Oil filter micron ratings.

[Jeepster94]

This may be a dumb question.
But is it safe to run 99% at 20 micron filters? Or is there too much flow restriction?
Iv been running the factory PF63 filter on my 6.2 Denali. But now im learning that anything over 20 microns can cause engine wear. And the PF63 is a 98% at 30 micron filter.

 

[ClutchDisc]

I have been running 99% at 20 microns for over 80k combined miles on different vehicles. No issues…

 

[SubieRubyRoo]

Actually, particles below 20 microns cause nearly all of the wear, unless you’re running a Purolator Boss or Wix XP, then you’re getting chunks in the 40 micron range pretty frequently to circulate a few times!

 

[JohnnyJohnson]

This may be a dumb question.
But is it safe to run 99% at 20 micron filters? Or is there too much flow restriction?
Iv been running the factory PF63 filter on my 6.2 Denali. But now I'm learning that anything over 20 microns can cause engine wear. And the PF63 is a 98% at 30 micron filter.

I've been running them for years with zero issues.

 

[UNC054]

You'll have no issues, been running Donaldson oil filters on & off which at 99%@15 Microns.

 

[Brian123]

This may be a dumb question.

Not for a newer member, but for someone who has been on this Board for 10 or 20 years, that may be different!

But is it safe to run 99% at 20 micron filters? Or is there too much flow restriction?

The Oil Filter restriction thing is a myth since some oil filters have a bypass in the oil filter and it might be in the engine block!

But now im learning that anything over 20 microns can cause engine wear.

We do have an Oil Filter Expert on this board who knows everything about Oil Filters and this Micron stuff, he may chime in soon!

 

[Jeepster94]

Whats yalls opinion on the carquest premium’s?
Looks like they are premiumgard filters listed at 99% at 20.
We have an account with AAP through work so i can get them cheap and easily.

 

[Astro_Guy]

Whats yalls opinion on the carquest premium’s?
Looks like they are premiumgard filters listed at 99% at 20.
We have an account with AAP through work so i can get them cheap and easily.

Carquest Premiums are one of the preferred filters around here lately. You may use them with confidence.

 

[EvoMan]

CQP are excellent filters.

G

Post in thread 'Not another Valvoline Restore and Protect thread'

Aug 11, 2025

Love talking filters!

Yes, I’ve called PG several times now and the official PG EX(Extended Life) efficiency range is as follows. This also applies to the 10k filters made by PG for others.(Carquest Premium, Microgard Select etc.)

98.7%@15 microns(absolute)
99.5%@20 microns
99.9%@25 microns

The website has finally been updated for the EX showing 25 as the micron rating. The regular 5k filters are still incorrect and show the EX range like above(15-25).

PG has factories in Vietnam, China, and S. Korea. You will see some slight differences between factories but QC remains fantastic...

• GW.

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[Jeepster94]

CQP are excellent filters.

G

Post in thread 'Not another Valvoline Restore and Protect thread'

Aug 11, 2025

Love talking filters!

Yes, I’ve called PG several times now and the official PG EX(Extended Life) efficiency range is as follows. This also applies to the 10k filters made by PG for others.(Carquest Premium, Microgard Select etc.)

98.7%@15 microns(absolute)
99.5%@20 microns
99.9%@25 microns

The website has finally been updated for the EX showing 25 as the micron rating. The regular 5k filters are still incorrect and show the EX range like above(15-25).

PG has factories in Vietnam, China, and S. Korea. You will see some slight differences between factories but QC remains fantastic...

• GW.

• 
• 

What about the NAPA gold filter? Its a PG But shows 30 micron? Is that just an outdated spec from when they were wix?

 

[Mainia]

You'll have no issues, been running Donaldson oil filters on & off which at 99%@15 Microns.

Please link to who and where to get one. They have a whole handful of filters, what is the automotive version name/color? Also maybe the part# you use and for what car or truck , so we can use that info to track down one for our cars.

 

[EvoMan]

What about the NAPA gold filter? Its a PG But shows 30 micron? Is that just an outdated spec from when they were wix?

Yeah, that’s probably outdated.

I’m currently using either CQP or STP Extended Life filters.

 

[UNC054]

Please link to who and where to get one. They have a whole handful of filters, what is the automotive version name/color? Also maybe the part# you use and for what car or truck , so we can use that info to track down one for our cars.

For my Ram 2500 6.7L Cummins: Donaldson P551018 or the DBL7349.

 

[ZeeOSix]

This may be a dumb question.
But is it safe to run 99% at 20 micron filters? Or is there too much flow restriction?

Flow over efficiency is a myth. Plenty of high efficiency oil filters flow just fine, and your engine won't know the difference in any minor flow difference supplied by the positive displacement oil pump. A few PSI difference in dP vs flow isn't going to matter unless in the are you're racing the engine at near redline most of the time and the flow coming out of the pump is over 10 GPM. Not many vehicles put out that much flow to start with.

Thread 'The Myth of "Flow Over Efficiency"'

Aug 22, 2025

The phrase often used that "Lower efficiency oil filters favor flow over efficiency" has been used here for a long time. The misconception seems to be driven by the idea that lower efficiency oil filters must "flow better" because if they are lower efficiency then the media must not be as "tight" (full of holes), and therefore they must "flow better". That can be a factor, but in reality it depends on many factors in the overall design of the media. When talking about oil filter flow performance on an engine using a positive displacement (PD) oil pump, the term "flows better"...

• ZeeOSix
• Replies: 44
• Forum: Engine Oil Filters

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[ZeeOSix]

But now im learning that anything over 20 microns can cause engine wear.

As already mentioned, it's actually the particles 20u and less. Particles larger than 20u can however get chewed up by moving components and get broken down into smaller particles that could do damage. A high efficiency oil filter will capture more particles below 20u than a less efficient filter. A higher efficiency filter will also retain its efficiency better as it loads up with debris, because oil filters actually lose efficiency as they load up. That's one thing someone can glean out of the ISO 4548-12 efficiency rating. High efficiency oil filters can't have a high ISO efficiency if they shed a lot of already captured debris like a low efficiency filter does.

 

[kschachn]

As already mentioned, it's actually the particles 20u and less. Particles larger than 20u can however get chewed up by moving components and get broken down into smaller particles that could do damage. A high efficiency oil filter will capture more particles below 20u than a less efficient filter. A higher efficiency filter will also retain its efficiency better as it loads up with debris, because oil filters actually lose efficiency as they load up. That's one thing someone can glean out of the ISO 4548-12 efficiency rating. High efficiency oil filters can't have a high ISO efficiency if they shed a lot of already captured debris like a low efficiency filter does.

So many myths about oil filters. Almost as many about the oil itself.

 

[Reloader59]

Actually, particles below 20 microns cause nearly all of the wear, unless you’re running a Purolator Boss or Wix XP, then you’re getting chunks in the 40 micron range pretty frequently to circulate a few times!

Those 2 filters are the only ones? LOL

 

[SubieRubyRoo]

Those 2 filters are the only ones? LOL

Two of the worst offenders with synthetic media, absolutely. Built to withstand a bomb, but like a screen door that will barely stop mosquitoes…

 

[Reloader59]

Two of the worst offenders with synthetic media, absolutely. Built to withstand a bomb, but like a screen door that will barely stop mosquitoes…

Many people use the Toyota filters and they have worse filtering efficiency yet they go 200-300k miles. 40 microns is still smaller than most bearing clearances.

 

[oil pan 4]

This may be a dumb question.
But is it safe to run 99% at 20 micron filters? Or is there too much flow restriction?
Iv been running the factory PF63 filter on my 6.2 Denali. But now im learning that anything over 20 microns can cause engine wear. And the PF63 is a 98% at 30 micron filter.

Baldwin oil filters have been 12 micron since way before it was cool.
It's hard being a 12 micron oil filter in a world dominated by 40+ micron oil filters.
In those days 12 micron normal was a decent diesel fuel filter.