The 2009 Lexus GS350 uses synthetic 5W-30 engine oil, with about 6 quarts needed for a full change. Use a high-quality oil that meets API SN or higher and ILSAC GF-5 or higher, and follow the regular maintenance interval for oil changes.
Oil specifications for the 3.5L V6
Below are the official specs and practical guidance commonly followed by owners of this model year.
What to look for when buying: viscosity, synthetic formulation, and the right certification standards determine performance and protection.
- Viscosity: 5W-30
- Oil type: Synthetic engine oil
- Certifications/standards: API SN (or higher) and ILSAC GF-5 (or higher)
- Oil capacity: Approximately 6 quarts (including the oil filter)
- Change interval: About every 5,000 miles under normal driving; more often under severe conditions
In practice, always confirm the current recommendations in the owner's manual or with a Lexus service advisor, as intervals and specs can vary by region or service history.
Climate considerations
The standard recommendation of 5W-30 synthetic is designed to work across a wide temperature range typical of many markets. For extreme climates, Lexus suggests following the manual or consulting a dealer to tailor oil viscosity and service intervals to your driving conditions.
Cold-weather guidance
In very cold climates, the 5W-30 viscosity helps with cold starts and protection on startup. If your region experiences prolonged subzero temperatures, verify that 5W-30 remains the recommended grade in the owner's manual and consider service advisories for interval adjustments.
Hot-weather guidance
In hot climates or heavy driving, synthetic 5W-30 provides protection during high-temperature operation. Regularly check oil level, and adhere to the standard 5,000-mile change interval unless your driving pattern warrants earlier changes as advised by Lexus.
Summary
For the 2009 Lexus GS350, the standard oil choice is synthetic 5W-30, with a typical fill of about 6 quarts and a maintenance interval near 5,000 miles. Always verify the exact specifications and service intervals for your vehicle with the owner’s manual or a Lexus service professional, particularly if you operate in extreme temperatures or have a nonstandard driving regime.