Symptoms
Seepage or crust at the water pump weep hole, often found at a routine service, and a coolant level that slowly drops. Owners have reported leaks from about 28k to 100k+ miles.
The fix, step by step
- Drain the coolant from the radiator petcock (driver's side, underneath).
- Remove the fan and shroud, then the drive belt.
- Unbolt the pump, clean the mating surface and fit the new pump with its gasket.
- Replace the belt while it's off.
- Refill with pink Toyota Super Long Life coolant, not red, and bleed the system.
Tools & part numbers
- Basic metric sockets
- slim 10 mm wrench for the fan nuts
- water pump 16100-09525
- drive belt 90916-A2033
- about 2 gal Toyota SLLC (pink)
Where to buy the parts
Water pump, 2015 GX 460RockAuto ↗Amazon ↗
Water pump gasket, 2015 GX 460RockAuto ↗Amazon ↗
Thermostat, 2015 GX 460RockAuto ↗Amazon ↗
Coolant, 2015 GX 460RockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Lexus GX 460 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.