Hi guys, i remember my car was quiet inside when i got it year ago, now i'm noticing much more engine noise coming inside the cabin. It happens usualy around 3k rmp, before turbo kicks in, after 4 k rpm it's quiter. Full boost, no leaks. 139K miles on the car, timing belt 85-90 K miles.
What first to check?
Sounds like it's coming from air vents, but i'm not shure.
Can that be oil related ? Or it's idler that bad ?
If someone had it just let me know what it is.