Motorcraft Oil Filter Cross Reference (FL and FL-S Numbers Explained)

A Motorcraft FL number is Ford's retail name for an oil filter, and each one maps to a Ford service number, such as AA5Z-6714-A for the FL-500S. The S suffix lines up with Motorcraft's silicone anti-drainback valve. To cross a Motorcraft filter, look up the FL or Ford number, then confirm thread, height and bypass setting.

Motorcraft Oil Filter Cross Reference Chart

These are the Motorcraft oil filters most Ford, Lincoln and Mercury owners will meet. The WIX column comes from WIX's interchange lookup, which accepts Motorcraft numbers directly, and the K&N column from K&N's Motorcraft cross-reference index. The Ford numbers are the ones Ford prints beside each filter on its own Motorcraft product pages.

The FL-910S row is worth a second look. Its WIX equivalent is the WIX 51348, one of the most widely shared filter sizes in the catalogue, so the FL-910S box and a filter sold for a Toyota or a Mazda can be the same can.

The FL-820S row lands on the WIX 51372, which makes it the same filter as the NAPA Gold 1372 and covers Ford, Lincoln and Mercury V6, V8 and V10 gasoline engines from 1991 through 2014.

A Motorcraft number and a Ford number name the same filter. Aftermarket catalogues index the Ford number, which is why it crosses more reliably than the FL number does.

What Do FL, S and A Mean in a Motorcraft Number?

The letters at the front are a filter type code. K&N's index sorts 257 Motorcraft numbers by type, and the pattern holds across all of them: FL is oil, FA is engine air, FG is fuel and FP is cabin air.

FL covers cartridges as well as spin-on cans. Ford sells the FL-2062A as an "element and gasket kit", and WIX lists its equivalent as an element 49 mm across with no thread. The FL prefix tells you it filters oil, not how it mounts.

What the S Suffix Means

Ford publishes no key to the suffix letters. The S lines up with the silicone anti-drainback valve: Ford's Motorcraft oil filter pages carry the line "Anti-drain back valves made of silicone provide greater cold and heat resistance", and when the FL-910 was superseded in 2010, owners tracking the change reported that the new FL-910S added a silicone anti-drainback valve.

The reverse does not hold. The same silicone sentence appears on the pages for the FL-839 and the FL-2062A, which carry no S, so a missing S does not prove a filter has a nitrile valve.

What the A Suffix and a B12 Ending Mean

An A marks a later revision, and Ford does not say what changed. K&N's index lists the FL-400, FL-400A and FL-400S as three separate numbers, and the FL-810, FL-810A and FL-810S the same way, so an A and an S can both exist on one base number.

Ford also sells some filters under a second listing ending in B12, and that listing carries its own Ford number. The FL-400S is E4FZ-6731-AB and the FL-400SB12 is E4FZ-6731-BB, and the FL-820SB12 is F1AZ-6731-BE against the FL-820S's F1AZ-6731-BD.

So a Ford number one letter off from the one on your box is not automatically a different filter. Check whether it belongs to the B12 listing first.

How Motorcraft Numbers Relate to Ford Part Numbers

A Ford service number has three parts: a prefix, a basic number and a suffix. In the prefix, the fourth character names the part source, with Z for a Ford division service part and Y for a Lincoln-Mercury one. The FL-839, for example, carries F3XY-6731-A, whose Y marks a Lincoln-Mercury service part.

The basic number is the part type. On Ford's oil filters it is 6714 or 6731, and Ford uses both on ordinary spin-on cans: the FL-500S is AA5Z-6714-A and the FL-910S is BE8Z-6731-AB. The letters after the second dash are the revision.

The first two characters of older prefixes date the design, with the first letter giving the decade and the digit the year. F1AZ, the FL-820S prefix, decodes to 1991, which matches the first model years the filter covers. E4FZ, the FL-400S prefix, decodes to 1984.

Why the Ford Number Crosses Better

Aftermarket catalogues are indexed by vehicle maker numbers, not by Motorcraft retail numbers. WIX's catalogue page for the 57502 lists AA5Z-6714-A in its OE-Numbers block, which is a cross WIX stands behind on its own data rather than a chart's say-so.

So if a box, a receipt or a parts diagram gives you only the Ford number, search that. It is the number every serious catalogue, WIX's included, was built around.

Can One Motorcraft Filter Replace Another?

Not on thread alone. Two pairs of Motorcraft filters share a thread and still differ in ways that matter, and WIX's catalogue pages for their equivalents show exactly where.

The FL-910S and FL-400S thread onto the same 3/4-16 stud with the same can diameter, but the FL-400S is 36 mm taller and its bypass valve opens at twice the pressure. Fit the shorter one where the taller one belongs and the bypass opens at half the pressure difference, sending oil past the media sooner than the engine was specified for.

The FL-500S and FL-820S share an M22x1.5 thread and the same 22 psi bypass setting, but the FL-820S is 18.5 mm wider. Whether the narrower FL-500S has the clearance and gasket seat to stand in for it is a question Ford does not answer: it lists the two as separate parts for separate engines and publishes no interchange between them.

Same thread is where a Motorcraft cross starts, not where it ends. Height, diameter and bypass setting all have to match the number Ford lists for your engine.

What Efficiency Does Motorcraft Publish?

One figure, for the whole line. Ford's Motorcraft product pages state "80% efficiency on particles 20 microns and larger", and the identical sentence appears on the FL-400S, FL-500S, FL-820S, FL-910S, FL-839 and FL-2062A pages, so it describes the range, not any one filter.

Ford names no test standard beside it and publishes no bypass pressure, burst rating or capacity figure for the box. That 80% sits well below the 99% figures aftermarket brands print, but efficiency numbers only compare when the test method and particle size match, and Ford gives you neither.

The WIX spin-on equivalents publish more. Each of their catalogue pages lists a bypass opening pressure and a nominal 21 micron rating, which is the practical reason to read a Motorcraft filter's specifications through its WIX cross.

Who Makes Motorcraft Oil Filters?

Ford does not name a supplier on any Motorcraft page. Owners who cut these filters open have tied them to Purolator for years, and Purolator has been part of MANN+HUMMEL since the German company took over the Purolator Filters joint venture from Bosch at the start of 2020.

That puts Motorcraft, WIX and Purolator under one parent if the attribution is right, but neither Ford nor MANN+HUMMEL has said so in a published document. Treat it as well-supported owner knowledge rather than a confirmed supply contract.

Superseded Motorcraft Numbers

Motorcraft numbers change more often than the boxes on store shelves suggest. The FL-910 became the FL-910S in 2010, and on the Super Duty diesel the FL-2051-S was superseded by the FL-2124-S, a change most buying guides still miss.

When a cross-reference chart and Ford disagree on a number, the chart is usually one supersession behind. Look the current number up before you buy rather than matching the old box.

What Owners Report About the FL-820S

The FL-820S draws more torn-media reports than any other Motorcraft number. In one 2019 case, an F-350 owner opened an FL-820S after about 2,500 miles and found the dome end cap had come away from the adhesive and a pleat torn along both sides.

It is not a universal result. A 2026 cut-open of an FL-820S that ran 7,094 miles on a 4.6 Mustang GT found the media intact and the silicone anti-drainback valve starting to tear but not through. These are owner anecdotes, not a Ford bulletin, but they are consistent enough to justify cutting one open if you run long intervals.

Frequently Asked Questions

What is the WIX equivalent of the Motorcraft FL-500S?

WIX lists the 57502 and the 57502XP against the Motorcraft FL-500S, and its 57502 catalogue page carries Ford's own number for the filter, AA5Z-6714-A, in its OE list. Both are spin-on filters with an M22x1.5 thread and a bypass valve that opens at 1.516 bar, about 22 psi.

Is the Motorcraft FL-910S the same as a WIX 51348?

Yes. WIX's interchange lookup returns the 51348 and 51348XP for the FL-910S, and K&N returns its SO-1002. The 51348 is a 3/4-16 thread filter 74.2 mm wide and 86.5 mm tall, a size shared across many Ford, Mazda and Toyota four-cylinder engines.

What does the S mean on a Motorcraft oil filter?

Ford publishes no definition, but the S lines up with a silicone anti-drainback valve. The FL-910S replaced the FL-910 in 2010 with a silicone valve added. Some numbers without an S, such as the FL-2062A, also carry silicone valves, so the letter is a revision marker rather than a complete specification.

Can I use an FL-500S instead of an FL-820S?

They share an M22x1.5 thread and a 22 psi bypass setting, but the FL-500S is 18.5 mm narrower and 6.5 mm taller, and Ford does not list it as a substitute. Use the number Ford lists for your engine, and only substitute after confirming clearance and gasket fit.

Are Motorcraft oil filters made by Purolator?

Ford does not say. Owners have long attributed Motorcraft oil filters to Purolator, which has been owned outright by MANN+HUMMEL since 2020, the same group that owns WIX. No Ford or MANN+HUMMEL document confirms the supply arrangement, so treat it as strong owner knowledge rather than fact.

Where to Start

Find the FL number on your current filter or the Ford number in your owner's manual, run it through WIX's or K&N's Motorcraft lookup, then compare thread, height and bypass setting on the equivalent's catalogue page. If those three match the filter Ford lists for your engine, the brand on the box is your choice.