The 2021 Freightliner FL has 9 cooling system parts with verified fitment on this page — 1 part type and 2 brands, covering all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged). Each part includes a manufacturer part number and application notes.
The cooling system system on the 2021 Freightliner FL keeps operating temperature in the narrow band the engine was designed for, from radiator and water pump to thermostat and hoses. Every listed part is Coolant / Antifreeze.
The 2021 Freightliner FL was sold with 3 engines. All 9 parts on this page fit every engine.
The most listed brands for 2021 Freightliner FL cooling system parts are PRESTONE (7 parts) and PEAK (2 parts). Quality grades include Heavy Duty, Premium and Compatible With All Colors.
2 parts on this 2021 Freightliner FL page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including PRESTONE AF3100 (Coolant / Antifreeze) and PRESTONE AF2100 (Coolant / Antifreeze). Click any part number to see every vehicle that part fits.
Coolant / Antifreeze
Compatible With All Colors
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Fits: all 2021 FL engines | AF3055 | 🇲🇽 MX | Prime YellowAll Vehicles | View on Amazon |
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Popular Fits: all 2021 FL engines | AF3100 | 🇲🇽 MX | Prime Yellow - All VehiclesExtended Life | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PEAK Fits: all 2021 FL engines | FCA1GAL | 🇲🇽 MX | Fleet Charge1 Gallon | View on Amazon |
| PEAK Fits: all 2021 FL engines | FXA1GAL | 🇲🇽 MX | Final Charge Global1 Gallon | View on Amazon |
| PRESTONE Fits: all 2021 FL engines | AFC10000 | 🇲🇽 MX | Command ESi PrechargedPurple | View on Amazon |
| PRESTONE Fits: all 2021 FL engines | AFC13000 | 🇲🇽 MX | Command COR-Guard Nitrite Free-Noat Extended Life CoolantRed | View on Amazon |
| PRESTONE Fits: all 2021 FL engines | AFC12100 | 🇲🇽 MX | Command Nitrite Free Extended Life CoolantYellow Nitrite Free OAT | View on Amazon |
Premium
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Popular Fits: all 2021 FL engines | AF2100 | 🇲🇽 MX | All Vehicles10yr/300k mi | View on Amazon |
| PRESTONE Fits: all 2021 FL engines | AFMAX | 🇲🇽 MX | Max Universal1 Gallon | View on Amazon |
This table covers the engine coolants and antifreeze formulations specified for this cooling system. Typical signs include a rising temperature gauge, rusty or sludged coolant, or a heater that blows cold. Use the chemistry named in the notes. Mixing silicate, OAT and HOAT formulas can gel in the radiator.
9 Coolant / Antifreeze parts for the 2021 Freightliner FL come from 2 brands — PRESTONE and PEAK. The "Popular" part is PRESTONE AF3100. Every part fits all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged).
In the Compatible With All Colors grade, PRESTONE supplies 1 part: grouped under the catalog's "Compatible With All Colors" designation — the notes column spells out what sets them apart. A representative part number is PRESTONE AF3055.
The Economy section lists 1 option from PRESTONE — the catalog's value-priced group. PRESTONE AF3100 is listed in this group.
In the Heavy Duty grade, PRESTONE and PEAK supply 5 parts: rated for severe service. A representative part number is PEAK FCA1GAL.
In the Premium grade, PRESTONE supplies 2 parts: a step above OE specification in materials, tolerances or warranty terms. A representative part number is PRESTONE AF2100.
Listed part numbers: PRESTONE AF3100, PRESTONE AF3055 and PEAK FCA1GAL, plus the other parts above.
Buying Cooling System Parts for a 2021 Freightliner FL
On this vehicle, the cooling system system keeps operating temperature in the narrow band the engine was designed for, from radiator and water pump to thermostat and hoses.
- You do not need to pick an engine: every cooling system part on this page fits all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged).
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, replace the thermostat and refill with fresh coolant whenever you change a water pump or radiator; original hoses on an older vehicle are on borrowed time.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Coolant / Antifreeze .
Frequently Asked Questions
How many cooling system parts fit the 2021 Freightliner FL?
Our catalog currently lists 9 cooling system parts for the 2021 Freightliner FL across 1 subcategory and 2 brands, covering all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged). Each part is matched to the engine(s) it fits.
Do cooling system parts differ between 2021 Freightliner FL engines?
No. On this page every cooling system part fits all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged). You do not need to pick an engine to choose the right row — use the notes for position and trim.
What are the signs of cooling system problems on a 2021 Freightliner FL?
Common symptoms include a rising temperature gauge in traffic, sweet-smelling steam, crusty deposits around hose clamps, or a heater that blows cold. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, replace the thermostat and refill with fresh coolant whenever you change a water pump or radiator; original hoses on an older vehicle are on borrowed time.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Freightliner FL was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Freightliner FL?
Every part on this page already fits all 3 engine options (3.0L L4 DIESEL Turbocharged, 3.9L L4 DIESEL Turbocharged and 6.4L L6 DIESEL Turbocharged). Then replace coolant with the exact specification the manufacturer calls for — mixing chemistries can gel and block small passages. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Freightliner FL
Cooling System Parts for Other Freightliner FL Years
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