Can Poor Quality Engine Oil Increase Fuel Consumption?
2 Answers
Using higher quality engine oil when economically feasible benefits engine operation by reducing noise, extending engine lifespan, and enhancing safety. Higher viscosity oils offer better protection (anti-wear) due to thicker, stronger oil films. However, they consume more engine output power, making them less fuel-efficient compared to lower viscosity oils. Here’s additional information: High-viscosity oil: Following the manufacturer's recommended viscosity is the most reliable approach. Since using high-viscosity oil increases fuel consumption, there's no need to deliberately pursue the so-called "higher viscosity equals quieter operation" effect and blindly choose oils with viscosity standards higher than those recommended by the manufacturer.
After driving for so many years, I've learned it the hard way. Poor-quality engine oil can indeed sneakily increase fuel consumption, especially when running the AC in summer. Those no-name oils from small manufacturers have unstable viscosity—they thin out when the engine heats up, increasing friction between parts. The ECU then compensates for the power loss by automatically increasing fuel injection. My neighbor's old Camry burned an extra liter per 100km after switching to substandard oil. Plus, cheap oils have poor cleaning performance—sludge builds up in just three months, restricting piston ring movement and forcing the engine to guzzle more fuel. Now I always check for the API certification mark on oil cans. Only SN-grade or higher full-synthetics give me peace of mind. It's way more cost-effective than saving a few bucks on inferior oil.
