2021 Toyota Prius Prime 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 are listed for the 2021 Toyota Prius Prime, from PRESTONE, PEAK, AISIN and 4 other brands. 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, PEAK and PRESTONE supply 3 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 8 options from AISIN, VALVOLINE, BECK/ARNLEY and 2 other brands — built to original-equipment specification. AISIN ACT002 is listed in this group.

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

This group shows a single part: 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 for the 2021 Toyota Prius Prime come from 2 brands — 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

MOTORAD supplies both parts for the 2021 Toyota Prius Prime.

Part numbers include 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

This group shows a single part: 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

8 Radiator parts are listed for the 2021 Toyota Prius Prime, from KOYORAD, GPD, CSF and 4 other brands. CSF 3943 carries the "Popular" badge.

Economy: 1 part, from GPD. A representative part number is GPD 13869C.

The Standard Replacement section: 7 options from KOYORAD, CSF, DENSO and 3 other brands. CSF 3943 is listed in this group.

Listed part numbers: CSF 3943, GPD 13869C and KOYORAD A13591, 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 are listed for the 2021 Toyota Prius Prime, from 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 for the 2021 Toyota Prius Prime come from 5 brands — ULTRA-POWER, GPD, TECHPRO and 2 other brands. The "Popular" part is ULTRA-POWER 624530.

The Economy section: 3 options from ULTRA-POWER, GPD and TECHPRO. ULTRA-POWER 624530 is listed in this group.

Standard Replacement: 2 parts, from AGILITY and TYC. A representative part number is AGILITY 6010471.

Listed part numbers: ULTRA-POWER 624530, GPD 2812062 and TECHPRO TO3115212, plus the other 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 for the 2021 Toyota Prius Prime come from 2 brands — CONTINENTAL and GATES. The "Popular" part is CONTINENTAL 62765.

Part numbers include CONTINENTAL 62765, CONTINENTAL 66029 and CONTINENTAL 66027, among others listed 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

17 Temperature Sender / Sensor parts are listed for the 2021 Toyota Prius Prime, from DELPHI, STANDARD MOTOR PRODUCTS, BECK/ARNLEY and 10 other brands. ULTRA-POWER 5S1616 carries the "Popular" badge.

Economy: 3 parts, from ULTRA-POWER, GPD and HOLSTEIN. A representative part number is ULTRA-POWER 5S1616.

The Standard Replacement section: 14 options from DELPHI, STANDARD MOTOR PRODUCTS, BECK/ARNLEY and 7 other brands. DELPHI TS10289 is listed in this group.

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 for the 2021 Toyota Prius Prime come from 8 brands — SKP, AISIN, MOTORAD and 5 other brands. The "Popular" part is AISIN THT017.

The Economy section: 1 option from SKP. SKP SK9025138 is listed in this group.

Standard Replacement: 7 parts, from AISIN, MOTORAD, ACKOJA and 4 other brands. A representative part number is AISIN THT017.

This group includes AISIN THT017, SKP SK9025138 and MOTORAD 700180 and the remaining 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

6 Thermostat / Thermostat Housing / Water Outlet Seal parts are listed for the 2021 Toyota Prius Prime, from FEL-PRO, APEX and VICTOR REINZ. APEX AWO2047 carries the "Popular" badge.

Listed part numbers: APEX AWO2047, FEL-PRO 35445 and APEX AWO2294, plus the other parts above.

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

2 Thermostat Housing / Water Outlet parts for the 2021 Toyota Prius Prime come from 2 brands — GATES and MOTORAD.

Part numbers include GATES CO35121 and MOTORAD CH2109.

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 for the 2021 Toyota Prius Prime come from 5 brands — AISIN, BECK/ARNLEY, SKP and 2 other brands. The "Popular" part is AISIN WQT003.

The Economy section: 2 options from BECK/ARNLEY and SKP. BECK/ARNLEY 1312561 is listed in this group.

Standard Replacement: 4 parts, from AISIN, FOUR SEASONS and NISSENS. A representative part number is AISIN WQT003.

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

3 Water Pump Gasket parts are listed for the 2021 Toyota Prius Prime, from APEX, FEL-PRO and MAHLE / CLEVITE.

Part numbers include APEX AWP3290, FEL-PRO 36010 and MAHLE / CLEVITE K32737.