PF66 Filter Comparison - What am I missing?

[1pt21Jigs]

I’ve been using the FRAM Ultra XG12447 on my 2025 GMC Yukon with the 3.0L LZ0 Duramax. Based on the ISO 4548-12 testing published by Ascent Filtration Testing, I had viewed the Ultra as probably the efficiency king for this application.

With First Brands in liquidation and the future of Champion/FRAM filter production uncertain, however, I no longer see the current Ultra as a dependable long-term option. Even if production returns under new ownership, there is no guarantee that it will remain the same filter.

That sent me down the rabbit hole of trying to find the next best PF66-compatible filter. The problem is that the published efficiency information is all over the place. Some manufacturers give an efficiency percentage at 20 microns, others use 25 or 30 microns, and some provide no meaningful micron-specific information at all. That makes an honest comparison based on the advertising nearly impossible.

Since I would have liked to see a comprehensive comparison myself, I started buying the filters. My eventual plan is to cut them open and compare their construction, media area, pleat consistency, valves, component dimensions, workmanship, and whatever reliable manufacturer specifications are available. I realize that a teardown cannot reveal actual filtration efficiency, but it should still tell quite a bit about how the filters are designed and built.

I initially wasn’t going to include all of the “20K” and extended-performance filters because I suspected some might prioritize capacity and service life over finer filtration. By the time I had purchased most of the others, though, I decided it would be more useful to include them and make the comparison as comprehensive as reasonably possible.

Here is what I currently have on hand:

• ACDelco PF66
• ACDelco PF66A
• ACDelco Gold Ultraguard UPF66R
• Baldwin B40162
• CarQuest Premium 95146
• CarQuest Extended Performance P95146
• FRAM Tough Guard TG12447
• FRAM Ultra XG12447
• FVP R0351
• K&N HP-1021
• Luber-finer PH10066
• MicroGard MGL10351
• MicroGard Select MSL10351
• Mobil 1 Extended Performance M1-115A
• NAPA Gold 100351
• NAPA ProFormer 2100351
• Parts Plus PH10066
• Premium Guard PG99495
• PPE MicroPure 114000650
• ProTec PXL10351
• Purolator L11424
• PurolatorONE PL11424
• PurolatorBOSS PBL11424
• Purolator 20K LX12447
• STP S45008
• STP Extended Life S45008XL
• WIX WL10351
• WIX XP WL10351XP

Still in transit:

• NAPA Platinum 6100351
• Donaldson P584944

Other filters I know about but have not yet decided whether to purchase:

• aFe Pro Guard HD 44-LF047
• Champ PH10066
• ECOGARD X11715
• ECOGARD Synthetic+ S11715
• FRAM Drive FD12447
• FRAM Extra Guard PH12447
• FRAM Force FF12447
• FRAM Titanium FS12447
• Hengst H832W
• MAHLE OC1660
• Mighty M9510
• PurolatorTECH TL11424
• Service Champ OF1424

Availability may determine whether I can obtain the remaining FRAM filters.

I have not tried to purchase every jobber or installer-grade filter. At this point, I am mainly trying to determine whether I have overlooked any significant consumer filter, unusual design, or distinct manufacturing source.

I am also aware of the PF66B and PF66C. The PF66C was not listed in the GM parts catalog for purchase. I ordered a PF66A and PF66B through GM, but they supplied two PF66As instead. The PF66A and PF66B apparently are treated as interchangeable Silver-series filters in the GM ordering system.

Is there anything important I’m missing before I consider the collection complete?

Please also let me know if I have a bad cross-reference, an incorrect or superseded part number, or an obvious duplicate being sold under another label.

Once the remaining filters arrive and I settle the inventory, I’ll make a follow-up post outlining the measurements and observations I’m considering before I start cutting them open.

Also, one date-code observation that may help others:
One useful thing I found while assembling the collection concerns the date codes on the Vietnam-made filters. Several filters share the suffix 8748, have very similar external construction, and appear to come from VAFI in Vietnam.

Based on the codes from my filters, several older Premium Guard photo examples, and a VAFI pre-shipment inspection report dated September 3, 2020 I found on the internet, the format appears to be:

YY|”M”|[last letter of month][first letter of month]|DD|”8748”

Examples:

• 25MRO18 8748 = October 18, 2025
• 25MRN25 8748 = November 25, 2025
• 25MRD19 8748 = December 19, 2025
• 26MHM31 8748 = March 31, 2026
• 26MLA14 8748 = April 14, 2026

The factory inspection report was especially helpful because it contained codes such as 20MTA30, 20MTA31, 20MRS01, and 20MRS03 immediately before a September 3, 2020 inspection. Those correspond neatly to August 30-31 and September 1-3.

The month code appears to use the last letter of the month followed by its first letter: RO for October, RN for November, RD for December, HM for March, and so forth. January and July both appear to produce YJ, so those two require context.

I have not seen this date-code format documented elsewhere, so I would be interested to know whether anyone has seen additional examples or has factory information that confirms it.

 

[GW.]

Impressive collection of filters. I look forward to all the cuts.

What you will find is the PGI made filters have the most consistent QC and overall best build quality currently. Any of the Extended drain versions will be a great Fram Ultra replacement. The Ultra hasn’t been the same since the First Brands take over anyway. I would use these PGI filters myself as an Ultra replacement.

Premium Guard Ultimate(99.5%@25, 20k rated, nylon mesh backed)

Carquest EP(99.5%@25, 20k rated, nylon mesh backed)

Napa Platinum(99%@20, 25k rated, metal wire backed)

STP Max(99.5%@25, 20k rated, metal wire backed)

 

[Lubener]

If any of those filters which you presently have will work, why would you want to purchase additional ones??

 

[martinq]

My new favourite thread. Hello, welcome and THANK YOU!

 

[ZeeOSix]

I initially wasn’t going to include all of the “20K” and extended-performance filters because I suspected some might prioritize capacity and service life over finer filtration.

That's where you have to look at the ISO efficiency rating on any filter rated for 10K to 20K miles. As @GW. showed, there are some that fit the bill of high efficiency and rated for long use ... like the Ultra was also rated.

 

[ZeeOSix]

I've save some time and money and not buy any Fram or Champ Lab made filters still out there since they are not out of business until PGI fires it back in how they see fit.

 

[ZeeOSix]

Also, one date-code observation that may help others:
One useful thing I found while assembling the collection concerns the date codes on the Vietnam-made filters. Several filters share the suffix 8748, have very similar external construction, and appear to come from VAFI in Vietnam.

Based on the codes from my filters, several older Premium Guard photo examples, and a VAFI pre-shipment inspection report dated September 3, 2020 I found on the internet, the format appears to be:

YY|”M”|[last letter of month][first letter of month]|DD|”8748”

Examples:

• 25MRO18 8748 = October 18, 2025
• 25MRN25 8748 = November 25, 2025
• 25MRD19 8748 = December 19, 2025
• 26MHM31 8748 = March 31, 2026
• 26MLA14 8748 = April 14, 2026

The factory inspection report was especially helpful because it contained codes such as 20MTA30, 20MTA31, 20MRS01, and 20MRS03 immediately before a September 3, 2020 inspection. Those correspond neatly to August 30-31 and September 1-3.

The month code appears to use the last letter of the month followed by its first letter: RO for October, RN for November, RD for December, HM for March, and so forth. January and July both appear to produce YJ, so those two require context.

I have not seen this date-code format documented elsewhere, so I would be interested to know whether anyone has seen additional examples or has factory information that confirms it.

Good info since the PGI made filter date code has always been an unknown, except for the year made. This has to be some fan of Secret Squirrel coming up with this convoluted date code format, lol.

 

[1pt21Jigs]

@GW., thanks - that gives me something specific to watch for when I compare the PGI-made filters. I already have the CarQuest EP, and I’ll pick up the NAPA Platinum tomorrow. I previously searched for a Premium Guard Ultimate and STP Max in the PF66 application but could not find either one listed. If you know of exact part numbers for this application, I’d definitely be interested.

@Lubener, fair question. Any number of the filters I already have would probably be more than adequate for my OCI. I kept buying filters because I could not find the type of broad PF66 comparison I was looking for, and I thought documenting the differences might be useful to others that were curious.

@ZeeOSix, agreed on the extended-drain filters. I initially suspected that many might trade finer efficiency for greater capacity, but I ultimately included them rather than relying on that assumption.

I understand your point about not spending more on the remaining ones given the uncertainty surrounding future production. Since several of the missing FRAM variants have been heavily discounted though, I may still pick them up mainly to document and compare the complete lineup rather than because I expect them to be long-term replacement candidates.

I’m also glad the VAFI date-code information was useful. I had not seen the full format decoded anywhere else either. That’s my best estimate of the codes, hope it stands up over time, and saves others from the mental gymnastics of decoding.

 

[ZeeOSix]

@ZeeOSix, agreed on the extended-drain filters. I initially suspected that many might trade finer efficiency for greater capacity, but I ultimately included them rather than relying on that assumption.

There are long use rated filters that are pretty low efficiency, like the Purolator Boss and the LX gold 20K filter. Before Purolator tech line stopped giving that efficiency info out not long ago, they told me both those filters are 99% @ 46 microns.

Then there are long use rated filters that are in the 99% @ 20 to 25 micron range, like all the PGI made extended filters. The Ultra was 99+% at 20u and rated for 20K miles. A high efficiency, long OCI rated filter can be made if it's done right.

The Mobil 1 extended use filter (both the Mann+Hummel made and Highline Warren made versions) is in between those extremes at 99% @ 30 microns.