Cooling System
Cooling system for the 3UZ-FE 4.3L V8 in the SC430. Aluminium engine — overheating is especially dangerous as it risks warping the cylinder heads.
Key components
- Radiator — OEM 16400-50280, plastic top tank crimped onto aluminium core. Known failure point at the plastic/aluminium joint. See Radiator Plastic Tank Crack. Best aftermarket replacement: Denso 221-3175 (OEM manufacturer, same unit without Lexus markup).
- Water pump — belt-driven. Can leak from shaft seal.
- Thermostat — standard wax-pellet type
- Radiator hoses — upper and lower. Rubber, age-related degradation.
- Coolant — Toyota Super Long Life Coolant (pink)
Known faults
- Radiator Plastic Tank Crack — primary radiator failure mode. Plastic/aluminium joint separates.
Stub — needs expansion
This page needs further research on:
- Water pump failure patterns and OEM part numbers
- Thermostat failure patterns
- Coolant capacity and service intervals
- Hose part numbers
Sources
Related
- Power Steering System (PS fluid can be mistaken for coolant — both can be pink/red)
- Front Suspension — separate system, but overheating during extended driving can accelerate rubber bushing degradation in suspension components