that i was hearing got louder over a short time,it was there every time i started the car from cold,Ross info. is correct but if the noise is getting worse and lasts longer then 60seconds i would get the dealer to have a look at the secondary pump housing,it was the housing that was coming apart on my car cheers!!!

I have had an issue with intermitent strange clatterings sounds on my Octy vRS since November. The dealer has changed the starter and the secondary air pump. But I still get alarming sounds on cold start up now and again. For the first 4 months I owned the car it sounded 'normal', but since then I get this intermittent problem of grim mechanical sounds going from under the bonnet. The dealer has also checked all the cam gear and tells me nothing is wrong. This problem is really starting to effect my enjoyment of the what I thought was a great car. When the car is good I love it, but on the odd times the noise rears it's head, I think what a heap of junk why did I buy this heap. The thing is, it's not a heap, it's not even 3 years old and cost me thousands of pounds. Initially I thought the nosie might be related to colder winter weather, but we are now in summer and I still getting odd days when the car sounds like a heap of scrap when it starts.

Any advice as to how to go forward?