1990 Infiniti Q45 Oil Type & Capacity: 5W-30 (6.4 quarts)
The 1990 Infiniti Q45 takes 5W-30 motor oil — 6.4 quarts with a filter change, per the factory service manual.
Factory-spec answer
5W-30 — 6.4 quarts with filter
Oil capacity by engine
| Engine | Oil Type (viscosity) | Capacity w/ Filter | Capacity w/o Filter | Notes |
|---|---|---|---|---|
| Q45 — 4.5L Eng | API - SAE 5W-30 (Below 50Deg.F), 10W-30/40 (Above 0Deg.F) | 6.40 QTS. | 5.80 QTS. | — |
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More factory specs & repair guides for your Q45
🛞 1990 Infiniti Q45 Tire Size & Pressure →🌧️ 1990 Infiniti Q45 Wiper Blade Sizes →💡 1990 Infiniti Q45 Light Bulb Sizes →📖 1990 Infiniti Q45 Factory Service Manual →All fluid capacities (transmission, coolant, brakes)Powered by factory manual data from our partner network AllOEMManuals.com.
Coolant capacity
10.8 quarts (10.22 L) — Ethylene Glycol Antifreeze Coolant
Frequently asked questions
What type of oil does a 1990 Infiniti Q45 take?
The 1990 Infiniti Q45 takes 5W-30 motor oil (API - SAE 5W-30 (Below 50Deg.F), 10W-30/40 (Above 0Deg.F)), per the factory service manual.
What is the oil capacity of a 1990 Infiniti Q45?
The 1990 Infiniti Q45 oil capacity is 6.4 quarts with a filter change, or 5.8 quarts without changing the filter.
How often should I change the oil in my 1990 Infiniti Q45?
Most 1990 Infiniti Q45 owners follow a 5,000–7,500 mile interval with conventional oil, or up to 10,000 miles with full synthetic. Always check the oil life monitor if equipped, and consult your owner's manual — Infiniti recommends intervals based on driving conditions, not just mileage.
Can I use synthetic oil in my 1990 Infiniti Q45?
Yes. 5W-30 is widely available as a full synthetic, and synthetic is safe (often recommended) for the 1990 Infiniti Q45. What matters most is matching the factory viscosity and specification, then changing the oil and filter on schedule.