We deal in three year old VW Polo's and have noticed that many 1.4 and 1.0 engines have a noise that sounds like the ends rattling, it is more noticeable when cold, but can still be heard when warm with a blip of the throttle, it is defiantly not the tappet noise, that we are all used to after they have been standing for a few days.
A local VW service advisor confirmed that it was known as a characteristic and it was recorded by VW in a technical manual or bulletin, unfortunately he has left the dealer and nobody else can find the details of this problem.
I did once have this problem before on a 2000 X 9000 mile one year old car was in warranty, and after a lot of pressure a short engine was replaced under warranty, it still rattled a little when first started but was better that before.
The noise is just annoying and I would like to prove to my customers that it is just a characteristic and not a sign that the engine is about to fail.
If anyone can point me in the right direction I would be grateful.
John