LSJr Take on Oil Filter Efficiency Improving with Loading

[garageman402]

I haven't been keeping up with his videos, but I saw this one & commented. His reply is here:

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@themotoroilgeek


1 day ago

Oil filters do get better(increased efficiency at smaller micron sizes) in actual use. The principles of filtration are the same for air, oil and fuel filters. The difference you noted actually comes from the difference in how air filters and oil filters are tested. Air filters are fed test dust at a steady rate over time, so that you can measure efficiency vs loading. Unfortunately, oil filter testing begins with oil that is fully loaded and then continuously adds contaminated oil. As such, the ISO 4548-12 standard does not produce an efficiency vs loading graph. This is where you can see the initial loading of the filter creating a "dust cake" within the media that increases the efficiency of the filter for particles smaller than the absolute particle size.




This goes against everything discussed here on this forum, proven by @AscentFiltrationTesting, backed up by @ZeeOSix. I replied with evidence from this thread:

Would you all like to see ISO 4548-12 Oil Filter Lab Testing Comparison, Efficiency & Capacity, Pressure vs Flow, Bubble Point, and Burst?​

But have not received a reply. Any thoughts on his comments?

 

[altaylar]

He is wrong on that point. End of stroy

 

[twX]

Unfortunately, oil filter testing begins with oil that is fully loaded and then continuously adds contaminated oil. As such, the ISO 4548-12 standard does not produce an efficiency vs loading graph.

ISO 4548-12 does measure efficiency vs loading. The efficiency is measured by comparing the number of particles downstream of the filter to those measured upstream. These measurements are done in real time with particle counters. It doesn't really matter that the test is closed loop instead of open loop, or that dirt is added over time.

The principles of filtration are the same for air, oil and fuel filters.

Air filtration is quite different to oil filtration. There are many different mechanisms for particle filtration. They apply to both air and oil filtration, but some of these mechanisms are much more dominant for low viscosity fluids like air, and others for high viscosity fluids like oil.

Oil filters do build up a filter cake, and this should help increase efficiency, but there are other mechanisms at play that counteract that effect.

 

[GW.]

Lots of discussion here.

G

Thread 'LSJR on the importance of clean oil'

Dec 20, 2025

This probably belongs in the oil filter section. Lake explains the importance of high efficiency oil and air filters. Micro abrasives don’t mix with extended oci’s. Frequent break in oil changes are highly recommended to remove debris.

One thing I don’t agree with him on(dirty oil filters are more efficient), oil filters do not get more efficient with use. ISO 4548-12 clearly shows this.

• GW.
• Replies: 287
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

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[garageman402]

Lots of discussion here.

G

Thread 'LSJR on the importance of clean oil'

Dec 20, 2025

This probably belongs in the oil filter section. Lake explains the importance of high efficiency oil and air filters. Micro abrasives don’t mix with extended oci’s. Frequent break in oil changes are highly recommended to remove debris.

One thing I don’t agree with him on(dirty oil filters are more efficient), oil filters do not get more efficient with use. ISO 4548-12 clearly shows this.

• GW.
• Replies: 287
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

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Yes, Glenda, I read part of that thread that went sideways quick, & was shut down. I actually read that after I started this thread, lol. I haven't watched the video you quoted yet, as I said I fell behind. There were two videos with the live chat with the three Donaldson guys, either one started with a different "foreword".

 

[EvoMan]

But have not received a reply. Any thoughts on his comments?

At about the 1 hour mark they were talking about oil flow and oil filter bypass. Lake stated that he has a video coming out in January that talks about that. Maybe there will be something in that video about oil filter loading and contamination.

 

[garageman402]

Lots of discussion here.

G

Thread 'LSJR on the importance of clean oil'

Dec 20, 2025

This probably belongs in the oil filter section. Lake explains the importance of high efficiency oil and air filters. Micro abrasives don’t mix with extended oci’s. Frequent break in oil changes are highly recommended to remove debris.

One thing I don’t agree with him on(dirty oil filters are more efficient), oil filters do not get more efficient with use. ISO 4548-12 clearly shows this.

• GW.
• Replies: 287
• Forum: Passenger Car Motor Oil (PCMO) - Gasoline Vehicles

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My bad, I did watch this video, I just re-watched it to see if I missed anything. I did, he did casually mention that in passing. The video I referenced extensively says that efficiency increases with loading.

 

[KGMtech]

Filtration loading improves removal of smaller stuff, but it also affects flow, so pick your battle?

 

[mojoe]

Interesting! First I've heard of this.

 

[EvoMan]

My bad, I did watch this video, I just re-watched it to see if I missed anything. I did, he did casually mention that in passing. The video I referenced extensively says that efficiency increases with loading.

Were they talking about air filters or oil filters?

If oil filters, at what minute mark was it?

 

[kschachn]

Filtration loading improves removal of smaller stuff, but it also affects flow, so pick your battle?

Even so, is flow ever a practical consideration for any commercial filter in a passenger car?

 

[ZeeOSix]

ISO 4548-12 does measure efficiency vs loading. The efficiency is measured by comparing the number of particles downstream of the filter to those measured upstream. These measurements are done in real time with particle counters. It doesn't really matter that the test is closed loop instead of open loop, or that dirt is added over time.

Exactly. LSJr doesn't seem to have read or understands the ISO 4548-12 test document. The test is a real time efficiency measurement of the filter with calibrated particle counters upstream and down stream. The rate of debris loading depends on the estimated holding capacity of the filter - ie, so larger filters can typically be loaded with higher test dust concentration because it takes longer to fully load them and get to the test ending dP. Ascent used a dP of 8 PSI over new filter dP at test flow rate to stay out of filter bypass.

I have never seen any ISO efficiency test data that shows an oil filter gets more efficient with loading before it becomes basically totally clogged. But by that time the bypass valve will probably be ready to open too.

 

[ZeeOSix]

Filtration loading improves removal of smaller stuff, but it also affects flow, so pick your battle?

Not seen from the ISO efficiency data that Ascent got. Look at the posts in the locked thread that plots the efficiency over time for different particle sizes. Here's a good one where @OVERKILL plotted the ISO test data from the particle counters.

Post in thread 'LSJR on the importance of clean oil' https://bobistheoilguy.com/forums/threads/lsjr-on-the-importance-of-clean-oil.402805/post-7461941

 

[JunkdrawerDog]

Does this mean I can run my OEM gravel strainer forever?

 

[GW.]

Interesting! First I've heard of this.

Hopefully Donaldson responds.

 

[mojoe]

Hopefully Donaldson responds.

I followed up today with a reminder. So far nothing. I would really love to hear their take. I find it hard to believe that LSJR has not.

 

[Oliveoil2]

I’m a fan of the filter-loading increasing efficiency theory. The past 20 years I’ve done 10-20k on oil filters (2 OCI’s depending on vehicle) and 50-80k on all air filters. The air filters look horrible but the cars run well and there is no decrease in power or MPG.

 

[GW.]

I followed up today with a reminder. So far nothing. I would really love to hear their take. I find it hard to believe that LSJR has not.

I’m data driven. Show me the money

 

[ZeeOSix]

^^^ From another thread where this is discussed. The link in the post below (another official ISO 4548-12 test done on some oil filters for use on Kitplanes) also shows what Ascent's ISO efficiency testing showed ... that oil filters lose efficiency with debris loading. I have not seen one ISO efficiency test that shows otherwise. That's real data, not some assumption that oil filters act like air filters in terms of how the efficiency changes with debris loading. Also read post 55 and beyond in the thread below.

Post in thread 'Lake Speed Jr Visits Donaldson Company to Get Information About Air Filters'

Dec 16, 2025

I came across this write-up and thought I'd add it to this thread since oil filter efficiency change as the filter loads up was discussed, and this is good information on the subject - see link below. This is also data from an official ISO 4548-12 test lab which also shows the decrease in oil filter efficiency as they load up. Look at Figures 3A and 3B. Figure 3B shows what the efficiency was when the filters were basically new and unloaded with debris. Figure 3A shows what the overall ISO 14548-12 efficiency was taking into account the debris loading. The ISO 4548-12 test procedure...

• ZeeOSix

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[ZeeOSix]

I’m a fan of the filter-loading increasing efficiency theory.

They don't with oil filters. The "theory" is a misconception.