I just changed my air filter (stock) with the STP one because that is all they had, and was wondering about the small green markings on one end of the filter. Both the STP and the old one had this marking, but I did not pay attention to which end the green was on while in the casing. Does it matter which way the filter faces? If so, which end should the markings be on, towards the front of the car, or the rear?

Thanks for the help!

 

Nah they arent directional.

 

doesn't the filter have a rubber lip around it and it only really goes on one way? i haven't seen mine in ages lol

 

They do have a rubber lip, declaring top and bottom, which is very obvious. I was just curious about the air flow and if it went from end to end specifically, but onepoint8tee answered that for me. Thanks guys!

 

Yes air filters are directional. Air has to go THROUGH them.