A machine "punches" this louvers into the metal filter housing. The oil then flows through these louvers into the filter element to be filtered. The lack of quality control shows that this punch did not fully open up the louvers and the few that did open, the slit opening was very tiny.
Could be just a fluke on mine or maybe the production run created hundreds or thousands of these faulty filters, that is unknown. Will your engine fail when running this filter? Most likely not but it will damage it depending on how many miles you run this filter and what type of debris will get bypassed and pushed back into the engine. Debris could end up scoring the bearings or getting caught into a lifter or something, causing problems many miles later.
The Made in Thailand has punched circular holes, not louvered, but it is clear that these holes are open and allow a lot of oil flow to get into the filter element. Louvered punches are okay AS LONG as they are punched correctly, allowing oil flow. This filter was not punched correctly and it was never inspected, except by me.
Could be just a fluke on mine or maybe the production run created hundreds or thousands of these faulty filters, that is unknown. Will your engine fail when running this filter? Most likely not but it will damage it depending on how many miles you run this filter and what type of debris will get bypassed and pushed back into the engine. Debris could end up scoring the bearings or getting caught into a lifter or something, causing problems many miles later.
The Made in Thailand has punched circular holes, not louvered, but it is clear that these holes are open and allow a lot of oil flow to get into the filter element. Louvered punches are okay AS LONG as they are punched correctly, allowing oil flow. This filter was not punched correctly and it was never inspected, except by me.