What is the difference between 5w30 and 5w20?

[SanBrantley]

5w30 and 5w20 have the following differences: 1. Different oil viscosity: mainly the high-temperature viscosity of the oil. 5w20 has lower viscosity (between 5.6-9.3), which is relatively fuel-efficient and makes the vehicle feel lighter during driving, while 5W-30 has higher viscosity (between 9.3-12.5), which is relatively more fuel-consuming and makes the throttle feel heavier, but the engine noise is smaller. 2. Different sealing performance: the higher the viscosity, the better the sealing performance. The number after W in 5w30 and 5w20 represents the high-temperature viscosity, so 5w30 oil has better sealing performance than 5w20 oil. However, higher viscosity is not always better because the higher the viscosity, the greater the friction, and the greater the engine power loss.

[DiMaverick]

I've been in the auto repair industry for over a decade and have personally changed countless engine oils. The core difference between 5W30 and 5W20 lies in their high-temperature performance: the '20' after the W in 5W20 indicates it's thinner and flows faster, saving fuel but potentially offering insufficient protection at high RPMs or in hot weather; 5W30's '30' means it's slightly more viscous, thicker when the engine is hot, and better at handling load, making it suitable for older cars or tropical regions. Both start with W5 for cold starts, so there's no difference in winter sub-zero conditions. The problem is, in my repair work, I've seen many car owners blindly switch oils—20 oil saves 2-3% on fuel, but accelerates engine wear; the manual is the gold standard, and using lower viscosity oil improperly may lead to premature repairs. Based on experience, city cars can use 20 without issues, while off-road or high-displacement vehicles are better off with 30—don't save small money only to lose big money.

[LaIvan]

I've been driving a compact commuter car for three years and personally tested two types of oil. The 5W20 runs smoothly and saves fuel, cutting my monthly urban driving fuel costs by dozens of yuan. The 5W30 is thicker, providing more stable engine performance at high speeds or uphill climbs with less risk of overheating. The difference lies in the number after the W: 20 and 30 represent high-temperature viscosity. The 20 flows faster with higher efficiency but may not handle heavy loads as well. Both perform equally well in cold starts, thanks to the W5 rating for quick winter starts. Always prioritize the manual's recommendation—I use 20 for my newer car for peace of mind. For older engines or frequent long-distance driving, I switch to 30 for added safety. Maintain consistent oil change intervals and match the oil to your engine's needs for longevity—don’t just chase savings at the expense of maintenance.

[IslaLynn]

As an environmental advocate, I focus on the impact of daily choices. 5W20 reduces internal engine friction due to its low viscosity, lowering fuel consumption by approximately 2-3%, thereby aiding emission reduction and environmental protection. 5W30, with higher viscosity, consumes slightly more fuel and leaves a slightly larger carbon footprint. The key difference lies in the number after the 'W': 20 offers high efficiency and good fluidity, while 30 provides stronger protection but lower energy efficiency. Both perform the same in cold starts (W5). If your vehicle is compatible, opt for 20-grade oil and pair it with economical driving habits like gradual acceleration to further save energy. Small details in oil selection make a big difference—support the green transition by starting with small actions, ensuring engine health without wasting resources.

[VonRhett]

Share some fun facts about engine oil! The 'W' in 5W stands for winter characteristics, and the initial number 5 indicates consistent cold-start lubrication performance. The key difference lies in the suffix—20 or 30—which represents high-temperature viscosity ratings. A 20-grade oil is thin like gauze, offering fuel efficiency and smoothness, while a 30-grade is thick like armor, providing stronger protection. Using 20-grade for daily commutes saves fuel and money but isn't suitable for sustained high RPMs or engines in hot climates; 30-grade withstands summer heat and heavy loads without wear. Regional factors matter greatly: northern regions can use either, but southern tropical areas are advised to opt for 30-grade for stability. Always match your vehicle manual's recommendation and avoid mixing oils. A maintenance tip is to change oil regularly to preserve performance—keeping your engine running smoothly for a long lifespan.