2021 Honda Civic 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

16 Coolant / Antifreeze parts are listed for the 2021 Honda Civic, from PRESTONE, PEAK, VALVOLINE and 4 other brands. FVP MV5050GAL carries the "Popular" badge. All of them fit every engine offered in the 2021 Civic.

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 Premium section lists 5 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 BECK/ARNLEY, VALVOLINE, AISIN and 2 other brands — built to original-equipment specification. VALVOLINE 861398 is listed in this group.

This table covers the seals at the Coolant Hose / Pipe. 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

5 Coolant Hose / Pipe Seal parts for the 2021 Honda Civic come from 4 brands — AJUSA, FEL-PRO, MAHLE / CLEVITE and 1 other brand. 1 part fits every engine; the other 4 are engine-specific.

Listed part numbers: AJUSA 16022400, AJUSA 16022450 and FEL-PRO 36022, plus the other parts above.

This table covers the overflow / expansion tanks that hold extra coolant. Read more

7 Coolant Reservoir parts for the 2021 Honda Civic come from 5 brands — TECHPRO, DORMAN, GPD and 2 other brands. The "Popular" part is DORMAN 603882. 3 parts fit every engine; the other 4 are engine-specific.

This group includes DORMAN 603882, TECHPRO HO3014137 and GPD 2411368 and the remaining parts above.

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. Read more

3 Coolant Reservoir Cap parts for the 2021 Honda Civic come from MOTORAD.

In the Locking Replacement grade, MOTORAD supplies 1 part: grouped under the catalog's "Locking Replacement" designation — the notes column spells out what sets them apart. A representative part number is MOTORAD ST16R.

Standard Replacement: 1 part, from MOTORAD. A representative part number is MOTORAD T16R.

1 further part sits outside the graded sections, with the same engine-level match.

Listed part numbers: MOTORAD ST16R and MOTORAD T16R, plus the other parts above.

This table covers the Cooling Fan control modules. Read more

This group shows a single part: STANDARD MOTOR PRODUCTS RY1931.

This table covers the adapters used to pressure-test this cooling system. Read more

MOTORAD supplies both parts for the 2021 Honda Civic. All of them fit every engine offered in the 2021 Civic.

Listed part numbers: MOTORAD 3121 and MOTORAD 3122.

This table covers the intercoolers that cool turbo or supercharger charge air. Read more

6 Intercooler parts are listed for the 2021 Honda Civic, from NISSENS, TYC, ACKOJA and 3 other brands. NISSENS 961527 carries the "Popular" badge.

Part numbers include NISSENS 961527, TYC 18061 and ACKOJA A26600005, among others listed above.

This table covers the Intercooler Air Hose pipes. Read more

6 Intercooler Air Hose / Pipe parts are listed for the 2021 Honda Civic, from GATES, DORMAN and ACKOJA. GATES 26564 carries the "Popular" badge.

This group includes GATES 26564, GATES 26568 and ACKOJA A269676 and the remaining parts above.

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. Read more

21 Radiator parts are listed for the 2021 Honda Civic, from TECHPRO, TYC, AGILITY and 10 other brands. CSF 3781 carries the "Popular" badge. 1 part fits every engine; the other 20 are engine-specific.

Economy: 4 parts, from TECHPRO, GPD and ULTRA-POWER. A representative part number is GPD 13582C.

The Standard Replacement section: 17 options from TYC, AGILITY, DENSO and 7 other brands. CSF 3781 is listed in this group.

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. Read more

One part is listed for the 2021 Honda Civic — CALORSTAT RC0007.

This table covers the fan assemblies (and clutches, where listed) that pull air through the radiator. Read more

11 Radiator Fan Assembly parts for the 2021 Honda Civic come from 8 brands — GPD, TYC, UAC and 5 other brands. The "Popular" part is DORMAN 621967. 1 part fits every engine; the other 10 are engine-specific.

The Economy section: 5 options from GPD, DORMAN, TECHPRO and 1 other brand. DORMAN 621967 is listed in this group.

Standard Replacement: 6 parts, from TYC, UAC, AGILITY and 1 other brand. A representative part number is TYC 624610.

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

14 Radiator Hose parts for the 2021 Honda Civic come from 3 brands — GATES, CONTINENTAL and DAYCO. The "Popular" part is CONTINENTAL 66497.

This table covers the Radiator insulators. Read more

This group shows a single part: TECHPRO HO3013100.

This table covers the Radiator Mount bushings. Typical signs include a clunk over bumps, or a torn or walked-out bushing you can see. Press the new bushing square. A cocked bushing will tear in a few thousand miles. Read more

2 Radiator Mount Bushing parts for the 2021 Honda Civic come from DORMAN. Every part fits all 3 engine options (1.5L L4 Turbocharged, 2.0L L4 and 2.0L L4 Turbocharged).

This group includes DORMAN 927240 and DORMAN 927241.

This table covers the senders that report coolant temperature to the gauge or ECU. Typical signs include a gauge that sits on empty or overheat, or a lamp that does not match what the engine is doing. Rule out the cluster and the wiring before replacing the sender. Read more

14 Temperature Sender / Sensor parts are listed for the 2021 Honda Civic, from STANDARD MOTOR PRODUCTS, HOLSTEIN, BECK/ARNLEY and 7 other brands. STANDARD MOTOR PRODUCTS TX215T carries the "Popular" badge. 10 parts fit every engine; the other 4 are engine-specific.

Economy: 6 parts, from HOLSTEIN, STANDARD MOTOR PRODUCTS, CALORSTAT and 2 other brands. A representative part number is STANDARD MOTOR PRODUCTS TX215T.

The Standard Replacement section: 8 options from BECK/ARNLEY, NTK, STANDARD MOTOR PRODUCTS and 3 other brands. STANDARD MOTOR PRODUCTS TX215 is listed in this group.

This table covers the Temperature Sender / Sensor O-rings. Typical signs include a seep at a fitting or a housing that weeps after a service. Lube the new O-ring with the fluid it will see, and do not roll it into the groove. Read more

One part is listed for the 2021 Honda Civic — FEL-PRO 72926.

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

18 Thermostat parts for the 2021 Honda Civic come from 8 brands — MOTORAD, BECK/ARNLEY, CALORSTAT and 5 other brands. The "Popular" part is DORMAN 902788.

The Economy section: 2 options from DORMAN and SKP. DORMAN 902788 is listed in this group.

Standard Replacement: 6 parts, from GATES, AISIN, BECK/ARNLEY and 3 other brands. A representative part number is GATES 34715.

10 further parts sit outside the graded sections, with the same engine-level match.

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 are listed for the 2021 Honda Civic, from FEL-PRO, MAHLE / CLEVITE, ELRING and 3 other brands. FEL-PRO 35741 carries the "Popular" badge.

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

6 Thermostat Housing / Water Outlet parts for the 2021 Honda Civic come from 3 brands — MOTORAD, FOUR SEASONS and GATES.

Listed part numbers: FOUR SEASONS 86279, GATES CO35003 and MOTORAD CH1023, plus the other parts above.

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

16 Water Pump parts for the 2021 Honda Civic come from 9 brands — US MOTOR WORKS, BECK/ARNLEY, FVP and 6 other brands. The "Popular" part is US MOTOR WORKS US8145.

The Economy section: 8 options from US MOTOR WORKS, BECK/ARNLEY, FVP and 2 other brands. US MOTOR WORKS US8145 is listed in this group.

Standard Replacement: 8 parts, from AISIN, DAYCO, GATES and 1 other brand. A representative part number is AISIN WPH076.

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

6 Water Pump Gasket parts are listed for the 2021 Honda Civic, from ELRING, MAHLE / CLEVITE, APEX and 1 other brand.

This group includes APEX AWP3318, ELRING 845830 and ELRING 108460 and the remaining parts above.

This table covers the Water Pump Seal O-rings. Typical signs include a seep at a fitting or a housing that weeps after a service. Lube the new O-ring with the fluid it will see, and do not roll it into the groove. Read more

This group shows a single part: FEL-PRO 36146.