You guys sure like to argue! It really is not a big deal, in the 1950's lots of car makers didn't even run oil filters on their engines. Who cares if they leak. As I said, Toyota prefers loose, leaky engine oil filters, they last sometimes 300,000 or more miles like that sometimes.
I really like the OEM vs High Efficiency debate. I can see both sides. Personally I choose filters that are high efficiency and high flow so I get the best of both worlds.
Now paying a premium for a “high efficiency” filter that has poor craftsmanship and defects is another debate…
One reason Toyota oil filters irritate me. I will post this flashlight test, several filter companies use this style of bypass valve built into the leaf spring, It makes no sense to me that oil filter companies keep using this design, knowing unfiltered oil will go through, even with a brand new unclogged oil filter.
So to get back to the original topic of this thread….
A question was brought up as to why the filter companies use this style of leaf spring for the bypass valve.
This question is answered rather easily, it’s all about the cost. It’s very simple for a stamping machine to produce a leaf spring. While a coil spring is a better design, it’s manufacturing ease and overall cost that keep the flawed design.
I really like the OEM vs High Efficiency debate. I can see both sides. Personally I choose filters that are high efficiency and high flow so I get the best of both worlds.
Now paying a premium for a “high efficiency” filter that has poor craftsmanship and defects is another debate…
What filters have so much dp vs flow that it's going to make an engine not receive adequate oil flow and lubrication? If you compared 10 oil filters with hot oil, and the dP at 8 GPM was only +/ - 2 or 3 PSI from the group average, then the flow difference when the DP pump is in relief won't really matter.
Also, just because a filter is lower efficiency doesn't automatically mean it has a lower dP vs flow curve.