1981 Checker Marathon Cooling System Parts

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. Read more

17 Coolant / Antifreeze parts for the 1981 Checker Marathon come from 4 brands — PEAK, PRESTONE, VALVOLINE and 1 other brand. The "Popular" part is FVP MV5050GAL. Every part fits all 4 engine options (3.8L 229cid V6, 4.4L 267cid V8, 5.0L 305cid V8 and 5.7L 350cid V8 DIESEL).

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 4 options from FVP, PRESTONE, PEAK and 1 other brand — the catalog's value-priced group. FVP MV5050GAL is listed in this group.

In the Heavy Duty grade, VALVOLINE supplies 1 part: rated for severe service. A representative part number is VALVOLINE ZXG051.

In the Premium grade, PRESTONE and PEAK supply 4 parts: a step above OE specification in materials, tolerances or warranty terms. A representative part number is PRESTONE AF2100.

In the Standard Replacement grade, PEAK, FVP, PRESTONE and 1 other brand supply 7 parts: built to original-equipment specification. A representative part number is FVP GREEN5050GAL.

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. Read more

12 Radiator Fan Clutch parts for the 1981 Checker Marathon come from 4 brands — FOUR SEASONS, HAYDEN, ACDELCO and 1 other brand. The "Popular" part is ACDELCO 1580244.

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. Read more

CONTINENTAL supplies the 3 Radiator Hose parts for the 1981 Checker Marathon.

Economy: 1 part, from CONTINENTAL. A representative part number is CONTINENTAL 52020.

The Standard Replacement section: 1 option from CONTINENTAL. CONTINENTAL 60365 is listed in this group.

1 ungrouped part is not assigned to a grade, with the same engine-level match.

Part numbers include CONTINENTAL 52020 and CONTINENTAL 60365, among others listed above.

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. Read more

34 Thermostat parts are listed for the 1981 Checker Marathon, from MOTORAD, CALORSTAT and GATES. MOTORAD 300180 carries the "Popular" badge. They are grouped as Economy, Heavy Duty, Performance, Premium and Standard Replacement, with Standard Replacement the largest group at 16 parts from CALORSTAT, MOTORAD and GATES.

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. Read more

13 Thermostat / Thermostat Housing / Water Outlet Seal parts for the 1981 Checker Marathon come from 6 brands — MAHLE / CLEVITE, FEL-PRO, MOTORAD and 3 other brands. The "Popular" part is FEL-PRO 35062. 1 part fits every engine; the other 12 are engine-specific.

This table covers the housings and outlets the thermostat sits in. Read more

11 Thermostat Housing / Water Outlet parts are listed for the 1981 Checker Marathon, from GPD, FOUR SEASONS, MOTORAD and 1 other brand.

Economy: 5 parts, from GPD and DORMAN. A representative part number is DORMAN 9022030.

The Standard Replacement section: 6 options from FOUR SEASONS and MOTORAD. FOUR SEASONS 84911 is listed in this group.

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. Read more

13 Water Pump parts are listed for the 1981 Checker Marathon, from GMB, US MOTOR WORKS, DAYCO and 5 other brands. US MOTOR WORKS US1121 carries the "Popular" badge. 8 parts fit every engine; the other 5 are engine-specific.

Economy: 4 parts, from US MOTOR WORKS, FVP, SKP and 1 other brand. A representative part number is US MOTOR WORKS US1121.

In the High Volume / Pressure grade, GMB and US MOTOR WORKS supply 4 parts: grouped under the catalog's "High Volume / Pressure" designation — the notes column spells out what sets them apart. A representative part number is GMB 1301250P.

The Standard Replacement section: 5 options from DAYCO, ACDELCO, GATES and 1 other brand. ACDELCO 252595 is listed in this group.

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. Read more

14 Water Pump Gasket parts for the 1981 Checker Marathon come from 4 brands — MAHLE / CLEVITE, VICTOR REINZ, FEL-PRO and 1 other brand. The "Popular" part is FEL-PRO 5152.

This table covers the Water Pump Stud kits. Read more

ARP supplies the 3 Water Pump Stud Kit parts for the 1981 Checker Marathon.

This group includes ARP 1343204, ARP 1343203 and ARP 4343203.