The fuel filter on a Cummins ISX or X15 is the most consequential $20 in your maintenance routine. Pick the wrong one, install a "compatible" that is not actually compatible, and you can be staring at an $11,000 bill to replace six injectors before lunch on a Tuesday.
Cross-reference is not a luxury. It is the difference between a tank of bad fuel that makes a filter ugly and a tank of bad fuel that takes out the high-pressure common-rail. The wrong filter looks identical to the right filter on the parts counter. The engine does not tell you which one you put in until something fails.
This guide cross-references the four Fleetguard part numbers you will see most often on a Cummins ISX or X15: FF5776, FF5825NN, FF5791NN, and FF2200. For each, we list the Steinberg equivalent, the engine generation it fits, and the cross-references to Donaldson, Baldwin, WIX, and OEM Cummins part numbers. If your part number is not listed below, the Steinberg cross-reference search covers the full catalog.
Which Cummins ISX or X15 generation are you on?
Cummins changed configurations across model years. Before you order anything, identify which generation your engine belongs to. The wrong generation cross-reference is the most common reason buyers end up with a filter that physically threads on but does not protect the way it should.
- ISX EPA2010 (2010 to 2016 model years): primary fuel filter is Fleetguard FF5776
- ISX15 and X15 (2017 to 2019 model years): primary fuel filter is Fleetguard FF5825NN
- X15 Stage V (2020 and later, EPA Phase 2): primary fuel filter is Fleetguard FF5791NN
- All ISX and X15 generations: secondary fuel filter / water separator is Fleetguard FF2200 (also referenced as FS1212 in some Cummins service literature)
If you are not sure which generation you have, the engine serial number is the authority. Look on the dataplate on the rocker cover or the engine block. Cummins QuickServe Online accepts the ESN and returns the exact configuration. Do not guess off the truck VIN; ESN is the source of truth.
FF5776 cross-reference: ISX EPA2010 primary fuel filter
The FF5776 is the primary fuel filter for Cummins ISX engines built between 2010 and 2016 under the EPA2010 emissions standard. It threads on at the secondary filter housing on the right side of the engine on most Cascadia, Kenworth T660, and Peterbilt 386/388/389 applications.
- Fleetguard: FF5776
- Donaldson: P551313
- Baldwin: BF7674
- WIX: 33775
- Cummins OEM: 5283172
- Steinberg equivalent: search the cross-reference for current SKU
FF5825NN cross-reference: ISX15 and X15 primary, 2017 to 2019
The FF5825NN replaced the FF5776 when Cummins moved to the ISX15 and X15 nomenclature with revised fuel system architecture in 2017. It is not interchangeable with the FF5776 even though both threads on the same housing. Wrong filter for the wrong generation is the most common ordering mistake on this engine family.
- Fleetguard: FF5825NN
- Donaldson: P551422
- Baldwin: BF7965
- WIX: 33781
- Cummins OEM: 5319532
- Steinberg equivalent: FF006
FF5791NN cross-reference: X15 Stage V, 2020 and later
The FF5791NN is the primary fuel filter for the X15 Stage V (EPA Phase 2 emissions, 2020 and later). The Stage V architecture changed the filter media specification to handle higher-pressure injection events and lower fuel sulfur content. Pre-2020 filters will physically install on a Stage V housing but will not provide the filtration spec the system expects.
- Fleetguard: FF5791NN
- Donaldson: P576081
- Baldwin: BF46010
- WIX: 33784
- Cummins OEM: 5462007
- Steinberg equivalent: search the cross-reference for current SKU
FF2200 cross-reference: secondary water separator, all ISX and X15
The FF2200 (also referenced as FS1212 in Cummins service docs) is the secondary fuel filter and water separator. Unlike the primary, this part number applies across all ISX and X15 generations. Its job is to drop out free water before the fuel reaches the high-pressure pump. Skip this stage and water blows the injector tips, which is what turns a $20 filter mistake into the $11,000 repair.
- Fleetguard: FF2200 / FS1212
- Donaldson: P551150
- Baldwin: PF7977
- WIX: 33779
- Cummins OEM: 4988297
- Steinberg equivalent: FF004 or FF011 depending on configuration
Quick comparison: which filter for which engine
If you bookmark one section of this page, make it this one.
| Engine generation | Primary fuel filter | Secondary / water separator |
|---|---|---|
| ISX EPA2010 (2010 to 2016) | FF5776 | FF2200 / FS1212 |
| ISX15 / X15 (2017 to 2019) | FF5825NN | FF2200 / FS1212 |
| X15 Stage V (2020 and later) | FF5791NN | FF2200 / FS1212 |
When to replace your Cummins ISX fuel filters
Cummins recommends fuel filter replacement at every oil change interval, which on an ISX or X15 in standard service is 30,000 to 50,000 miles depending on duty cycle and oil quality.
That interval breaks in winter, in cold climates, and on contaminated fuel. One operator on TruckersReport, posting under the handle wichris, described running a Cummins X15 in winter conditions where filters that lasted 15,000 to 20,000 miles in summer plugged up at 3,000 to 4,000 miles in cold weather. In the worst week, he changed four filters in 200 miles. Cold weather thickens diesel, drops out water and waxes, and turns marginal fuel into a filter killer.
The filter will tell you what is in your fuel before the engine does. In winter, in cold climates, or after a fuel station you do not trust, inspect the primary filter every 5,000 miles even if the interval has not come up.
For the step-by-step procedure on the swap itself, including the four inspection checkpoints experienced mechanics catch and newer techs miss, see our companion guide on how to replace the fuel filter on a Cummins ISX15 / X15.
The price of getting the cross-reference wrong
There is no "compatible" filter. There is the right filter, and there is what destroyed somebody's HPFP last week.
The math, when something contaminates the high-pressure rail on a Cummins ISX or X15, is brutal and consistent. One driver on TruckersReport, OutlawW900, ended up $12,000 deep chasing a fuel pressure issue on his ISX15 that turned out to be leaking injectors. Another, posting as trenten02, was quoted $11,000 to install all six injectors after a contaminated fuel event.
The forum advice on this, from a long-running TruckersReport thread, is direct. A driver named Hanadarko was weighing whether to keep paying around $20 for a water separator filter or switch to an $8 plain fuel filter on his CAT. Another forum member, droy, replied with the math: "If you think that $12 difference of running a filter instead of a water separator/filter can add up quickly, wait until a shop hands you a bill for the R and R of 6 injectors due to water damaged tips."
That is the cross-reference question, in a sentence. The right filter is not the cheapest filter. The right filter is the one that protects the part downstream of it.
Why we maintain a live cross-reference tool
The information in this guide is accurate as of the publish date, but Cummins continues to revise part numbers, add running changes, and merge SKUs across generations. A static table in a blog post will go stale. The Steinberg cross-reference search is updated continuously and accepts any of the part numbers in this guide, plus competitor stock numbers from Donaldson, Baldwin, WIX, and OEM Cummins.
If you search a part number and the result is empty, that means we do not yet have a Steinberg equivalent for that exact reference. Submit a cross-reference request from the page and we respond within one business day with the right SKU or a recommendation if there is a better fit.
Order the right set for your engine. The Steinberg cross-reference returns the exact Steinberg SKU for any Cummins ISX or X15 fuel filter part number. If your part number does not return a result, submit a request from the page. We respond within one business day.
What we ship and how
Steinberg stocks OEM-grade fuel filters for Cummins ISX and X15 across all three engine generations in our Hodgkins, Illinois warehouse. The full engine catalog, including water separators, lube filters, and air intake for the Kenworth, Peterbilt, and Volvo cabs that house these engines, is in our Cummins ISX 15 / X15 Filters collection. Orders placed by 2 p.m. CST ship same day. NET-30 terms are available for qualified fleet accounts.
If you are running a fleet of Cummins-powered trucks and want a single point of contact for filter sourcing, email sales@steinbergus.com with your fleet size and the engine generations you operate. We respond within one business day with a tailored cross-reference list and pricing for your application.
Sources & further reading
- wichris, "Cummins X15 performance, fuel problems, filters plug up very fast", TruckersReport forum thread (winter filter-plugging case at 3,000 to 4,000 miles).
- OutlawW900, "Cummins ISX15 fuel pressure issues", TruckersReport forum thread ($12,000 fuel-pressure diagnostic case ending in leaking injectors).
- trenten02, "Cummins ISX 450 injector price", TruckersReport forum thread ($11,000 quote for six injectors after contaminated-fuel event).
- droy and Hanadarko, "Baldwin fuel filter question", TruckersReport forum thread (water-separator economics: $12 filter difference vs six-injector R&R).
- Cummins QuickServe Online (engine configuration lookup by Engine Serial Number; the source of truth for filter part-number identification across ISX EPA2010, ISX15 / X15 2017 to 2019, and X15 Stage V).
- Cummins Operation & Maintenance Manual for ISX and X15 (engine-specific service-interval and filter-specification reference; available via Cummins QuickServe Online).
Photos: cottonbro studio, Joshua Brown via Pexels.