Amsoil Oil Filter Cross Reference: EaO and EaBP Numbers Explained

An AMSOIL oil filter number is a service rating plus an application code. EA15K filters are rated for 15,000 miles, EAO filters for 25,000, and EaBP is the bypass line. WIX's lookup crosses every Ea number I tried, and since early 2026 AMSOIL itself names WIX as the stand-in when its own filters run short.

AMSOIL Oil Filter Cross Reference Chart

The WIX column comes from WIX's competitor lookup, which indexes AMSOIL numbers directly. The application column is AMSOIL's own, from its filter specifications sheet, shortened to the car and truck makes.

EA15K Filters (15,000 Miles)

EAO Filters (25,000 Miles)

WIX returns its XP version alongside almost every standard part, so EAO11 crosses to both the 51372 and the 51372XP. The XP is the synthetic-media grade; the standard WIX is cellulose.

K&N's cross-reference index has no AMSOIL page at all, so for most of these rows WIX is the only manufacturer cross that exists. Where a row also lands on a number this site has traced through a third brand, it agrees: EAO11 and the Motorcraft FL-820S both cross to the 51372, and EAO98 and the FL-2124-S both cross to the 57151.

AMSOIL publishes no cross reference of its own outside its store's lookup tool. WIX's lookup is the only manufacturer document that maps an AMSOIL number to another brand.

What Do EA15K, EAO and EaBP Mean?

The prefix is a service rating, not a size or a filter type. AMSOIL's data sheet for its oil filters rates EA15K filters for 15,000 miles or one year in normal or severe service, and EAO filters for 25,000 miles or one year in normal service, dropping to 15,000 miles in severe service.

Those intervals only apply with AMSOIL synthetic motor oil. With any other oil, the same sheet says to change the filter at the vehicle manufacturer's interval, and it also says to change it at every oil change.

Why Some Filters Are EA15K and Others EAO

AMSOIL does not say. On its own specifications sheet, though, every EAO spin-on is either taller or wider than every EA15K spin-on: the tallest EA15K can is 3.53 in, the shortest EAO is 3.10 in tall but 3.79 in wide, and every car and truck cartridge on the sheet is EA15K.

So the longer rating sits on the bigger cans. Whether that is the reason is my reading of the sheet, not something AMSOIL has published.

What EaBP Means

EaBP is AMSOIL's bypass filter, which takes a small share of oil flow through a much finer element alongside the full-flow filter. AMSOIL's store page for its bypass kit rates the EaBP90 to 60,000 miles, the EaBP100 to 70,000 and the EaBP110 to 80,000, each capped at two years.

WIX's lookup returns the WL11042 for the EaBP90 and nothing for the EaBP100 or EaBP110. AMSOIL recommended that same WL11042 during its 2026 shortage, but one owner who called both companies reported that neither would share filtration specs, and AMSOIL would not confirm the two meet the same spec.

What Efficiency Does AMSOIL Publish?

AMSOIL's current data sheet, coded G2192 and dated December 2025, claims 99% efficiency at 20 microns under ISO 4548-12, the multi-pass test. It gives that one figure for the whole line, with no part number named as the one tested.

The October 2016 edition of the same sheet printed 98.7% at 20 microns, from test results dated February 2011. The 2025 edition drops that test chart and gives no new test date, so I could not find what testing moved the figure from 98.7 to 99.

The same sheet describes resin-free full synthetic media pleated with a rigid mesh backing, a silicone anti-drainback valve and nitrile gaskets. It publishes no burst pressure and no capacity figure.

Do AMSOIL and WIX Agree on the Bypass Setting?

Not often. AMSOIL's specifications sheet lists a bypass relief valve range for every spin-on, and for most of them it is the same 20 to 30 psi. WIX's catalogue gives a single opening pressure per part, and for the filters it crosses to those AMSOIL numbers, the figures are mostly far lower.

WIX prints its figure without a unit. Read as bar, the values convert to the psi figures shown, and the 1.516 setting matches the 22 psi bypass GM specifies for the PF63 family.

The gap runs both ways. Three AMSOIL filters list a range whose bottom is more than double the WIX setting, while the EAO11 lists a range that tops out below the 22 psi WIX gives its 51372. Only the EAO17 range contains the WIX figure.

A bypass valve that opens later keeps oil going through the media longer; one that opens sooner protects oil flow when the filter is cold or loaded. The engine maker picked a number for a reason, and the two documents here disagree on what that number is.

I cannot tell from the documents which is right for a given engine. AMSOIL's sheet uses one range across filters for very different engines, which reads like a line value rather than a per-part setting, but AMSOIL does not say so.

The EAO17 Height Problem

AMSOIL lists the EAO17 for both Ford and GM, and gives its height as 4.09 in. That is exactly the 103.9 mm of the WIX 57502, the Ford FL-500S equivalent.

WIX's lookup sends the EAO17 to the WL10255 instead, the GM PF63 equivalent, which is 113.6 mm or 4.47 in tall. A Ford owner following WIX's cross from an EAO17 gets a can almost 10 mm taller than the filter AMSOIL describes.

On a GM engine that is the right part. On a Ford, the 57502 is the WIX filter that matches both AMSOIL's dimensions and Ford's own number, so check clearance before fitting the taller one.

Who Makes AMSOIL Oil Filters?

AMSOIL does not name a manufacturer. On 27 February 2026 it told dealers that one of its filter manufacturing partners had unexpectedly halted production of most filters, including AMSOIL Oil Filters, and that as each filter ran out it would recommend the appropriate WIX replacement.

AMSOIL called the WIX supply temporary. Owners on the same forum have long attributed the EA15K line to Champion Laboratories, part of First Brands Group, which filed for Chapter 11 in September 2025, but neither AMSOIL nor Champion has confirmed it.

Redesigned AMSOIL filters began arriving in August 2026. Owners comparing the new EA15K02 report plastic end caps, thinner media and no wire mesh backing, and guess at Premium Guard or MANN+HUMMEL as the new maker without evidence for either.

A WIX Filter From AMSOIL Is Not Covered by AMSOIL's Warranty

AMSOIL's limited warranty for filters excludes "Non-AMSOIL brand filters, including those sold by AMSOIL." A WIX filter bought from AMSOIL during the shortage sits outside that warranty, whatever the box it shipped in.

The warranty also covers an AMSOIL filter only up to the service life AMSOIL or the vehicle maker recommends in writing, so the EAO 25,000-mile rating only counts with AMSOIL oil.

What Owners Report About AMSOIL Filters

The most repeated complaint concerns the bypass valve. In a 2024 to 2025 thread of cut-open EA15K filters, owners flagged a ruffled bypass leaf spring stamping, which they tie to a run of leaky bypass valves on Champion-built filters, though the poster of that cut-open said his looked symmetrical from the other side.

These are a few owners' photographs and readings of them, not a test or an AMSOIL bulletin. They are worth knowing because the redesigned 2026 filter no longer matches the mesh-backed construction AMSOIL's December 2025 data sheet still describes.

Frequently Asked Questions

What is the WIX equivalent of the AMSOIL EAO17?

WIX's lookup returns the WL10255 and WL10255XP for the EAO17. That is the GM PF63 equivalent, 4.47 in tall. AMSOIL lists the EAO17 at 4.09 in, which matches the Ford 57502 instead, so on a Ford, the 57502 is the closer match to the filter AMSOIL describes.

Is an AMSOIL EA15K the same filter as an EAO?

No. They are different part numbers for different applications, not two grades of one filter. AMSOIL rates EA15K filters for 15,000 miles and EAO filters for 25,000 in normal service, and on AMSOIL's own sheet every EAO spin-on is a larger can than every EA15K spin-on.

Who makes AMSOIL oil filters now?

AMSOIL has not said. In February 2026 it reported that a manufacturing partner had halted production and supplied WIX filters as a temporary replacement. Redesigned AMSOIL filters reached owners from August 2026, and their maker has not been confirmed by AMSOIL or by any supplier.

Can I use a WIX filter instead of an AMSOIL filter?

AMSOIL itself recommended WIX replacements during its 2026 shortage, so the cross is AMSOIL's own position. Check the bypass setting and height for your engine first, since the two brands publish different figures for several pairs, and note that AMSOIL's filter warranty excludes non-AMSOIL filters.

Does AMSOIL publish a micron rating?

Yes: 99% efficiency at 20 microns under ISO 4548-12 for the whole Ea line, with no test date. An earlier edition of the same data sheet gave 98.7% at 20 microns from February 2011 tests. AMSOIL publishes no burst or capacity figure.

Where to Start

Find your AMSOIL number in the charts above, then open the WIX cross's catalogue page and compare thread, height and bypass setting against the filter your engine came with. Where AMSOIL and WIX disagree, the vehicle maker's own part number decides.