Maybe all filters do this, I don't know but I just noticed it. Changed the oil on the Trailblazer and this is the new Fram Ultra XG3506. The old one (2 years old) also was like this. Why both?
It's new technology ... a column of louvers next to the seam gives 10% better flow.
It might be like that by design and some sort of manufacturing process - especially if two have the identical thing going on.
Look at the spacing pattern compared to the other holes in the center tube ... they don't match, so they don't look like attempted hole punch outs to me. Maybe Motorking can look into this and see.
Nothing is going to "break off" in that center tube.
They have had the secret louvers for years. Louvers, holes, burs, Frams have it all. Oh wait those aren't burs on a Fram, just metal pushed out around the holes.
I think that filter looks good that is how they looked for a long time the holes look ok here.. Who knows they could change anytime although Motorking wrote me very early this morning at 4:43am saying Fram will be keeping the round holes so lets just hope. His words were no plans on changing current center tubes.
Thank you Motorking.
There may be some more holes near the base that the camera does not see.
I like to see a lot of oil holes on the center tube myself it just looks like it will flow better. The ultra is a nice filter hope they stay that way and they don't get sloppy
Originally Posted By: tig1
Why so many holes at the bottom of the filter, but none at the base end? Poor design, or manufacturing problem?
I was wondering the same thing. Seems that would reduce the flow a lot.
Things like this make me want to use the e-core filters sometimes, no restriction at all with those.