⚠️ Lexus manufacturer position
Tank module access under rear load floor on most generations. Lexus excludes contamination damage from warranty. Use ETM torque values on lock ring.
Vehicle information
| Make | Lexus |
|---|---|
| Model | RX |
| Market status | Sold new in the UK 1998–present |
| Body styles | SUV |
| Generations | XU10, XU30, AL10, AL20, AL30 (hybrid dominant in recent UK line-up) |
| Engine options | Petrol: 3.5L V6 petrol (RX 350, model years vary) Hybrid: 3.5L hybrid (RX 450h) — common UK choice |
| Fuel tank capacity | Approximately 65–72 litres depending on generation |
| Fuel system | Petrol injection with in-tank pump; hybrid shares Toyota RX/L Highlander architecture |
| Access method | Load-floor or rear-seat module access — varies by generation |
| Anti-siphon | Yes — restricted neck |
| Service portal | Lexus Electronic Technical Manual (ETM) via Lexus UK dealer |
Misfuel risk Moderate
Large SUV tank capacity increases cost of a full wrong-fuel fill. Holiday and courtesy-car use raises petrol/diesel confusion on rare diesel imports.
If the engine was not started
Do not start the engine. Leave the ignition off, avoid turning the key to ON (which can prime the fuel pump). Have the vehicle recovered to a workshop. Extract fuel from the tank and flush the fuel system using Toyota-prescribed access before attempting to start.
If the engine was started
If the engine was run on contaminated fuel, expect extended work: tank fuel extraction, new fuel filter(s), fuel line purge, and inspection of high-pressure pump and injectors per Toyota service data. Hybrid models may also need inverter cooling circuit checks if wrong fluid entered any reservoir.
Access procedure
- Relieve pressure; disconnect battery; HV off on hybrids.
- Remove load-floor trim to expose module cover.
- Disconnect fuel lines and module harness.
- Remove lock ring with Lexus-approved tool.
- Drain tank; inspect for sediment after contamination.
- New O-ring on reinstall; refill and prime.
- Check EVAP and leak codes after reassembly.
Related models
- NX
- GX (not UK new)
- Toyota Highlander/Kluger
Frequently asked questions
I filled my RX 450h with diesel by mistake — what now?
Do not crank the engine. Drain the petrol tank fully and replace the fuel filter before attempting a start.
Is the RX tank bigger than other Lexus models?
Yes — allow extra disposal capacity for contaminated fuel under UK duty-of-care rules (Environment Agency / SEPA guidance).
Need professional misfuel recovery?
Find a certified operator or read consumer guidance for your next steps.
Find an operator Consumer guidance