R12T Fuel Filter Cross Reference: Every Compatible Part Number (and Three That Don't Fit)
, by iFJF Direct, 10 min reading time
The verified R12T cross-reference list — Racor S3240 / 120AT, Sierra 18-7947 / 18-7987, WIX 33583, Baldwin BF1380, Fleetguard FS19802 and more — plus the three part numbers that get wrongly listed and will not thread onto an M18 x 1.5 head.
R12T Fuel Filter Cross Reference: Every Compatible Part Number (and Three That Don't Fit)
Short answer: the R12T crosses to Racor/Parker S3240 and 120AT, Sierra 18-7947 and 18-7987, RK10222, WIX 33583 (NAPA 3583), Baldwin BF1380, Fleetguard FS19802, AC Delco TP1416, Honda 17670-ZW1-030GH, Suzuki 99105-20006 and Mallory 937812. It does not cross to Baldwin BF1258, Fleetguard FF5320 or Donaldson P551313 — those are 1-14 UN heavy-truck filters and will not thread onto an R12T head.
That last sentence is the reason this page exists. Several cross-reference lists floating around online mix heavy-truck fuel filters into the R12T family, and the mistake is expensive: you find out at the dock with a filter that won't thread on. Below is the verified list, the physical spec that decides it, and the three numbers to ignore.
The R12T family in one picture: M18 × 1.5 centre thread, NPT ZG1/4-19 ports, 10-micron spin-on element. Every compatible part number shares that centre thread — and the incompatible ones do not.
The one spec that decides everything
An R12T is not defined by its brand name — it is defined by its centre thread. Get this number right and the cross-reference list is short and unambiguous:
| Specification | R12T / R12H |
|---|---|
| Centre thread (element to head) | M18 × 1.5 |
| Inlet / outlet ports | NPT or ZG1/4-19 (four ports — two in, two out) |
| Filtration | 10 micron nominal |
| Rated flow | 15 GPH (57 LPH) |
| Bowl thread | 2-1/4–10 (standard 120A-series bowl thread) |
Anything with an M18 × 1.5 centre thread and a 120A-pattern bowl thread is a candidate. Anything with a 1-14 UN thread is a different product family entirely, no matter how similar the "fuel filter / water separator" description sounds.
The R12T cross-reference table
Verified against WIX's own catalogue data, distributor interchange tables and the published "replaces" lists on the major aftermarket listings — these are the numbers that agree with each other across independent sources:
| Brand | Part number | Notes |
|---|---|---|
| Racor / Parker | S3240 | The most common reference point |
| Racor / Parker | 120AT | 120A / 140R series element |
| Racor / Parker | 120RRAC01 / 120RRAC02 120R-RAC01 / 120R-RAC02 |
Same assembly, different catalogue formatting |
| Sierra | 18-7947 (187947) | Direct element equivalent |
| Sierra | 18-7987 | Frequently listed alongside 18-7947 |
| WIX | 33583 | WIX lists it as the element for the Racor 120A / 140R assembly — 10 micron, 15 GPH, M18 × 1.5 |
| NAPA | 3583 | NAPA Gold equivalent of WIX 33583 |
| Baldwin | BF1380 | Correct Baldwin number for this family |
| Fleetguard | FS19802 | Also seen as FS19802FLG |
| AC Delco | TP1416 | — |
| Mallory | 937812 (9-37812) | — |
| Honda Outboards | 17670-ZW1-030GH | Honda OEM number (also written 17670ZW1030GH) |
| Suzuki Outboards | 99105-20006 | Suzuki OEM number (also written 9910520006) |
| Aftermarket | RK10222 | Common in kit form |
| iFJF | R12T / R12H | This product family |
A note on how to read any cross-reference table, including this one: an interchange match means the element threads, seals and flows the same way. It does not guarantee the same micron rating. Several of the numbers above are sold in multiple ratings — WIX 33583 is 10 micron, but the same body exists as 33582 (2 micron) and 33584 (30 micron). Always confirm the micron rating as well as the part number.
Three part numbers that do NOT fit an R12T
These show up on some online cross-reference lists and they are wrong. Every one of them uses a 1-14 UN thread — a completely different, much larger pattern used on heavy-truck and construction equipment:
| Part number | What it actually is |
|---|---|
| Baldwin BF1258 | 1-14 UN, 94 mm dia., 189 mm tall — used on Case / Daewoo equipment and Cummins N14. Not compatible. |
| Fleetguard FF5320 | 1-14 UNS-2B, 93 mm dia. — a Caterpillar 1R-0750 equivalent for CAT C15 / C13 / C12 on-highway trucks. Not compatible. |
| Donaldson P551313 | Belongs to the same FF5320 / 1R-0750 group. Not compatible. |
If you have one of these in hand and you are looking at an R12T head, no adapter will bridge it. The thread diameters differ by more than 10 mm. The correct Baldwin number for this family is BF1380, and the correct Fleetguard number is FS19802.
R12H uses the same head, different element
The R12H shares the R12T's fitment — same M18 × 1.5 centre thread, same port options, same bowl threads — but uses a detachable element instead of a sealed spin-on can. That means the two are not element-interchangeable with each other, even though the housings cross to the same vehicles and equipment:
- R12T element — sealed spin-on can. Cross-references as listed above (S3240, 120AT, 18-7947, WIX 33583…).
- R12H element — bare cartridge that drops into the R12H bowl assembly. It is not a substitute for the spin-on numbers above, and the spin-on numbers are not a substitute for it.
Both housings will accept each other's plumbing — same ports, same threads — so if you are replacing a complete assembly rather than just an element, either one drops in.
How to verify any cross-reference in two minutes
Don't trust a list (including this one) over the part in your hand. Three checks settle it:
- Measure the centre thread. An R12T-pattern element has an M18 × 1.5 thread. If the number you're comparing claims 1-14 UN, stop — wrong family.
- Measure the can diameter. Around 76 mm (3 in) for this family. A 93–94 mm can is a heavy-truck filter.
- Check the micron rating, not just the number. 10 micron for the R12T. Same-body variants exist at 2 and 30 micron and will physically fit while filtering wrong.
If all three line up, it fits. If any one doesn't, it doesn't — and no adapter makes a 1-14 thread into an M18 × 1.5.
Frequently Asked Questions
Is the R12T the same as a Racor 120AT?
It's an aftermarket replacement for it. Same M18 × 1.5 centre thread, same 120A-pattern bowl thread, same port options, same 15 GPH / 10 micron class — so it fits the same applications and accepts the same elements. It is not a Parker-manufactured part, and interchange promises fitment, not identical media construction.
Will a WIX 33583 fit my R12T housing?
Yes. WIX lists the 33583 as the element for the Racor 120A / 140R assembly, at M18 × 1.5 and 15 GPH — the same family the R12T belongs to. It is a direct fit for the element position.
Someone told me Baldwin BF1258 works. Does it?
No. BF1258 is a 1-14 UN heavy-duty filter for Case/Daewoo equipment and Cummins N14 engines. The thread is more than 10 mm larger than an M18 × 1.5 and it will not start onto an R12T head. The correct Baldwin cross is BF1380.
Do S3213 and S3227 elements fit the R12T?
Treat these with caution. S3213 and S3227 belong to the outboard-oriented family with a different centre thread, and they appear on R12T listings mainly because sellers stack related keywords. Verify by measuring the centre thread before ordering.
My engine uses a 120AT housing. Can I just buy the R12T element?
Yes — that's the most common use case. The element thread and bowl pattern match the 120AT series, so an R12T element threads onto an existing 120AT-style head. Measure once to confirm your head is the M18 × 1.5 pattern and you're set.
iFJF R12T Fuel Filter Water Separator — Complete Combo Kit
M18 × 1.5 centre thread, NPT ZG1/4-19 ports, 10-micron spin-on element, clear nylon bowl with self-venting drain. Replaces Racor S3240 / 120AT, Sierra 18-7947 / 18-7987, RK10222 and the other numbers listed above.
Shop the R12T Kit →🛒 Parts Used in This Guide
- R12T Complete Combo Kit — head, element, bowl, four brass fittings, two port plugs
- R12T Replacement Element, 10 micron — the direct-fit element for 120AT / S3240-style heads
- R12T Filter Base / Head — accepts any standard 120AT-pattern spin-on element
- R12H Aluminium Upgrade Combo — same fitment, detachable replaceable element
Related Reading
- How Often Should You Drain a Fuel-Water Separator? The R12T Draining & Maintenance Guide — draining intervals, reading the bowl, diesel bug and the ABYC / USCG rules.
- R12T Marine Fuel Filter Installation Guide — siting, thread identification, torque and priming.
- R12T vs R12H: Real Customer Review + Installation Guide — which variant to fit.
Not sure which element your head takes? Send us a photo of the existing filter or the housing thread and we'll confirm the correct part before you order.
Cross-reference numbers are provided for identification purposes only. OEM and brand names are trademarks of their respective owners and are used here solely to indicate fitment. Always verify thread size and micron rating against the part you are replacing.
