The basic answer is that both the 2.5-liter four-cylinder and the 3.5-liter V6 in the 2009 Altima use 5W-30 engine oil, and you can choose either conventional or synthetic oil as long as it meets the specified standards. Always check the owner's manual or the under-hood label for your exact engine and climate needs.
Two engines, one oil standard
The 2009 Altima was offered with two engines: a 2.5-liter four-cylinder (QR25DE) and a 3.5-liter V6 (VQ35DE). For normal operation, Nissan specifies 5W-30 engine oil for both engines, and the oil can be conventional or synthetic. The oil should meet current API service requirements and ILSAC ratings. The specifics vary slightly by engine, so review the details below for your model.
2.5-liter four-cylinder (QR25DE)
Oil specifications for the QR25DE engine are summarized here:
- Viscosity: 5W-30
- Oil type: Conventional or synthetic acceptable
- API service: SN (or newer)
- ILSAC rating: GF-4 or newer (GF-5 recommended for newer oils)
- Oil capacity (with filter): roughly 4.0–4.5 quarts
In short, the QR25DE calls for 5W-30 oil, with either conventional or synthetic formulations, depending on your preference and climate.
3.5-liter V6 (VQ35DE)
Oil specifications for the VQ35DE engine are as follows:
- Viscosity: 5W-30
- Oil type: Conventional or synthetic acceptable
- API service: SN (or newer)
- ILSAC rating: GF-4 or newer (GF-5 recommended for newer oils)
- Oil capacity (with filter): roughly 5.0–5.5 quarts
The V6 shares the same basic oil grade as the four-cylinder, just with a slightly larger oil capacity.
General notes and practical tips
Always verify the exact requirements for your vehicle by checking the hood label and the owner’s manual. If you live in extreme temperatures or you drive aggressively, consult a Nissan service advisor to confirm whether any climate-specific adjustments are recommended, such as a different viscosity.
Summary
For the 2009 Nissan Altima, use 5W-30 engine oil for both the 2.5L QR25DE and the 3.5L VQ35DE engines. Conventional or synthetic oil is acceptable, provided it meets API SN (or newer) and ILSAC GF standards. Always confirm the exact specifications for your vehicle with the owner’s manual or a Nissan dealer.