This car is a 2004 A8 4.2L 40v V8 with 125k and a good maintenance history.
This engine would clatter lightly and briefly upon cold start-up... something that I was not terribly concerned about. I suspect valve train noise.
It is now 300 miles into the rinse phase and I just happened to notice the other day that this start-up clatter has completely disappeared!
ARX Plus is great stuff!
Mike
