2026-07-21 · 4 min read
Toyota Vellfire Inverter Coolant — Hybrid-Only Maintenance Guide
Vellfire hybrid has a separate inverter coolant circuit most workshops overlook. Neglecting it risks inverter overheating — a RM 5,000+ repair. What to use and when to change it.
Vellfire Inverter Coolant — The Forgotten Fluid
The inverter coolant circuit on the Vellfire is separate from the engine coolant circuit — it cools the power control unit (PCU), inverter, and DC-DC converter. Most workshops — including many Toyota dealers — service only the engine coolant and ignore this circuit. The recommended interval is every 80,000 km or 4 years. Neglected inverter coolant becomes acidic and causes internal corrosion of the PCU heat exchanger, leading to expensive hybrid system failures.
What to Ask Your Workshop
- Ask specifically: 'Please check and service the inverter coolant circuit, not just the engine coolant'
- Toyota Genuine Inverter Coolant (pink) — do not substitute with generic long-life coolant
- Cost to flush inverter circuit: RM 150–250 at our Bandar Sri Damansara workshop
- Interval: every 80,000 km or 4 years — do not skip