What happens if you use 20w 50 motor oil when you should have used 10w 30?

Using 20W-50 motor oil instead of 10W-30 can lead to poor engine performance, especially in colder temperatures. The higher viscosity of the 20W-50 oil may not flow as easily during startup, potentially causing increased wear and tear on engine components. Additionally, it may not provide adequate lubrication and protection at operating temperatures, leading to overheating or reduced efficiency. Always refer to your vehicle’s owner manual for the recommended oil viscosity to ensure optimal performance.