It seems to me like a sound of valves not getting oil and making that loud rattling noise. It only occurs when I am idling, but will disapprear once I pressed on the gas. Anyone run into this problem before and what was the fixed? I hope it is not going to be a major repair.
BTW - I just changed the oil a few days ago and I put in Mobil 1 0-W40. I normally used Royal Purple 10W40 but made the changed due to the availability of the RP.

 

I have a similar issue with my car. I'm around 70k miles, how many do you have?

 

I have 137,000KM. It is funny but when I used Bardahl 5W40 or Royal Purple 10W40, that sound is not there. I only get it when I used Mobil 1.

 

I seem to have the same problem too. I checked around the engine while
it is running but no luck of the problem. Maybe the belts needs to be replaced
or something. Mine has 45K miles now.

 

Hmm, 10w40 is a fair bit heavier than 0w30... but one of the #'s is at temperature... and the other at some other temperature... hah, i can never remember :P

 

does the noise stop at higher revs?
oil is full i'll assume so its not the amount.

mabye the switch to thinner synth?

 

YES! i had this problem that sound drove me nuts i took it to a mechanic he said he flushed my oil system im not sure how and then put in synthetic not sure what kind. but that fixed it from rattling at idle but it still sounds bad starting up. 50k miles i drive that poor car too hard.

 

Just to let everyone know. I took the car in for service and the diagnosis was MAF for the CEL problem, the rattling sound is for the cam shaft position tensioner, oil leak around the cam and valve gasket need replacement.
Right now I feel like trading my car in because of what the dealer quoted me.
10W40 is not really that thick because it is summer. It may be thick for the winter months, reasons why we should use 5W40 or 0W40.

 

^ Shouldn't you be able to do some of that yourself and save the labor?

Oops...Duh...not everyone has a VAGCOM.