FS1022 Fuel/Water Separator

Separating free water from diesel

Water in underground tanks and condensation in saddle tanks reach the fuel module as free liquid, not just dissolved moisture. Fleetguard builds this fuel/water separator so linehaul shops can drain collected water before it moves toward the supply pump. The spin-on style housing includes a drain path for free water while the media handles particulate loading typical of ISX and X15 operation.

Listed price is $44.80 USD before tax. Ship weight is 2.8 lb on the product card. Those figures help fleet buyers estimate parcel orders separate from heavy cast-head fuel assemblies.

This is a fuel/water separator service item. It does not replace crankcase oil filters, coolant spin-ons, or air dryer cartridges. Keep PM lines distinct on work orders.

Drain petcock discipline

The drain feature is for free water that collects in the bowl or sump area per the module design. Technicians should drain into a clear container during scheduled inspections, not only when a lamp appears. Water volume tells you about tank housekeeping and upstream separator health.

After draining, inspect for algae slime or metallic glitter that points to tank corrosion or pump wear upstream. Log what you see; fuel problems repeat until the source is fixed.

Cascadia, 579, T680 with Cummins ISX and X15

Fitment rows on this page focus on Freightliner Cascadia, Peterbilt 579, and Kenworth T680 tractors equipped with Cummins ISX or X15 engines—the common western and long-haul combinations where this separator appears in PM guides. Treat the table as guidance, not a fit guarantee.

Confirm the stamp on the removed separator, engine data, and VIN build information before install. Mid-year module changes can alter drain valve orientation or can height even when the engine family matches. Verify fitment by stamp and VIN; we do not warrant compatibility from model names alone.

Send stamp photos and VIN to support@aonetruckauto.com when the old unit is lost. The contact form works for fleet documentation trails. Cross-check candidates in the fitment guide when you maintain mixed brands in one terminal.

When to service the separator

Separator service intervals often track fuel filter PM but may shorten when trucks fuel from high-turnover lanes with known water issues. Restriction lamps, slow cranking after sit time, and white smoke bursts can involve water emulsion—not always the separator alone, but draining and replacing loaded media is the controlled first step.

Do not ignore a full water drain indication until the next oil change. Water at the pump side accelerates wear and can disturb injection timing sensors on modern engines.

• Drain with engine off and pressure relieved per module instructions.
• Capture drained fluid for disposal according to environmental rules.
• Replace O-rings and gaskets that do not rebound when compressed.

FS1022 on the shop bench

If your PO references Fleetguard FS1022, compare the can height and drain location to the removed unit before opening the box. SKU the cart listing is how this separator appears in cart and PayPal lines.

Install without confusing oil service steps

Fuel/water separator service uses fuel-system priming and leak checks, not crankcase oil filter steps. Do not apply lube-filter assumptions such as filling a spin-on with engine oil. Follow the Cummins and chassis fuel module chart for your VIN, including approved seal lubricants for diesel contact.

Prime the supply side after cartridge change when the procedure requires it. Run idle, inspect the drain valve seat for seepage, and verify lamp status after a short road test if monitors exist.

Storage and seasonal operations

Winter terminals see more free water from temperature swings. Stock separators where the warehouse stays dry; media absorbs humidity if cartons sit open. At 2.8 lb per unit, separators fit PM kits alongside primary fuel spin-ons without freight class jumps on small orders.

Returns and shipping awareness

Read returns and refunds before you break seals on emergency orders. Unused-item rules and opened fuel component policies apply to separators the same as other fuel hardware.

Packaging and delivery options are documented on the shipping policy. Choose the service level that matches your downtime window without assuming expedited language that this page does not state.

Terminal buyer notes

Regional managers often pair separator changes with tank sump polishing schedules. Document drain volume after each change so purchasing can adjust interval stock. PayPal checkout reflects unit price times quantity with capture confirmation on success.

Water volume logs for purchasing

Write the drained water volume on the work order after each separator service. A sudden jump after a bulk fuel delivery points at the supplier tank, not at the separator brand on the truck.

Algae films on the drain cup deserve a tank sump polish before the next long haul. Replacing the separator alone while leaving sludge in the saddle tank returns the same wet drain a week later.

Cold mornings that gel diesel also concentrate water at the bottom of tanks. Schedule drain checks on the first idle after overnight sits in freezing yards, not only at scheduled PM miles.

Delivery methods and packaging notes live on the shipping policy. Unused-item rules are under returns and refunds. Reach us at support@aonetruckauto.com or the contact form.

A-One Truck Auto is operated by HEAVY TRUCK PARTS, INC. Manufacturer names indicate fitment language only.