I just went to amend your thread title so that it complies with forum posting rules but it seems there is a discrepancy somewhere?
The picture of the car in your avatar is of an E36 but your title says E46 and in your vehicle details (drop down box) your car is mentioned as a compact but also states saloon.
Is your car like the one in the picture? If so you'll need to amend the vehicle details to say hatchback:thumbsup
It's possible an oil breather pipe may have come off or you have an exhaust leak?
Does the car still run okay?
Noticed a difference in fuel consumption?