Whether older car models are suitable for using 5W30 engine oil requires comprehensive evaluation based on engine wear condition, operating environment, and manufacturer recommendations. For vehicles with over 100,000 kilometres mileage showing significant wear or oil consumption issues, high-viscosity oils like 5W40 are recommended due to their superior high-temperature oil film stability, which effectively fills component clearances and enhances sealing - particularly suitable for hot climates or high-load conditions. Conversely, well-maintained older vehicles without noticeable wear operating in temperate climates benefit more from 5W30's advantages in low-temperature fluidity and fuel efficiency, reducing cold-start wear and optimizing fuel consumption. Special attention should be paid to turbocharged engines or older European models, which typically require higher viscosity oils, while lower-mileage older Japanese/Korean vehicles may be better suited for 5W30. Although more expensive, full synthetic oil's oxidation resistance and detergency offer significant advantages for prolonging older engine lifespan.
