Mine did it once and once only .
The longest thread on this is
The first solution was new lifters.
Then they came out with the new Head.
Now I here they have revised lifters and that's all they will do
and the new lifters that have a different noise associated with them.
Some have tried a heavier oil or additives.
I don't see they can say that it doesn't make a difference since this is
the sound of something hitting on something else.
If it started when you had your oil change try running on the highway to bleed the air
out of the head(original solution from BMW) and make sure the oil level is all the way up.
You have to run the engine up to 3k to 4k for a few minutes.
Last edited by ctuna; 11-29-2012 at 03:16 PM.