2025 Lexus GX550 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

14 Coolant / Antifreeze parts are listed for the 2025 Lexus GX550, from PRESTONE, VALVOLINE, AISIN and 1 other brand. VALVOLINE ZXG051 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, PRESTONE and VALVOLINE supply 2 parts: the catalog's value-priced group. A representative part number is PRESTONE AF3100.

The Heavy Duty section lists 2 options from VALVOLINE and PRESTONE — rated for severe service. VALVOLINE ZXG051 is listed in this group.

The Premium section lists 3 options from PRESTONE — 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 VALVOLINE, AISIN and PENTOSIN — built to original-equipment specification. AISIN ACT002 is listed in this group.

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 2025 Lexus GX550 come from 3 brands — CALORSTAT, GATES and MOTORAD.

Listed part numbers: CALORSTAT RC0145, GATES 31541 and MOTORAD T51.

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

3 Radiator Fan Clutch parts are listed for the 2025 Lexus GX550, from FOUR SEASONS, HAYDEN and US MOTOR WORKS.

Listed part numbers: FOUR SEASONS 46159, HAYDEN 3350 and US MOTOR WORKS 22365.

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

4 Temperature Sender / Sensor parts are listed for the 2025 Lexus GX550, from GPD, STANDARD MOTOR PRODUCTS, WELLS and 1 other brand.

Economy: 1 part, from GPD. A representative part number is GPD 1814549.

The Standard Replacement section: 2 options from STANDARD MOTOR PRODUCTS and WELLS. STANDARD MOTOR PRODUCTS TX319 is listed in this group.

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

Part numbers include GPD 1814549, STANDARD MOTOR PRODUCTS TX319 and WELLS 5S17570, 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

3 Thermostat parts for the 2025 Lexus GX550 come from 3 brands — AISIN, JAPANESE OE and MOTORAD.

Part numbers include AISIN THT027, JAPANESE OE WHTYJ82 and MOTORAD 1450180.

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

4 Water Pump parts for the 2025 Lexus GX550 come from 3 brands — FVP, GMB and US MOTOR WORKS.

Listed part numbers: FVP 1704230 and FVP US8239, plus the other parts above.