FWIW...what I know: I use them and I know from examination of my own filters that they work as-represented. I also know that ferrous/magnetic particles (iron and steel) are the hardest/most abrasive of the wear-metals in circulating engine oil. What I don't know: Whether or not it really matters in the greater scheme of engine wear over time. Seems like a good idea to me...quite easy and convenient. I will continue. The particles trapped are not "shavings" at all but microscopically tiny things that present as a paste or slurry trapped on the inside walls of the used filter...as shown in the many videos available. I wish the various video "reviews" would show the nature of this material and measure fhe actual particle size of its composition. I strongly suspect that many (most?) of them are, indeed, sub-20 microns in size, likely capable of passing through the filter media...but, again, don't know.
I have cut open oil filters and looked. You can definitely see where a small amount of metal is collected where each magnet rests. As others have stated, the oil flows from the outside in. Even so, if what you said is true the magnets would still attract the ferrous metal pieces.
![Oil Filter MAGNET Comparison [NO ONE ASKED FOR THIS!!!]](/img/n.gif)
FWIW...what I know: I use them and I know from examination of my own filters that they work as-represented. I also know that ferrous/magnetic particles (iron and steel) are the hardest/most abrasive of the wear-metals in circulating engine oil. What I don't know: Whether or not it really matters in the greater scheme of engine wear over time. Seems like a good idea to me...quite easy and convenient. I will continue. The particles trapped are not "shavings" at all but microscopically tiny things that present as a paste or slurry trapped on the inside walls of the used filter...as shown in the many videos available. I wish the various video "reviews" would show the nature of this material and measure fhe actual particle size of its composition. I strongly suspect that many (most?) of them are, indeed, sub-20 microns in size, likely capable of passing through the filter media...but, again, don't know.
Except that oil is pumped into center of the oil filter, then through the filter media, then is finally able to reach the magnet.
Wrong...exactly the opposite.
Wrong! It goes through the outside and then it goes up through the middle.
I have cut open oil filters and looked. You can definitely see where a small amount of metal is collected where each magnet rests. As others have stated, the oil flows from the outside in. Even so, if what you said is true the magnets would still attract the ferrous metal pieces.