The 1966 Checker Marathon has 123 cooling system parts with verified fitment on this page — 11 part types and 20 brands, covering all 4 engine options (3.8L 230cid L6, 4.6L 283cid V8, 5.2L 318cid V8 and 5.3L 327cid V8). Each part includes a manufacturer part number and application notes.
On the 1966 Checker Marathon, 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. Most of the listed parts are Thermostat (22 parts), Radiator Fan Clutch (19 parts) and Radiator Hose (18 parts). The other 8 part types cover the remaining 64 parts.
The 1966 Checker Marathon was sold with 4 engines. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
20 brands supply cooling system parts for the 1966 Checker Marathon, led by MOTORAD (22 parts), GATES (12 parts) and DAYCO (10 parts), plus 17 more brands. Quality grades include Standard Replacement, Economy and Premium.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 1966 Checker Marathon. 26 parts have it, including FVP MV5050GAL (Coolant / Antifreeze) and MOTORAD T13 (Radiator Cap). Each part number opens a page with every vehicle that part fits.
Coolant / Antifreeze
Compatible With All Colors
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | AF3055 | 🇺🇸 US 🇨🇦 CA | Prime YellowAll Vehicles | View on Amazon |
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FVP Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | MV5050GAL | 🇺🇸 US 🇨🇦 CA | Extended LifeAll Makes / All Models | View on Amazon |
| PRESTONE Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | AF3100 | 🇺🇸 US 🇨🇦 CA | Prime Yellow - All VehiclesExtended Life | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | BQA1GAL | 🇺🇸 US 🇨🇦 CA | Blue Mountain Long LifeAll Vehicle | View on Amazon |
| VALVOLINE Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 719009 | 🇺🇸 US 🇨🇦 CA | Multi-Vehicle Yellow1 Gallon | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VALVOLINE Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | ZXG051 | 🇺🇸 US 🇨🇦 CA | G05 Yellow1 Gallon | View on Amazon |
Premium
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PRESTONE Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | AF2100 | 🇺🇸 US 🇨🇦 CA | All Vehicles10yr/300k mi | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | PKP1GAL | 🇺🇸 US 🇨🇦 CA | All Vehicles Antifreeze1 Gallon | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | PXA1GAL | 🇺🇸 US 🇨🇦 CA | Global Lifetime1 Gallon | View on Amazon |
| PRESTONE Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | AFMAX | 🇺🇸 US 🇨🇦 CA | Max Universal1 Gallon | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FVP Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | GREEN5050GAL | 🇺🇸 US 🇨🇦 CA | Low Silicate Blend1 Gallon | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | BMA1GAL | 🇺🇸 US 🇨🇦 CA | Blue Mountain Conventional Green1 Gallon | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | RUA1GAL | 🇺🇸 US 🇨🇦 CA | Conventional Green1 Gallon | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | FFA1GAL | 🇺🇸 US 🇨🇦 CA | Full Force Conventional Green1 Gallon | View on Amazon |
| PEAK Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | SEP1GAL | 🇺🇸 US 🇨🇦 CA | Sierra Conventional Green Concentrate Low Toxic Option1 Gallon | View on Amazon |
| PRESTONE Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | AF3300 | 🇺🇸 US 🇨🇦 CA | Prime Conventional Green 1 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.
16 Coolant / Antifreeze parts are listed for the 1966 Checker Marathon, from PEAK, PRESTONE, FVP and 1 other brand. FVP MV5050GAL carries the "Popular" badge.
The Compatible With All Colors section lists 1 option from PRESTONE — grouped under the catalog's "Compatible With All Colors" designation — the notes column spells out what sets them apart. PRESTONE AF3055 is listed in this group.
In the Economy grade, FVP, PRESTONE, PEAK and 1 other brand supply 4 parts: the catalog's value-priced group. A representative part number is FVP MV5050GAL.
The Heavy Duty section lists 1 option from VALVOLINE — rated for severe service. VALVOLINE ZXG051 is listed in this group.
The Premium section lists 4 options from PRESTONE and PEAK — a step above OE specification in materials, tolerances or warranty terms. PRESTONE AF2100 is listed in this group.
The Standard Replacement section lists 6 options from PEAK, FVP and PRESTONE — built to original-equipment specification. FVP GREEN5050GAL is listed in this group.
Cooling System Tester Adapter
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 31413 | 🇺🇸 US | Cooling System PressureRadiator Cap | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 3003 | 🇺🇸 US | StandardIncluded In Tester Kit | View on Amazon |
This table covers the adapters used to pressure-test this cooling system.
2 Cooling System Tester Adapter parts are listed for the 1966 Checker Marathon, from GATES and MOTORAD.
This group includes GATES 31413 and MOTORAD 3003.
Radiator Cap
Locking Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 31511 | 🇺🇸 US | Safety Release Radiator Cap | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | ST13 | 🇺🇸 US | Safety Lever | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | T13 | 🇺🇸 US | Standard | View on Amazon |
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 31527 | 🇺🇸 US | OE Type | View on Amazon |
| SKP Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | SK10229 | 🇺🇸 US | Pressure Rating 13 psi | View on Amazon |
This table covers the caps that hold system pressure at the radiator or reservoir neck. 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.
5 Radiator Cap parts are listed for the 1966 Checker Marathon, from GATES, MOTORAD and SKP. MOTORAD T13 carries the "Popular" badge.
The Locking Replacement section lists 2 options from GATES and MOTORAD — grouped under the catalog's "Locking Replacement" designation — the notes column spells out what sets them apart. GATES 31511 is listed in this group.
The Standard Replacement section: 3 options from MOTORAD, GATES and SKP. MOTORAD T13 is listed in this group.
This group includes MOTORAD T13, GATES 31511 and MOTORAD ST13 and the remaining parts above.
Radiator Fan Clutch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ACDELCO Popular Fits: 3.8L 230cid L6 | 1580244 | 🇺🇸 US 🇨🇦 CA | GoldNon-Thermal | View on Amazon |
| FOUR SEASONS Popular Fits: 3.8L 230cid L6 | 36952 | 🇺🇸 US | Standard Duty Thermal | View on Amazon |
| FOUR SEASONS Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 36954 | 🇺🇸 US | Standard Duty Thermal3.33" Overall Height | View on Amazon |
| HAYDEN Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 2710 | 🇺🇸 US | ThermalStandard Duty | View on Amazon |
| ACDELCO Fits: 3.8L 230cid L6 | 1580245 | 🇺🇸 US 🇨🇦 CA | GoldStandard Duty Thermal | View on Amazon |
| ACDELCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1580277 | 🇺🇸 US 🇨🇦 CA | GoldStandard Duty Thermal | View on Amazon |
| FOUR SEASONS Fits: 3.8L 230cid L6 | 36949 | 🇺🇸 US | Non-Thermal | View on Amazon |
| FOUR SEASONS Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 36911 | 🇺🇸 US | Non-Thermal3.33" Overall Height | View on Amazon |
| FVP Fits: 5.3L 327cid V8 | 21016 | 🇺🇸 US | Non-Thermal | View on Amazon |
| GPD Fits: 3.8L 230cid L6 | 2911276 | 🇺🇸 US | Thermal | View on Amazon |
| GPD Fits: 3.8L 230cid L6 | 2911376 | 🇺🇸 US | Standard Duty | View on Amazon |
| GPD Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 2911277 | 🇺🇸 US | ThermalStandard Duty | View on Amazon |
| HAYDEN Fits: 3.8L 230cid L6 | 1705 | 🇺🇸 US | Non-Thermal | View on Amazon |
| HAYDEN Fits: 3.8L 230cid L6 | 2705 | 🇺🇸 US | ThermalStandard Duty | View on Amazon |
| HAYDEN Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1710 | 🇺🇸 US | Non-Thermal | View on Amazon |
| SKP Fits: 3.8L 230cid L6 | SK36952 | 🇺🇸 US | Standard Duty Thermal | View on Amazon |
| SKP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | SK36954 | 🇺🇸 US | Standard Duty Thermal | View on Amazon |
| SKP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | SK36911 | 🇺🇸 US | Non-Thermal | View on Amazon |
| US MOTOR WORKS Fits: 5.3L 327cid V8 | 21016 | 🇺🇸 US | Non-Thermal | View on Amazon |
This table covers the Radiator Fan clutches. Typical signs include slip at highway speed, chatter on takeoff, or a pedal that stays low. Resurface or replace the flywheel with the clutch — a heat-checked flywheel wastes the new disc.
19 Radiator Fan Clutch parts are listed for the 1966 Checker Marathon, from FOUR SEASONS, HAYDEN, ACDELCO and 4 other brands. ACDELCO 1580244 carries the "Popular" badge.
Radiator Hose
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular Fits: 3.8L 230cid L6 | 81141 | 🇺🇸 US | Flex Radiator Hose | View on Amazon |
| ACDELCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 31637 | 🇺🇸 US 🇨🇦 CA | Gold / ProfessionalFlexible | View on Amazon |
| CONTINENTAL Fits: 3.8L 230cid L6 | 52412 | 🇺🇸 US | FlexibleHose 1 Length: 12.19 In | View on Amazon |
| CONTINENTAL Fits: 3.8L 230cid L6 | 52818 | 🇺🇸 US | FlexibleHose 1 Length: 18.81 In | View on Amazon |
| DAYCO Fits: 3.8L 230cid L6 | 81341 | 🇺🇸 US | Flex Radiator Hose | View on Amazon |
| DAYCO Fits: 4.6L 283cid V8 | 81171 | 🇺🇸 US | Flex Radiator Hose | View on Amazon |
| DAYCO Fits: 4.6L 283cid V8 | 81331 | 🇺🇸 US | Flex Radiator Hose | View on Amazon |
| GATES Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 25478 | 🇺🇸 US | Flexible | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular Fits: 3.8L 230cid L6 | 70081 | 🇺🇸 US | Curved | View on Amazon |
| GATES Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 20475 | 🇺🇸 US | Molded | View on Amazon |
| GATES Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 20993 | 🇺🇸 US | Molded | View on Amazon |
| ACDELCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 22105M | 🇺🇸 US 🇨🇦 CA | Professional / GoldMolded | View on Amazon |
| ACDELCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 20026S | 🇺🇸 US 🇨🇦 CA | Professional / GoldMolded | View on Amazon |
| CONTINENTAL Fits: 3.8L 230cid L6 | 60859 | 🇺🇸 US | Molded | View on Amazon |
| CONTINENTAL Fits: 3.8L 230cid L6 | 60608 | 🇺🇸 US | Molded | View on Amazon |
| CONTINENTAL Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 60292 | 🇺🇸 US | Molded | View on Amazon |
| DAYCO Fits: 3.8L 230cid L6 | 70391 | 🇺🇸 US | Curved | View on Amazon |
| DAYCO Fits: 4.6L 283cid V8 | 70368 | 🇺🇸 US | Curved | 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.
18 Radiator Hose parts for the 1966 Checker Marathon come from 4 brands — DAYCO, CONTINENTAL, ACDELCO and 1 other brand. The "Popular" part is DAYCO 81141.
The Economy section: 8 options from DAYCO, CONTINENTAL, ACDELCO and 1 other brand. DAYCO 81141 is listed in this group.
Standard Replacement: 10 parts, from DAYCO, CONTINENTAL, GATES and 1 other brand. A representative part number is DAYCO 70081.
Thermostat
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33508 | 🇺🇸 US | Economy | View on Amazon |
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33509 | 🇺🇸 US | Economy | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 300160 | 🇺🇸 US | Economy | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 300195 | 🇺🇸 US | Economy | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 300180 | 🇺🇸 US | Economy | View on Amazon |
Heavy Duty
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 5200160 | 🇺🇸 US | Ultra Stat | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 5200180 | 🇺🇸 US | Ultra Stat | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 5200195 | 🇺🇸 US | Ultra Stat | View on Amazon |
Performance
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 2000160 | 🇺🇸 US | High Flow | View on Amazon |
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 2000180 | 🇺🇸 US | High Flow | View on Amazon |
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 2000195 | 🇺🇸 US | High Flow | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | MRD100 | 🇺🇸 US | Racing Thermostat | View on Amazon |
Premium
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 7200180 | 🇺🇸 US | Fail-Safe | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 7200195 | 🇺🇸 US | Fail-Safe | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 7200160 | 🇺🇸 US | Fail-Safe | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 200195 | 🇺🇸 US | Standard | View on Amazon |
| MOTORAD Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 200180 | 🇺🇸 US | Standard | View on Amazon |
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33009 | 🇺🇸 US | OE Type | View on Amazon |
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33006 | 🇺🇸 US | OE Type | View on Amazon |
| GATES Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33008 | 🇺🇸 US | OE Type | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 200205 | 🇺🇸 US | Standard | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 200160 | 🇺🇸 US | Standard | 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.
22 Thermostat parts for the 1966 Checker Marathon come from 2 brands — MOTORAD and GATES. The "Popular" part is MOTORAD 2000160.
The Economy section: 5 options from MOTORAD and GATES. GATES 33508 is listed in this group.
Heavy Duty: 3 parts, from MOTORAD. A representative part number is MOTORAD 5200160.
The Performance section lists 4 options from MOTORAD — engineered beyond original-equipment specification. MOTORAD 2000160 is listed in this group.
Premium: 3 parts, from MOTORAD. A representative part number is MOTORAD 7200180.
Standard Replacement: 7 parts, from MOTORAD and GATES. A representative part number is MOTORAD 200195.
Thermostat / Thermostat Housing / Water Outlet Seal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FEL-PRO Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 35062 | 🇺🇸 US | 1-13/16 (In) Inside DiameterComposite Material | View on Amazon |
| GATES Popular Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 33624 | 🇺🇸 US | Thermostat Gasket - 1 27/32" | View on Amazon |
| FEL-PRO Fits: 3.8L 230cid L6 | 13224 | 🇺🇸 US | Housing to Cylinder Head | View on Amazon |
| FEL-PRO Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 35562T | 🇺🇸 US | Permadryplus | View on Amazon |
| MAHLE / CLEVITE Fits: 3.8L 230cid L6 | C26544 | 🇺🇸 US | Paper | View on Amazon |
| MAHLE / CLEVITE Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | C24109 | 🇺🇸 US | PaperUniversal Type | View on Amazon |
| MAHLE / CLEVITE Fits: 4.6L 283cid V8, 5.3L 327cid V8 | C25930 | 🇺🇸 US | Paper | View on Amazon |
| MAHLE / CLEVITE Fits: 4.6L 283cid V8, 5.3L 327cid V8 | C32721 | 🇺🇸 US | Molded Rubber with Plastic CarrierWater Outlet Seal | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | MG38 | 🇺🇸 US | View on Amazon | |
| VICTOR REINZ Fits: 3.8L 230cid L6 | 711353700 | 🇺🇸 US | Housing to HeadThermostat Seal | View on Amazon |
| VICTOR REINZ Fits: 3.8L 230cid L6, 4.6L 283cid V8, 5.3L 327cid V8 | 711359200 | 🇺🇸 US | Rigid CarrierWater Outlet | 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.
11 Thermostat / Thermostat Housing / Water Outlet Seal parts are listed for the 1966 Checker Marathon, from MAHLE / CLEVITE, FEL-PRO, VICTOR REINZ and 2 other brands. FEL-PRO 35062 carries the "Popular" badge.
Thermostat Housing / Water Outlet
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DORMAN Fits: 3.8L 230cid L6 | 9022018 | 🇺🇸 US | Thermostat Housing | View on Amazon |
| GPD Fits: 3.8L 230cid L6 | 8241278 | 🇺🇸 US | Water Outlet | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FOUR SEASONS Fits: 3.8L 230cid L6 | 84852 | 🇺🇸 US | Water Outlet | View on Amazon |
| MOTORAD Fits: 3.8L 230cid L6 | CH4852 | 🇺🇸 US | Includes Gasket and Plug | View on Amazon |
This table covers the housings and outlets the thermostat sits in.
4 Thermostat Housing / Water Outlet parts for the 1966 Checker Marathon come from 4 brands — DORMAN, GPD, FOUR SEASONS and 1 other brand.
The Economy section: 2 options from DORMAN and GPD. DORMAN 9022018 is listed in this group.
Standard Replacement: 2 parts, from FOUR SEASONS and MOTORAD. A representative part number is FOUR SEASONS 84852.
Listed part numbers: DORMAN 9022018, GPD 8241278 and FOUR SEASONS 84852, plus the other parts above.
Water Pump
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FVP Fits: 3.8L 230cid L6 | US895 | 🇺🇸 US | View on Amazon | |
| FVP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | US898 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| US MOTOR WORKS Fits: 3.8L 230cid L6 | US895 | 🇺🇸 US | View on Amazon | |
| US MOTOR WORKS Fits: 4.6L 283cid V8, 5.3L 327cid V8 | US898 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
High Volume / Pressure
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GMB Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1301350P | 🇺🇸 US | High Performance | View on Amazon |
| US MOTOR WORKS Fits: 3.8L 230cid L6 | US895H | 🇺🇸 US | Base ModelHigh Performance | View on Amazon |
| US MOTOR WORKS Fits: 4.6L 283cid V8, 5.3L 327cid V8 | US898H | 🇺🇸 US 🇨🇦 CA | High Performance | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DAYCO Popular Fits: 3.8L 230cid L6 | DP846 | 🇺🇸 US | Standard Dutywith Belt Driven Pump | View on Amazon |
| GMB Popular Fits: 3.8L 230cid L6 | 1301010 | 🇺🇸 US | View on Amazon | |
| GMB Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1301350 | 🇺🇸 US | View on Amazon | |
| DAYCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | DP1313 | 🇺🇸 US | Standard Dutywith Belt Driven Pump | View on Amazon |
| DAYCO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | DP1331 | 🇺🇸 US | Heavy Duty | View on Amazon |
| GMB Fits: 3.8L 230cid L6 | 1301010AL | 🇺🇸 US | Aluminum Body | View on Amazon |
This table covers the pumps that circulate coolant through the block and radiator. Typical signs include coolant at the weep hole, pulley play, or a growl from the front of the engine. Replace the thermostat and refill with the specified coolant whenever the pump comes off.
13 Water Pump parts for the 1966 Checker Marathon come from 4 brands — US MOTOR WORKS, GMB, DAYCO and 1 other brand. The "Popular" part is GMB 1301350P.
The Economy section: 4 options from FVP and US MOTOR WORKS. FVP US895 is listed in this group.
The High Volume / Pressure section lists 3 options from US MOTOR WORKS and GMB — grouped under the catalog's "High Volume / Pressure" designation — the notes column spells out what sets them apart. GMB 1301350P is listed in this group.
Standard Replacement: 6 parts, from DAYCO and GMB. A representative part number is DAYCO DP846.
Water Pump Gasket
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FEL-PRO Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 5152 | 🇺🇸 US | To Block3 Bolt Gasket | View on Amazon |
| FEL-PRO Popular Fits: 4.6L 283cid V8, 5.3L 327cid V8 | ES73030 | 🇺🇸 US | Gasket Kit | View on Amazon |
| FEL-PRO Fits: 3.8L 230cid L6 | 13243 | 🇺🇸 US | To BlockOriginal Equipment (OE) Part Number 3788478, 10003210, 10007042 | View on Amazon |
| FEL-PRO Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 13032 | 🇺🇸 US | To BlockBacking Plate | View on Amazon |
| MAHLE / CLEVITE Fits: 3.8L 230cid L6 | K26545 | 🇺🇸 US | Paper | View on Amazon |
| MAHLE / CLEVITE Fits: 4.6L 283cid V8, 5.3L 327cid V8 | K25935 | 🇺🇸 US | Paper | View on Amazon |
| MAHLE / CLEVITE Fits: 4.6L 283cid V8, 5.3L 327cid V8 | K27091 | 🇺🇸 US | Paper | View on Amazon |
| VICTOR REINZ Fits: 3.8L 230cid L6 | 711398300 | 🇺🇸 US | View on Amazon | |
| VICTOR REINZ Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 711465400 | 🇺🇸 US | Paper | View on Amazon |
| VICTOR REINZ Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 711465700 | 🇺🇸 US | Paper | View on Amazon |
This table covers the gaskets between the water pump and the block or housing. Typical signs include seepage at the joint, a burnt-oil smell, or a leak that appears only after a long drive. Clean both flanges and torque in the sequence the notes or the manual call for.
10 Water Pump Gasket parts are listed for the 1966 Checker Marathon, from FEL-PRO, MAHLE / CLEVITE and VICTOR REINZ. FEL-PRO 5152 carries the "Popular" badge.
Water Pump Stud Kit
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ARP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1343204 | 🇺🇸 US 🇨🇦 CA | Hex Bolt Head | View on Amazon |
| ARP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 1343203 | 🇺🇸 US 🇨🇦 CA | Black Oxide12 Point Bolt Head | View on Amazon |
| ARP Fits: 4.6L 283cid V8, 5.3L 327cid V8 | 4343203 | 🇺🇸 US 🇨🇦 CA | Stainless Steel12 Point Bolt Head | View on Amazon |
This table covers the Water Pump Stud kits.
3 Water Pump Stud Kit parts for the 1966 Checker Marathon come from ARP.
Listed part numbers: ARP 1343204, ARP 1343203 and ARP 4343203.
Buying Cooling System Parts for a 1966 Checker Marathon
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. Every cooling system part here is 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: Thermostat and Radiator Fan Clutch .
Frequently Asked Questions
How many cooling system parts fit the 1966 Checker Marathon?
Our catalog currently lists 123 cooling system parts for the 1966 Checker Marathon across 11 subcategories and 20 brands, covering all 4 engine options (3.8L 230cid L6, 4.6L 283cid V8, 5.2L 318cid V8 and 5.3L 327cid V8). Each part is matched to the engine(s) it fits.
Do cooling system parts differ between 1966 Checker Marathon engines?
Yes. Every cooling system part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. 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 1966 Checker Marathon?
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 1966 Checker Marathon 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 1966 Checker Marathon?
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 1966 Checker Marathon
Cooling System Parts for Other Checker Marathon Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.