The 2021 Freightliner 108SD has 30 cooling system parts with verified fitment on this page — 7 part types and 11 brands, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Each part includes a manufacturer part number and application notes.
On the 2021 Freightliner 108SD, 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. 22 parts of the 30 listed are Coolant / Antifreeze (11 parts), Thermostat (6 parts) and Intercooler (5 parts). The other 4 part types cover the remaining 8 parts.
The 2021 Freightliner 108SD was sold with 3 engines. 18 parts fit every engine; the other 12 are engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 Freightliner 108SD cooling system parts are PRESTONE (7 parts), GATES (4 parts) and SPECTRA PREMIUM (3 parts), plus 8 more brands. Quality grades include Heavy Duty, Standard Replacement and Universal Hose.
4 parts on this 2021 Freightliner 108SD page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including PRESTONE AF3100 (Coolant / Antifreeze) and SPECTRA PREMIUM 44011746 (Intercooler). 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 108SD engines | AF3055 | 🇺🇸 US 🇨🇦 CA | Prime YellowAll Vehicles | View on Amazon |
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Popular Fits: all 2021 108SD engines | AF3100 | 🇺🇸 US 🇨🇦 CA | Prime Yellow - All VehiclesExtended Life | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PEAK Fits: all 2021 108SD engines | FCA1GAL | 🇺🇸 US 🇨🇦 CA | Fleet Charge1 Gallon | View on Amazon |
| PEAK Fits: all 2021 108SD engines | FXA1GAL | 🇺🇸 US 🇨🇦 CA | Final Charge Global1 Gallon | View on Amazon |
| PRESTONE Fits: all 2021 108SD engines | AFC10000 | 🇺🇸 US 🇨🇦 CA | Command ESi PrechargedPurple | View on Amazon |
| PRESTONE Fits: all 2021 108SD engines | AFC13000 | 🇺🇸 US 🇨🇦 CA | Command COR-Guard Nitrite Free-Noat Extended Life CoolantRed | View on Amazon |
| PRESTONE Fits: all 2021 108SD engines | AFC12100 | 🇺🇸 US 🇨🇦 CA | Command Nitrite Free Extended Life CoolantYellow Nitrite Free OAT | View on Amazon |
| VALVOLINE Fits: all 2021 108SD engines | 846439 | 🇺🇸 US 🇨🇦 CA | HD Nitrite Free Extended Life Yellow1 Gallon | View on Amazon |
Premium
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Popular Fits: all 2021 108SD engines | AF2100 | 🇺🇸 US 🇨🇦 CA | All Vehicles10yr/300k mi | View on Amazon |
| PRESTONE Fits: all 2021 108SD engines | AFMAX | 🇺🇸 US 🇨🇦 CA | Max Universal1 Gallon | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE Popular Fits: all 2021 108SD engines | 861399 | 🇺🇸 US 🇨🇦 CA | G40 Pink1 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.
11 Coolant / Antifreeze parts for the 2021 Freightliner 108SD come from 3 brands — PRESTONE, PEAK and VALVOLINE. The "Popular" part is PRESTONE AF3100. Every part fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L 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, PEAK and VALVOLINE supply 6 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.
In the Standard Replacement grade, VALVOLINE supplies 1 part: built to original-equipment specification. A representative part number is VALVOLINE 861399.
Coolant Filter
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DONALDSON Fits: 8.9L L6 DIESEL Turbocharged | P554685 | 🇺🇸 US 🇨🇦 CA | Outer Diameter: 93 mm (3.66")Length: 136 mm (5.35") | View on Amazon |
This table covers the Coolant filters. Typical signs include restricted flow — long cranking, weak airflow, or dirty fluid after a short interval. Seat the new filter so it cannot bypass, and use the grade the notes call for.
This group shows a single part: DONALDSON P554685.
Intercooler
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SPECTRA PREMIUM Popular Fits: all 2021 108SD engines | 44011746 | 🇺🇸 US 🇨🇦 CA | with 42.625 IN X 21.625 IN X 1.9375 IN Corewith 3In Inlet | View on Amazon |
| GPD Fits: all 2021 108SD engines | 2711592 | 🇺🇸 US 🇨🇦 CA | with Compressor Port | View on Amazon |
| GPD Fits: all 2021 108SD engines | 2711593 | 🇺🇸 US 🇨🇦 CA | without Compressor Portwith Original Equipment (OE) # TXE10304844C | View on Amazon |
| SPECTRA PREMIUM Fits: all 2021 108SD engines | 44011749 | 🇺🇸 US 🇨🇦 CA | with 41.25 IN X 25.875 IN X 1.9375 IN Corewith 3In Inlet | View on Amazon |
| SPECTRA PREMIUM Fits: all 2021 108SD engines | 44011750 | 🇺🇸 US 🇨🇦 CA | with 1in compressor portwith 41.125 IN X 25.75 IN X 1.9375 IN Core | View on Amazon |
This table covers the intercoolers that cool turbo or supercharger charge air.
5 Intercooler parts for the 2021 Freightliner 108SD come from 2 brands — SPECTRA PREMIUM and GPD. The "Popular" part is SPECTRA PREMIUM 44011746. Every part fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged).
Part numbers include SPECTRA PREMIUM 44011746, GPD 2711592 and GPD 2711593, among others listed above.
Intercooler Air Hose / Pipe
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL Fits: 7.7L L6 DIESEL Turbocharged, 8.9L L6 DIESEL Turbocharged | 57504 | 🇺🇸 US 🇨🇦 CA | Convoluted Charge Air | View on Amazon |
| GATES Fits: all 2021 108SD engines | 26200 | 🇺🇸 US 🇨🇦 CA | Turbocharger Hose (Ring-Retained)Straight Hose | View on Amazon |
This table covers the Intercooler Air Hose pipes.
2 Intercooler Air Hose / Pipe parts for the 2021 Freightliner 108SD come from 2 brands — CONTINENTAL and GATES. 1 part fits every engine; the other 1 is engine-specific.
Part numbers include CONTINENTAL 57504 and GATES 26200.
Radiator
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD Fits: all 2021 108SD engines | 9282656 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the radiators that dump engine heat to airflow through the core. Typical signs include overheating in traffic, a wet core, or coolant that disappears with no puddle. Replace the cap if it cannot hold the rated pressure, and bleed the system after the swap.
This group shows a single part: GPD 9282656.
Radiator Hose
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 8.9L L6 DIESEL Turbocharged | 52169 | 🇺🇸 US 🇨🇦 CA | Molded | View on Amazon |
Universal Hose (Straight, Bulk)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ACDELCO Fits: 8.9L L6 DIESEL Turbocharged | 31062 | 🇺🇸 US 🇨🇦 CA | Gold / ProfessionalStraight | View on Amazon |
| CONTINENTAL Fits: 8.9L L6 DIESEL Turbocharged | 57040 | 🇺🇸 US 🇨🇦 CA | Heavy Duty Straight | View on Amazon |
| GATES Fits: 8.9L L6 DIESEL Turbocharged | 24236 | 🇺🇸 US 🇨🇦 CA | Straight (Heavy-Duty 2-Ply)2.25" Inner Diameter | View on Amazon |
This table covers the upper, lower and connecting hoses between radiator, engine and reservoir. Typical signs include swelling, cracks, a soft spot, or a leak at a clamp. Replace adjacent aged hoses while the system is drained — they share the same heat cycle.
4 Radiator Hose parts are listed for the 2021 Freightliner 108SD, from GATES, ACDELCO and CONTINENTAL.
The Standard Replacement section: 1 option from GATES. GATES 52169 is listed in this group.
The Universal Hose (Straight, Bulk) section lists 3 options from ACDELCO, CONTINENTAL and GATES — grouped under the catalog's "Universal Hose (Straight, Bulk)" designation — the notes column spells out what sets them apart. ACDELCO 31062 is listed in this group.
This group includes GATES 52169, ACDELCO 31062 and CONTINENTAL 57040 and the remaining parts above.
Thermostat
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 8.9L L6 DIESEL Turbocharged | 34308 | 🇺🇸 US 🇨🇦 CA | Heavy-Duty | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CALORSTAT Fits: 8.9L L6 DIESEL Turbocharged | TH713082J | 🇺🇸 US 🇨🇦 CA | PerformanceIncludes 1 Rubber Gasket | View on Amazon |
| MOTORAD Fits: 8.9L L6 DIESEL Turbocharged | 407160 | 🇺🇸 US 🇨🇦 CA | Includes Seal | View on Amazon |
| MOTORAD Fits: 8.9L L6 DIESEL Turbocharged | 407180 | 🇺🇸 US 🇨🇦 CA | Includes Seal | View on Amazon |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CALORSTAT Fits: 6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged | TH713082J | 🇺🇸 US 🇨🇦 CA | PerformanceIncludes 1 Rubber Gasket | View on Amazon |
| MOTORAD Fits: 6.7L L6 DIESEL Turbocharged | 923192 | 🇺🇸 US | Includes Seal | View on Amazon |
This table covers the thermostats that open the coolant circuit at the specified temperature. Typical signs include slow warm-up, a gauge that climbs in traffic, or heat that never quite arrives. Replace the housing gasket with the thermostat and bleed the system so a trapped air pocket does not cook the new part.
6 Thermostat parts are listed for the 2021 Freightliner 108SD, from MOTORAD, CALORSTAT and GATES.
The Heavy Duty section: 1 option from GATES. GATES 34308 is listed in this group.
The Standard Replacement section: 3 options from MOTORAD and CALORSTAT. CALORSTAT TH713082J is listed in this group.
2 ungrouped parts are not assigned to a grade, with the same engine-level match.
This group includes GATES 34308, CALORSTAT TH713082J and MOTORAD 407160 and the remaining parts above.
Buying Cooling System Parts for a 2021 Freightliner 108SD
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.
- Match the engine first. Some cooling system parts fit every engine; others are engine-specific. Each row shows which engine(s) it fits.
- 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 and Thermostat .
Frequently Asked Questions
How many cooling system parts fit the 2021 Freightliner 108SD?
Our catalog currently lists 30 cooling system parts for the 2021 Freightliner 108SD across 7 subcategories and 11 brands, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Each part is matched to the engine(s) it fits.
Do cooling system parts differ between 2021 Freightliner 108SD engines?
Some do. 18 parts fit every engine; the other 12 are engine-specific. Each row (and the filter at the top) shows which. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of cooling system problems on a 2021 Freightliner 108SD?
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 108SD 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 108SD?
First match the engine — each row shows which engine(s) the part fits. 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 108SD
Cooling System Parts for Other Freightliner 108SD Years
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