2018 Kia Optima 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

18 Coolant / Antifreeze parts for the 2018 Kia Optima come from 6 brands — PRESTONE, VALVOLINE, PEAK and 3 other brands. The "Popular" part is FVP MV5050GAL. 14 parts fit every engine; the other 4 are engine-specific.

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, PEAK, PRESTONE 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 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, VALVOLINE, BECK/ARNLEY, AISIN and 1 other brand supply 7 parts: built to original-equipment specification. A representative part number is VALVOLINE 861398.

This table covers the Coolant Hose Connector flanges. Read more

2 Coolant Hose Connector / Flange parts for the 2018 Kia Optima come from 2 brands — AUTOTECNICA and FOUR SEASONS.

This group includes AUTOTECNICA HY0718764 and FOUR SEASONS 86362.

This table covers the gaskets that seal the Coolant Pipe. 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

One part is listed for the 2018 Kia Optima — MAHLE / CLEVITE C32833.

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

MOTORAD supplies the 4 Coolant Reservoir Cap parts for the 2018 Kia Optima. 2 parts fit every engine; the other 2 are engine-specific.

The Locking Replacement section lists 1 option from MOTORAD — grouped under the catalog's "Locking Replacement" designation — the notes column spells out what sets them apart. MOTORAD ST16R is listed in this group.

The Standard Replacement section: 1 option from MOTORAD. MOTORAD T16R is listed in this group.

2 ungrouped parts are not assigned to a grade, with the same engine-level match.

This group includes MOTORAD ST16R, MOTORAD T16R and MOTORAD T154 and the remaining parts above.

This table covers the Cooling Fan control modules. Read more

One part is listed for the 2018 Kia Optima — GATES FCM176.

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

3 Cooling System Tester Adapter parts for the 2018 Kia Optima come from 2 brands — MOTORAD and GATES. 2 parts fit every engine; the other 1 is engine-specific.

This group includes GATES 31428, MOTORAD 3121 and MOTORAD 3122.

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

7 Intercooler parts for the 2018 Kia Optima come from 3 brands — TECHPRO, GPD and TYC.

This group includes GPD 2711398, GPD 2711399 and TECHPRO KI3012104 and the remaining parts above.

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 2018 Kia Optima — TYC 13831.

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

31 Radiator parts for the 2018 Kia Optima come from 13 brands — KOYORAD, CSF, OSC and 10 other brands. The "Popular" part is ULTRA-POWER 13603. Economy and Standard Replacement are all represented, and Standard Replacement alone accounts for 21 parts.

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

6 Radiator Cap parts for the 2018 Kia Optima come from 4 brands — GATES, MOTORAD, CALORSTAT and 1 other brand. The "Popular" part is GATES 31534. 5 parts fit every engine; the other 1 is engine-specific.

Locking Replacement: 2 parts, from GATES and MOTORAD. A representative part number is GATES 31534.

Standard Replacement: 4 parts, from MOTORAD, CALORSTAT, DORMAN and 1 other brand. A representative part number is MOTORAD T16R.

This group includes GATES 31534, MOTORAD ST16R and MOTORAD T16R and the remaining parts above.

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

22 Radiator Fan Assembly parts are listed for the 2018 Kia Optima, from TECHPRO, UAC, DORMAN and 10 other brands. DORMAN 621573 carries the "Popular" badge.

Economy: 10 parts, from TECHPRO, DORMAN, GPD and 3 other brands. A representative part number is DORMAN 621573.

The Standard Replacement section: 11 options from UAC, TYC, AGILITY and 3 other brands. TYC 623750 is listed in this group.

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

This table covers the Radiator Fan blades. Typical signs include chatter, streaks, or a skip at the top of the stroke. Confirm left and right lengths in the notes — they are often different. Read more

One part is listed for the 2018 Kia Optima — HYUNDAI 252313R000.

This table covers the Radiator Fan resistors. Read more

2 Radiator Fan Resistor parts for the 2018 Kia Optima come from 2 brands — AUTOTECNICA and STANDARD MOTOR PRODUCTS. Every part fits all 4 engine options (1.6L L4 Turbocharged, 2.0L L4 ELECTRIC/GAS, 2.0L L4 Turbocharged and 2.4L L4).

Part numbers include AUTOTECNICA KI0719959 and STANDARD MOTOR PRODUCTS RY2048.

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 2018 Kia Optima, from GATES, CONTINENTAL, DAYCO and 1 other brand. GATES 24949 carries the "Popular" badge.

Listed part numbers: GATES 24949, CONTINENTAL 66691 and DAYCO 72893, 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

22 Temperature Sender / Sensor parts for the 2018 Kia Optima come from 12 brands — STANDARD MOTOR PRODUCTS, HOLSTEIN, GPD and 9 other brands. The "Popular" part is HOLSTEIN 2CTS0091. 1 part fits every engine; the other 21 are engine-specific.

The Economy section: 7 options from HOLSTEIN, GPD, UNITED MOTOR PRODUCTS and 1 other brand. HOLSTEIN 2CTS0091 is listed in this group.

Standard Replacement: 15 parts, from BECK/ARNLEY, DELPHI, STANDARD MOTOR PRODUCTS and 6 other brands. A representative part number is BECK/ARNLEY 1581695.

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

20 Thermostat parts are listed for the 2018 Kia Optima, from MOTORAD, BECK/ARNLEY, AISIN and 5 other brands. AISIN THYK805 carries the "Popular" badge.

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

16 Thermostat / Thermostat Housing / Water Outlet Seal parts for the 2018 Kia Optima come from 6 brands — FEL-PRO, APEX, MAHLE / CLEVITE and 3 other brands. The "Popular" part is FEL-PRO 35921.

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

19 Thermostat Housing / Water Outlet parts are listed for the 2018 Kia Optima, from MOTORAD, FOUR SEASONS, GATES and 2 other brands. FOUR SEASONS 86288 carries the "Popular" badge.

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

3 Water Inlet Gasket parts for the 2018 Kia Optima come from 3 brands — AJUSA, APEX and FEL-PRO.

This group includes AJUSA 01113800, APEX AWO2093 and FEL-PRO 35368.

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

22 Water Pump parts are listed for the 2018 Kia Optima, from AISIN, DAYCO, GATES and 7 other brands. US MOTOR WORKS US6247 carries the "Popular" badge.

Economy: 8 parts, from US MOTOR WORKS, BECK/ARNLEY, FVP and 1 other brand. A representative part number is US MOTOR WORKS US6247.

The Standard Replacement section: 11 options from AISIN, DAYCO, GATES and 2 other brands. AISIN WPK810 is listed in this group.

3 ungrouped parts are not assigned to a grade, with the same engine-level match.

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

12 Water Pump Gasket parts for the 2018 Kia Optima come from 6 brands — FEL-PRO, APEX, ELRING and 3 other brands. The "Popular" part is FEL-PRO 35813.

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

2 Water Pump Seal / O-Ring parts are listed for the 2018 Kia Optima, from APEX and FEL-PRO.

Part numbers include APEX AWP3203 and FEL-PRO ES72872.