370 6BTA – breather tube

Greetings,

Just in front of the aft cooler on the 6BTA, there is a small metal tube that comes off the left side of the engine. I assume this is a breather tube of some sort.

I have some smoke coming out this tube, not a lot but it is noticeable.
Is this normal?
Should there be something attached to the tube?

Thanks,
Darryll