2002 E46 - Rattling noise sometimes only

[ndsolo]

Dear Sifu's,A few months ago I floored the gas and the next day a noise appeared. It comes only during cold start and lasts for about 5 seconds.Last Wednesday I sent my car for servicing and decided to change the oil separator. The engine is so much more quiter and responsive. The noise is now more audible and it comes sometimes when I accelerate, even at low speed.I got my mechanic to hear and he said maybe it's to do with the catalytic converter. He lifted the car up and checked but could not confirm and told me to wait until the noise gets to be more constant.My mileage is now 110km. Anyone come across the same kinda noise?Thanks very much and have a good day.

 

[Vincent Hor]

Ndsolo, your E46 which model? I am assuming it's a 318i valvetronic. Some engine noise is quite normal for this engine but it would be abnormal if it's a 6 potter.