29 Cooling system parts are listed for the 2021 International Lonestar, in 8 part types, covering the 14.9L L6 DIESEL Turbocharged engine. Each one has a brand, a manufacturer part number and notes that say where it fits.
The cooling system system on the 2021 International Lonestar keeps operating temperature in the narrow band the engine was designed for, from radiator and water pump to thermostat and hoses. The largest groups are Coolant / Antifreeze (9 parts), Thermostat (7 parts) and Radiator Hose (4 parts). The other 5 part types cover the remaining 9 parts.
The 2021 International Lonestar came with a single engine, the 14.9L L6 DIESEL Turbocharged, and every part is verified against it.
10 brands supply cooling system parts for the 2021 International Lonestar, led by GATES (6 parts), MOTORAD (5 parts) and VALVOLINE (4 parts), plus 7 more brands. Quality grades include Standard Replacement, Heavy Duty and Economy.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 2021 International Lonestar. 4 parts have it, including VALVOLINE ZXG051 (Coolant / Antifreeze) and GATES 34148 (Thermostat). Each part number opens a page with every vehicle that part fits.
Coolant / Antifreeze
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE | 719009 | 🇺🇸 US 🇨🇦 CA | Multi-Vehicle Yellow1 Gallon | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE Popular | ZXG051 | 🇺🇸 US 🇨🇦 CA | G05 Yellow1 Gallon | View on Amazon |
| PEAK | FCA1GAL | 🇺🇸 US 🇨🇦 CA | Fleet Charge1 Gallon | View on Amazon |
| PEAK | FXA1GAL | 🇺🇸 US 🇨🇦 CA | Final Charge Global1 Gallon | View on Amazon |
| PRESTONE | AFC10000 | 🇺🇸 US 🇨🇦 CA | Command ESi PrechargedPurple | View on Amazon |
| PRESTONE | AFC13000 | 🇺🇸 US 🇨🇦 CA | Command COR-Guard Nitrite Free-Noat Extended Life CoolantRed | View on Amazon |
| PRESTONE | AFC12100 | 🇺🇸 US 🇨🇦 CA | Command Nitrite Free Extended Life CoolantYellow Nitrite Free OAT | View on Amazon |
| VALVOLINE | 846439 | 🇺🇸 US 🇨🇦 CA | HD Nitrite Free Extended Life Yellow1 Gallon | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE Popular | ZX001 | 🇺🇸 US 🇨🇦 CA | Original Green1 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 are listed for the 2021 International Lonestar, from VALVOLINE, PRESTONE and PEAK. VALVOLINE ZXG051 carries the "Popular" badge.
In the Economy grade, VALVOLINE supplies 1 part: the catalog's value-priced group. A representative part number is VALVOLINE 719009.
The Heavy Duty section lists 7 options from PRESTONE, VALVOLINE and PEAK — rated for severe service. VALVOLINE ZXG051 is listed in this group.
The Standard Replacement section lists 1 option from VALVOLINE — built to original-equipment specification. VALVOLINE ZX001 is listed in this group.
This group includes VALVOLINE ZXG051, VALVOLINE 719009 and PEAK FCA1GAL and the remaining parts above.
Coolant Reservoir
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD | 2421012 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the overflow / expansion tanks that hold extra coolant.
This group shows a single part: GPD 2421012.
Coolant Reservoir Cap
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES | 31405 | 🇺🇸 US 🇨🇦 CA | OE Type | View on Amazon |
| MOTORAD | T39 | 🇺🇸 US 🇨🇦 CA | Standard | View on Amazon |
This table covers the caps on the overflow / expansion tank. Typical signs include a leak at the neck, a cap that will not hold pressure, or a missing tether. Match the pressure rating or thread in the notes — radiator, reservoir and fuel caps are not interchangeable.
2 Coolant Reservoir Cap parts for the 2021 International Lonestar come from 2 brands — GATES and MOTORAD.
This group includes GATES 31405 and MOTORAD T39.
Hose Clamp
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DORMAN | 9044000 | 🇺🇸 US 🇨🇦 CA | 1.75" DiameterCoolant | View on Amazon |
This table covers the Hose clamps.
One part is listed for the 2021 International Lonestar — DORMAN 9044000.
Intercooler Air Hose / Pipe
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL | 57513 | 🇺🇸 US 🇨🇦 CA | Convoluted Charge Air | View on Amazon |
| GATES | 26204 | 🇺🇸 US 🇨🇦 CA | Turbocharger Hose (Ring-Retained)4" x 8" (110 psi) | View on Amazon |
| GATES | 26203 | 🇺🇸 US 🇨🇦 CA | Turbocharger Hose (Ring-Retained)4" x 6" (110 psi) | View on Amazon |
This table covers the Intercooler Air Hose pipes.
3 Intercooler Air Hose / Pipe parts are listed for the 2021 International Lonestar, from GATES and CONTINENTAL.
Part numbers include CONTINENTAL 57513, GATES 26204 and GATES 26203.
Radiator Hose
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CONTINENTAL | 66552 | 🇺🇸 US 🇨🇦 CA | Molded | View on Amazon |
| DAYCO | 71813 | 🇺🇸 US 🇨🇦 CA | Molded | View on Amazon |
| GATES | 21891 | 🇺🇸 US 🇨🇦 CA | Molded | View on Amazon |
Universal Hose (Straight, Bulk)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES | 24440 | 🇺🇸 US 🇨🇦 CA | Straight (Heavy-Duty 4-Ply)2.5" (75 PSI) | 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 for the 2021 International Lonestar come from 3 brands — GATES, CONTINENTAL and DAYCO.
Standard Replacement: 3 parts, from CONTINENTAL, DAYCO and GATES. A representative part number is CONTINENTAL 66552.
In the Universal Hose (Straight, Bulk) grade, GATES supplies 1 part: grouped under the catalog's "Universal Hose (Straight, Bulk)" designation — the notes column spells out what sets them apart. A representative part number is GATES 24440.
This group includes CONTINENTAL 66552, DAYCO 71813 and GATES 21891 and the remaining parts above.
Thermostat
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Popular | 34148 | 🇺🇸 US 🇨🇦 CA | Heavy-Duty | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Popular | 406190 | 🇺🇸 US 🇨🇦 CA | Includes Seal | View on Amazon |
| CALORSTAT | THS1910582 | 🇺🇸 US 🇨🇦 CA | PerformanceDoes Not Include Seal | View on Amazon |
| CALORSTAT | THS1910588 | 🇺🇸 US 🇨🇦 CA | Does not include seal | View on Amazon |
| MOTORAD | 406160 | 🇺🇸 US 🇨🇦 CA | Includes Seal | View on Amazon |
| MOTORAD | 407825 | 🇺🇸 US 🇨🇦 CA | 225 Degrees Ffor Engine Oil Cooler System | View on Amazon |
| MOTORAD | 406180 | 🇺🇸 US 🇨🇦 CA | 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.
7 Thermostat parts for the 2021 International Lonestar come from 3 brands — MOTORAD, CALORSTAT and GATES. The "Popular" part is GATES 34148.
Heavy Duty: 1 part, from GATES. A representative part number is GATES 34148.
Standard Replacement: 6 parts, from MOTORAD and CALORSTAT. A representative part number is MOTORAD 406190.
Listed part numbers: GATES 34148, MOTORAD 406190 and CALORSTAT THS1910582, plus the other parts above.
Thermostat / Thermostat Housing / Water Outlet Seal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DORMAN | 6745003G | 🇺🇸 US 🇨🇦 CA | Housing to Flange | View on Amazon |
| DORMAN | 6745008G | 🇺🇸 US 🇨🇦 CA | Housing to Cylinder Head | View on Amazon |
This table covers the seals at the thermostat housing and water outlet. Typical signs include a wet housing, a drip after sitting, or fluid flung off a rotating shaft. Fix the surface the seal rides on. A new seal on a grooved shaft will leak again.
DORMAN supplies both parts for the 2021 International Lonestar.
Listed part numbers: DORMAN 6745003G and DORMAN 6745008G.
Buying Cooling System Parts for a 2021 International Lonestar
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.
- Confirm you have the 14.9L L6 DIESEL Turbocharged engine — every part on this page is matched to it.
- 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 International Lonestar?
Our catalog currently lists 29 cooling system parts for the 2021 International Lonestar across 8 subcategories and 10 brands, covering the 14.9L L6 DIESEL Turbocharged engine. Each part is matched to the engine(s) it fits.
What are the signs of cooling system problems on a 2021 International Lonestar?
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 International Lonestar 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 International Lonestar?
Every part on this page is matched to the 14.9L L6 DIESEL Turbocharged engine. 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 International Lonestar
Cooling System Parts for Other International Lonestar Years
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