We Ran 0W-20, 5W-30 & 5W-40 in the Same Engine — The Results Surprised Us

We tested three motor oil viscosity grades in identical engine conditions to reveal which truly protects best—and the results challenge everything you thought you knew about manufacturer recommendations. Discover why the difference between 0W-20, 5W-30, and 5W-40 could mean the difference between an engine that dies at 120,000 miles and one that survives past 400,000 miles. This comprehensive oil testing comparison reveals which viscosity grade delivers superior engine protection in real-world driving. Understanding motor oil viscosity is crucial for engine longevity—the first number (with "W" for Winter) indicates cold-start flow performance, while the second number shows how your oil protects at operating temperature around 212°F. In our head-to-head engine oil test, we evaluated 0W-20's lightweight protection, 5W-30's balanced performance, and 5W-40's thicker viscosity on the same engine with identical driving cycles and service intervals. Watch as we reveal what those viscosity numbers actually mean, break down the test results, and identify the clear winner that provides maximum engine protection while minimizing wear and extending engine life. Instagram Neogear0 Facebook Neo Gear