2021 Toyota Prius 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 2021 Toyota Prius come from 7 brands — PRESTONE, PEAK, AISIN and 4 other brands. The "Popular" part is FVP MV5050GAL.

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

In the Premium grade, PRESTONE and PEAK supply 5 parts: a step above OE specification in materials, tolerances or warranty terms. A representative part number is PRESTONE AF2100.

In the Standard Replacement grade, AISIN, VALVOLINE, BECK/ARNLEY and 2 other brands supply 8 parts: built to original-equipment specification. A representative part number is AISIN ACT002.

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

One part is listed for the 2021 Toyota Prius — TECHPRO TO3014143.

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 are listed for the 2021 Toyota Prius, from MOTORAD and CALORSTAT.

This group includes CALORSTAT RC0145, MOTORAD T51 and MOTORAD T131.

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

2 Cooling System Tester Adapter parts for the 2021 Toyota Prius come from MOTORAD.

This group includes MOTORAD 3124 and MOTORAD 3125.

This table covers the Inverter coolers. Typical signs include overheated fluid, a leak at the fittings, or mixed fluids in the reservoir. Flush the lines when you replace a cooler. Read more

One part is listed for the 2021 Toyota Prius — MOTORAD TA9225.

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

7 Radiator parts for the 2021 Toyota Prius come from 6 brands — KOYORAD, CSF, DENSO and 3 other brands. The "Popular" part is CSF 3943.

Listed part numbers: CSF 3943, KOYORAD A13591 and DENSO 2219651, plus the other parts above.

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

4 Radiator Cap parts for the 2021 Toyota Prius come from 4 brands — CALORSTAT, GATES, MOTORAD and 1 other brand.

Listed part numbers: CALORSTAT RC0047, GATES 31411 and MOTORAD T36, plus the other parts above.

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

5 Radiator Fan Assembly parts are listed for the 2021 Toyota Prius, from SKP, TECHPRO, AGILITY and 2 other brands. AGILITY 6010306 carries the "Popular" badge.

Economy: 2 parts, from SKP and TECHPRO. A representative part number is SKP SK623690.

The Standard Replacement section: 3 options from AGILITY, TYC and UAC. AGILITY 6010306 is listed in this group.

This group includes AGILITY 6010306, SKP SK623690 and TECHPRO TO3115191 and the remaining parts above.

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

6 Radiator Hose parts are listed for the 2021 Toyota Prius, from CONTINENTAL and GATES. CONTINENTAL 62765 carries the "Popular" badge.

Listed part numbers: CONTINENTAL 62765, CONTINENTAL 66029 and CONTINENTAL 66027, plus the other parts above.

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

21 Temperature Sender / Sensor parts for the 2021 Toyota Prius come from 14 brands — STANDARD MOTOR PRODUCTS, GPD, UNITED MOTOR PRODUCTS and 11 other brands. The "Popular" part is ULTRA-POWER 5S1616.

The Economy section: 6 options from GPD, UNITED MOTOR PRODUCTS, ULTRA-POWER and 1 other brand. ULTRA-POWER 5S1616 is listed in this group.

Standard Replacement: 15 parts, from STANDARD MOTOR PRODUCTS, DELPHI, BECK/ARNLEY and 7 other brands. A representative part number is ACDELCO D583.

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

8 Thermostat parts are listed for the 2021 Toyota Prius, from SKP, AISIN, MOTORAD and 5 other brands. AISIN THT017 carries the "Popular" badge.

Economy: 1 part, from SKP. A representative part number is SKP SK9025138.

The Standard Replacement section: 7 options from AISIN, MOTORAD, ACKOJA and 4 other brands. AISIN THT017 is listed in this group.

Listed part numbers: AISIN THT017, SKP SK9025138 and MOTORAD 700180, plus the other parts above.

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

7 Thermostat / Thermostat Housing / Water Outlet Seal parts for the 2021 Toyota Prius come from 4 brands — FEL-PRO, APEX, ELRING and 1 other brand. The "Popular" part is APEX AWO2047.

Part numbers include APEX AWO2047, FEL-PRO 35445 and APEX AWO2294, among others listed above.

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

2 Thermostat Housing / Water Outlet parts are listed for the 2021 Toyota Prius, from GATES and MOTORAD.

Part numbers include GATES CO35121 and MOTORAD CH2109.

This table covers the gaskets that seal the Water Inlet. 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

This group shows a single part: ELRING 775210.

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

6 Water Pump parts are listed for the 2021 Toyota Prius, from AISIN, BECK/ARNLEY, SKP and 2 other brands. AISIN WQT003 carries the "Popular" badge.

Economy: 2 parts, from BECK/ARNLEY and SKP. A representative part number is BECK/ARNLEY 1312561.

The Standard Replacement section: 4 options from AISIN, FOUR SEASONS and NISSENS. AISIN WQT003 is listed in this group.

Part numbers include AISIN WQT003, BECK/ARNLEY 1312561 and SKP SKWPT205, among others listed above.

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

4 Water Pump Gasket parts for the 2021 Toyota Prius come from 4 brands — APEX, ELRING, FEL-PRO and 1 other brand.

This group includes APEX AWP3290, ELRING 699690 and FEL-PRO 36010 and the remaining parts above.