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Is there a big difference between 0W20 and 5W?

In brief, for most drivers the difference between 0W-20 and 5W-20 is not dramatic once the engine is at operating temperature; the main distinction lies in cold-weather performance and climate suitability.

What the numbers mean

The numbers in an oil grade encode both cold-flow ability and the oil's viscosity at high temperatures. The prefix (0W vs 5W) indicates cold-temperature performance, while the '20' indicates the viscosity at 100°C. Oils labeled 0W-20 and 5W-20 share the same high-temperature viscosity, so their behavior once the engine warms up is similar, but their cold-start characteristics differ.

Cold-start and startup protection: 0W-20 pours more easily at very low temperatures, reducing engine wear during cold starts.

High-temperature viscosity: at engine-running temperatures (around 100°C), both grades behave like a 20-weight oil, offering comparable film strength and protection.

Fuel economy and friction: in many engines, the thinner cold oil of 0W-20 can yield small efficiency gains; actual results depend on engine design and driving conditions.

Manufacturer specification: many newer engines are tuned for 0W-20, but some environments and engines still require or permit 5W-20; always follow the manual or the manufacturer's service bulletin.

With these factors in mind, the practical takeaway is that the cold-weather performance and compatibility with the engine’s design determine whether 0W-20 or 5W-20 is the better choice; otherwise, they are quite similar in normal operation.

Choosing the right grade for your vehicle

To decide which oil to use, start with the vehicle’s owner’s manual, then consider climate and driving conditions. If your manual lists both options as acceptable, you have more flexibility. If it specifies a single grade, prefer that one to preserve warranty and ensure optimal lubrication.

Follow the manufacturer’s specification first: the approved viscosity and performance standards are chosen to suit the engine’s tolerances and fuel-economy targets.

Climate and driving conditions: extremely cold climates benefit from the lower cold-start viscosity of 0W-20, while hot climates or heavy-duty use may not require a 0W-20 in some engines.

Warranty and service considerations: using a different grade than specified can affect warranty coverage; when in doubt, check with the dealer.

Substituting: if you can’t obtain the exact grade, consult an expert about permissible alternatives and any required oil-change interval changes.

The bottom line is simple: stick to the approved grade, and the difference between 0W-20 and 5W-20 will be a matter of climate and startup performance rather than daily driving quality.

Summary

The practical difference between 0W-20 and 5W-20 centers on cold-weather performance and climate compatibility. In normal, warmed-up operation, the oils behave similarly since both are 20-weight at temperature. Always use the grade specified by your manufacturer, and consult a qualified mechanic if you’re unsure.

Is there a big difference between 0W and 5W?

The 0W or 5W refers to the pumpability in cold temperatures. Therefore, a 0W would flow more easily than a 5W and could be an acceptable substitute. Thus, it is suitable to use a SAE 0W-20 as a replacement for SAE 5W-20 application. **Offers same protection as 5W but also provides faster flow and better fuel economy.

Why do dealerships give you 0W20 oil?

Modern 0W20 synthetic oil delivers a perfect balance of engine protection and efficiency. Unlike conventional oils that thicken significantly in cold weather, 0W20 maintains consistent viscosity across temperature extremes.

Should I use 0W-20 in hot weather?

Yes, 0W-20 oil is generally good for hot weather, provided your car's manufacturer specifies it and you follow maintenance intervals, as high-quality synthetic oils are designed to handle a wide temperature range. However, in some extreme hot climates, especially with high mileage or frequent heavy loads like towing, a heavier oil like 5W-30 may be better. Always refer to your owner's manual to determine the correct oil for your specific vehicle and driving conditions.
Factors to consider

Manufacturer's recommendation: Your car's owner's manual is the ultimate guide. If it specifies 0W-20, that is the oil the engine was designed for, even in hot climates.
Modern engines: Many modern engines are designed with tighter tolerances, and some manufacturers recommend 0W-20 for fuel economy and efficient operation, even in warm climates.
Quality of the oil: Full synthetic 0W-20 oils are formulated to perform well in both cold and hot weather extremes, maintaining protection across a wide temperature range.
Extreme conditions: If you live in a consistently very hot climate (e.g., exceeding 100∘100 raised to the composed with power100∘F or 38∘38 raised to the composed with power38∘C) and frequently tow heavy loads, you might consider a slightly thicker oil like 5W-30 during the summer months, as it provides a thicker oil film for added protection in high-stress situations.
High mileage vehicles: Older engines with high mileage may benefit from the thicker oil film of a 5W-30 to help protect worn components, especially in hot weather.
Engine temperature: A properly functioning cooling system will keep engine temperatures regulated. The issue is typically overheating, not the oil itself, so ensure your cooling system is in good shape.

Is there a big difference between 0W-20 and 5W-20?

Yes, there is a difference: 0W-20 oil flows more easily in very cold temperatures than 5W-20, providing better cold-start protection. The "0W" rating indicates a lower viscosity in cold conditions, while the "5W" indicates it is slightly thicker at startup. At normal operating temperatures, both oils have the same viscosity (the "20" in their name), meaning they offer the same level of protection once the engine is warm.

Feature	0W-20	5W-20
Cold Viscosity	Thinner, flows more easily and quickly at startup in freezing temperatures	Thicker than 0W-20 in cold temperatures, circulates slightly slower at startup
Operating Temperature	Thinner at operating temperature, same as 5W-20	Thicker than 0W-20 at operating temperature, same as 0W-20
Best Use Case	Extremely cold climates, modern engines, turbochargers	Milder or moderate winter climates
Price	Typically slightly more expensive	Often more budget-friendly

Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.