Fleetguard FS1022 fuel/water separator
Seller-written product guide for the Fleetguard FS1022 spin-on diesel fuel/water separator. Read the published specifications, cross-references, and service notes below, then match the stamp on your filter head before you order. The listing price and purchase links appear after this introduction.
What this part is
The Fleetguard FS1022 is a spin-on diesel fuel/water separator sold here as a replacement element when the removed can, OEM part number, or a listed cross-reference matches FS1022. It is a fuel-system service item for free water and particulate matter that reach the separator sump. It is not a crankcase oil filter, not a coolant spin-on, and not a substitute for diagnosing tank contamination, transfer-pump wear, or injection faults.
Use this number when the filter head thread, overall length, standpipe requirement, and printed stamp already point to FS1022 or to one of the interchange numbers listed later on this page. If those checks do not line up, identify the correct separator for that module before opening a carton.
Published specifications
The following dimensions and media data appear on Cummins Filtration product literature for FS1022 (Fuel/Water Sep Spin-On). Confirm each value against the filter head and the part you remove. A wrong thread or a missing standpipe will not seal correctly or can starve the supply pump.
- Style: spin-on fuel/water separator
- Thread: 1-14 UNS-2B
- Overall length: 238.30 mm (9.38 in)
- Media: StrataPore
- Micron rating (SAE J1985): 10 micron
- Standpipe: yes
Distributor literature for the same part commonly also lists an outside diameter near 93.83 mm (about 3.69 in). When you compare cans on a bench, check OD, height, drain orientation, and whether the module expects a standpipe. Thread class 1-14 UNS-2B is specific; do not force a can with a different pitch or diameter onto the head.
StrataPore media at a 10 micron SAE J1985 rating is the published filtration level on the product sheet. Field duty still depends on fuel quality, drain discipline, and the interval in the engine or chassis maintenance manual for your VIN.
Verified cross-references
Interchange numbers commonly listed for FS1022 include the following. Cross lists help when a purchase order or removed can shows another brand. They do not replace a physical check of thread, length, standpipe, and drain layout.
- Cummins: 3800394, 3944269, 3945066
- Donaldson: P551122, P551022
- Baldwin / Parker: BF1272-SPS (also listed as BF1272SP / BF1272SPS)
- WIX: 33422
Donaldson P551122 and P551022 both appear on distributor cross-reference lists for FS1022 (Spareto and KLM Performance listings checked for this guide). Treat either Donaldson number as a catalog cross only: still verify the stamp and dimensions on the unit you remove. Baldwin BF1272-SPS family spellings vary by catalog punctuation; the interchange set is the same.
Verify part number / vehicle application before ordering (check your engine's filter head and existing part number).
How to verify the part number before you order
Use a short checklist so the carton you open matches the head on the truck:
- Photograph the printed number on the removed separator from two angles. Wipe mud or oil so the stamp is readable.
- Read the OEM or Fleetguard number. If it says FS1022, you already have a direct match. If it shows one of the Cummins numbers above (3800394, 3944269, or 3945066), or Donaldson P551122 / P551022, Baldwin BF1272-SPS, or WIX 33422, compare that cross against this listing.
- Confirm thread 1-14 UNS-2B on the head. Do not rely on memory of a previous PM; mid-year module changes happen.
- Measure overall length against 9.38 in (238.30 mm) when the old can is available. A shorter or taller can may share a family look but seat differently.
- Confirm the module expects a standpipe. FS1022 literature lists standpipe: yes. Installing a no-standpipe can on a standpipe head, or the reverse, can cause air leaks or fuel starvation.
- Compare drain petcock location and bowl layout to the removed unit so hoses and sensor ports still reach after install.
If the old separator is missing, send photos of the filter head and the VIN to support@aonetruckauto.com, or use the Contact Us form. We do not publish a make/model/year fitment table for FS1022 on this page; application is confirmed by stamp, thread, length, and standpipe.
Service and change-interval guidance
Change intervals for fuel/water separators are set by the engine maker, the chassis maker, and the duty cycle in the maintenance manual for that serial number. This guide does not invent a universal mileage or hour interval for FS1022. Use the OEM or engine manual first. Fleet fuel quality, tank housekeeping, and humidity often shorten separator life relative to a laboratory schedule.
Shop practice often treats separator service as part of scheduled fuel-system PM, then shortens the interval when trucks fuel from high-turnover lanes with known water, when drain samples show heavy free water between changes, or when restriction indicators appear after wet weather. Those are operational signals, not a substitute for the published OEM chart.
List the separator as its own work-order line. Record the removed stamp, the installed stamp, and drain-sample water volume. If water returns quickly after a fresh FS1022 install, inspect the tank and supply lines; a new separator will not fix a contaminated tank.
Draining water
Free water is denser than diesel and collects in the separator sump when the module allows gravity separation. Draining is a routine inspection step, not only a response to a dashboard lamp. Park on level ground, shut the engine down, and relieve fuel-system pressure using the procedure in the engine or chassis manual for that fuel module.
Place a clear container under the drain. Open the petcock slowly and capture the fluid. Clear diesel at the end of the drain is normal after free water exits. Cloudy emulsion, algae slime, or metallic glitter should be logged and investigated upstream. Close the petcock firmly and wipe the valve seat so a seep is visible later.
Dispose of drained fluid according to local environmental rules. Do not return drained water to the tank. Drain frequency between element changes depends on fuel volume and water load. If no one remembers the last drain, schedule both a drain inspection and a planned element change. A loose petcock will drip after road vibration even when the spin-on gasket is sealed.
Priming after service
Replacing a spin-on fuel/water separator opens the supply path to air. Priming restores solid fuel to the pump and injectors according to the module procedure for your engine. Follow the OEM priming steps for that chassis: hand primer, electric lift pump cycle, or specified key-on pump run times.
Do not fill an FS1022 spin-on with engine oil before install. That oil-filter habit does not belong on a fuel/water separator. If the service literature allows wetting the gasket with clean diesel, use clean diesel only.
After priming, idle the engine and watch for leaks at the gasket, drain valve, and any sensor ports. Recheck after a short road test. If the engine stalls with air in the lines, repeat the OEM prime sequence and confirm the standpipe and gasket seated correctly.
Installation notes
Park safely, chock wheels when required by shop policy, and relieve fuel pressure per the engine maker’s procedure before spinning the old can off. Support the separator so residual fuel drains into a catch pan. Compare the printed number on the old element with FS1022 or the cross list on this page before discarding the old can.
Clean the sealing surface on the head. Remove old gasket material without gouging the seat. Inspect the head threads. Install the new FS1022 hand-tight until the gasket contacts the seat, then apply the additional turn or torque value specified by the filter or engine maker for that spin-on. Over-tightening can crush the gasket; under-tightening can seep under vibration.
Confirm the drain petcock is closed before priming. Route any sensor connectors that were unplugged for clearance. After the idle leak check, wipe the can dry so a later seep is obvious. Document the installed part number on the work order. Note drain orientation before removal so the new can’s petcock remains reachable; do not block the drain or a water-in-fuel sensor port the module uses.
Price and how to buy
We list Fleetguard FS1022 for $44.80 each in U.S. dollars (SKU FLG-FS1022). Sales tax is added where required. Shipping is quoted for your U.S. address and approved by you before the carrier is booked. Payment is through PayPal to A-One Truck Auto (HEAVY TRUCK PARTS, INC.). We are the seller on this page; we do not collect a commission from Fleetguard for publishing this guide.
Open the product page to add the separator to your cart or to pay for a single unit through PayPal. Companion lube or coolant filters are separate SKUs with their own stamps and must be verified independently. Listed ship weight for this separator is 2.8 lb on the product card, which helps when you estimate parcel shipping separate from heavy cast assemblies.
Policies and contact
Seller: HEAVY TRUCK PARTS, INC., 3290 N.W. 36th Street, Miami, FL 33142. Email: support@aonetruckauto.com.
Read Privacy Policy, Shipping policy, Returns and refunds, and Terms of Sale before you pay. Use Contact Us for fitment questions with a photo of the old filter and your VIN. Filters must be returned unopened if they are unused; see the refund policy for inspection and PayPal refund timing.