niceone

I am noticing a loud rattle on cold start for approx 2 or 3 secs and then disappears. On subsequent restarts, I still hear a rattle but not as bad. Am I looking at a timing chain replacement ? Car has 87K miles and has been regularly serviced.

Greg5OH

chain probably fine. Audis tenisoners SUCK. search your VIN for a TSB. probably a bulletin out for it. aka free fix.
my q7 TDI does it randomly too.

MP4.2+6.0

For OP, more info please. Helps orient relevant responses if we know your year, motor, and sometimes at least general geography/country.

mtnboydl

My 4.2 will have loud valve clatter on start sometimes, but once the oil pressure comes up after a second or two it goes away. Same thing with my old 2.0T.

PhillyVance

He has a 2012 3.0 TDi.

MP4.2+6.0

If you mean the OP has a TDI, isn't the answer maybe obvious? Its a ...diesel. And if it got the Audi dieselgate fix, one of several different things Audi was manipulating in its fraud was the "diesely" start up sound. Post fraud fix, apparently the start up truck clatter is somewhat more pronounced again.

By contrast if it is gas/petrol, then some other things come into play as possibles.

PhillyVance

Its definitely a diesel, you actually answered another question he had about a load of check engine lights. You told him to change the battery and he did, poor guy hasn't had the car long. I had a 2006 jetta tdi pre deiselgate and it cold started up loud as well. Maybe check the egr?

Greg5OH

im 99% certain what he is referring to is the chain tensioner. These diesels are very quiet. Chain tensioners make a very distinct clacking osudn and you hear the chain flopping around as well. Goes away after about 1.5 seconds.

Check your VIN against the national database of TSBs