Rs5 making a rattle noise

[rs5-ammzz]

hi, just recently purchased a 2010 audi rs5 4.2 b8. cars runs and drives with absolutely no problems whatsoever. but i've noticed it will make a rattle sort of sound when starting up and this sound will last for a second if that. doesn't happen all the time when starting but it is there. just wanted to know if anyone has any thoughts on what this could possibly be? thank you

[morski]

Depending on the mileage and past maintenance history i would think it could be a timing chain or tensioner. usual rattle before the oil gets to it. You can use VCDS to check for timing chain stretch. A rattle for a second or so should not be too much on issue but worth checking