breather

Well I went for a drive with a friend the other day for about 1 hour and when we got back and when the car was idling it was smoking pretty bad. The car had never smoked before that and it hasn't smoked that bad in 2 days since it happened. The breather that's on the car has oil coming out of it...

Hi, I'm looking to get a rocker breather filter. Can anybody recommend the the right size (in mm) that I will fit? Thanks,