How much and what kind of oil does an onan 4kW generator use?

An Onan 4kW generator typically uses 10W-30 or 15W-40 engine oil, depending on the manufacturer's recommendations. The oil capacity is usually around 1.5 to 2 quarts (1.4 to 1.9 liters). It's important to check the specific model's manual for precise oil type and capacity, as variations may exist. Regular oil changes are essential for optimal performance and longevity.