0W20 and 5W20 are winter-grade oils designed for cold weather. They allow your engine to perform at its highest efficiency, and are very similar when compared. So, you may be wondering how they differ. What’s the difference between SAE 0W-20 and 5W-20 motor oils?
Both oils are very similar, except for their composition and the lowest temperature at which they can flow. While both are low-temperature grade motor oils, 0W20 is slightly better to use in extremely cold weather.
This article will define viscosity grades and give you tips on the right circumstances when to properly use each oil type. You will also learn about motor oil blends and find answers to common questions. Read on so that you can make the distinction between 0W20 vs 5W20.
Oil Viscosity Defined
Oil viscosity refers to the resistance of a liquid to flow at a specific temperature. Thin oils pour more easily at low temperatures than thicker oils that have a higher viscosity. Thin oils are usually winter-grade as they reduce friction in engines and help them start quickly at cold temperatures. Thick oils, fondly called summer-grade oils, maintain better film strength and oil pressure at high temperatures and loads and seal better.
In 1911, the Society of Automotive Engineers or SAE established a numerical code system (SAE J300) for grading oils based on their viscosity characteristics. Motor oils were originally all mono-grades because oil manufacturers always had to start with thick oil to get the right thickness at operating temperatures. Eventually, additive technology, which made it possible for oil to thin more slowly, allowed a selection of thinner oil to start from in determining film thickness. The format for a viscosity classification is XW-XX – where X is the cold operating viscosity and W meaning winter, and XX is the hot operating viscosity of the motor oil.
Single-Grade vs Multi-Grade Oil
There are two kinds of viscosity grades – single-grade and multi-grade. For single-grade motor oils, there are 11 viscosity grades in total: 0W, 5W, 10W, 15W, 20W, 25W for low-temperature grades, and 20, 30, 40, 50, and 60 for high-temperature grades. This type cannot use viscosity modifiers and are often called straight-weight oils. On the other hand, multi-grade motor oils have special polymers added that allows them to perform in a wide range of temperatures. This type would have the viscosity of the base grade when cold and of the second grade when hot. For example, an SAE 5W20 oil would be a product that acts like an SAE 5 at cold temperatures (5W for winter) and like an SAE 20 at 100 °C (212 °F).
This viscosity table below from Anton Paar summarizes the different viscosity levels for both low and high-temperature motor oils. The figures in red are recent updates to the SAE J300 system since April 2, 2013 – the total viscosity grades now becoming 14:
|SAE Viscosity Grade[°C]||Min. Viscosity [mm²/s] at 100 °C||Max. Viscosity [mm²/s] at 100 °C||High Shear Rate Viscosity [mPa.s] at 150 °C||Cranking Viscosity|
[mPa.s] max. at Temp. [°C]
|Pumping Viscosity [mPa.s] max. at Temp. [°C]|
|0W||3.8||—||—||6200 at -35°C||60 000 at -40°C|
|5W||3.8||—||—||6600 at -30°C||60 000 at -35°C|
|10W||4.1||—||—||7000 at -25°C||60 000 at -30°C|
|15W||5.6||—||—||7000 at -20°C||60 000 at -25°C|
|20W||5.6||—||—||9500 at -15°C||60 000 at -20°C|
|25W||9.3||—||—||13 000 at -10°C||60 000 at -15°C|
|40||12.5||<16.3||3.5 (0W-40, 5W-40 & 10W-40 grades)|
3.7 (15W-40, 20W-40, 25W-40 & 40 grades)
Before you get too overwhelmed with all these numbers, don’t worry as we are not going to go through all motor oil grades. We are only going to discuss the 0W20 and the 5W20 variants.
0W 20 Oil vs 5W20 Explained
0W20 motor oil (0W20 oil) is one of the low-temperature grades added to the SAE J300 EOVC system after 1952. It is liquid engineered to flow as smoothly as an SAE 0 in sub-zero weather, yet act as an SAE 20 once the engine has achieved its full operating temperature. This type of oil will still crank at -35°C/-31°F and flow through engine oil ways immediately. This oil provides lubrication to critical engine parts, making it easier for you to cold-start your engine during winter.
0W20 vs 5W20 Fuel Economy
5W20 motor oil is another low-temperature grade typically recommended for winter use, with a 10W-30 as an alternative for higher temperatures. This oil type is common because it provides the best fuel economy, saves fuel consumption, and has fewer exhaust emissions. 5W20 is sought globally by motor manufacturers and governments – led by Japan, Europe, and the U.S.
Both 0W20 and 5W20 are low viscosity and high-quality synthetic grades that can massively optimize fuel economy. Their properties are the same when used in fair-weather temperatures. Likewise, there is little to no difference between the two versions when used in cold conditions.
When to Use 0W20 vs 5W20
Below are some considerations when deciding to use either of the two oils:
- Your Owner’s Manual. Referring to your owner’s manual is quite simple yet often overlooked. Always check your owner’s manual to see the recommended viscosity of the motor oil you need to use. If both 0W20 and 5W20 variants are on the list, use them alternately without hesitation, depending on weather conditions.
- Location. It is crucial to consider where you use the vehicle as both 0W20 and 5W20 motor oils fall within almost the same temperature spectrum. 0W-20 synthetic oil’s range is between -40°C to 20°C while a 5W20 (5W20 synthetic oil) is from -35°C to 20°C. Knowing these details means two things:
- It is better to use 0W20 oil if you live in a place with very cold temperatures, such as Alaska or Maine.
- You cannot use either 0W20 or 5W20 in areas where temperatures exceed 20°C/68°F like Florida.
- Viscosity. The smaller the number, the better the motor oil will flow. A 0W20 will be more fluid than a 5W20 at startup temperatures but will perform the same way at standard engine operating temperatures. Remember, engine oils naturally thicken as they cool down and thin as they are heated. In this video, Nolan McKinney does a cold pour test between a 30W, 5W20, and 0W20. He recommends using the 0W20 out of the three.
- Quality Testing. Choose any oil brand with the right viscosity grade that displays the starburst symbol and the API donut. The starburst symbol shows that the oil has passed the tests listed for SL service. The API donut means that the American Petroleum Institute tested your motor oil and met the current SL service rating. The European equivalent of API is ACEA (Association des Constructeurs Europeens d’Automobiles)
- Manufacturer Requirements. Customarily, the machine designer would recommend a motor oil with high viscosity and is heavy like honey if your vehicle is heavily loaded. But if it runs very fast, a lubricant that can get out of the way and back just as quickly is more suitable.
- Fuel Economy. Although 5W20 and 0W20 (0W20 synthetic oil) can be used at 20°C/68°F, 0W20 is thinner than 5W20 with cold engine temperatures, especially during the first few minutes after you start your car. New cars specify it because it gives the car a bit better fuel economy compared to the 5W20. The 0W20 variant also meets the demands of a turbo-diesel engine.
Mixing 0W20 with 5W20
There are mixed reactions when enthusiasts and motor oil savants are asked if this is possible. Most experienced mechanics and vehicle owners err on the side of caution and are wary of mixing 0W20 with 5W20 oil. SAE 0 oils are full-synthetic oils, whereas 5W20 might be partially synthetic or conventional. Even if your 0W20 and 5W20 variants are 100% synthetic, the next thing you may need to worry about is warranty and fuel consumption. Not to mention that 0W20 is very thin and specified for modern engines (made within the last ten years) with tight tolerances for better efficiency. Check the stuff you are planning on mixing to ensure compatibility and consult your owner’s manual about what kind of oil grade it permits.
Unless it’s the only oil you have on hand and an emergency, it would be safer for you to stay away from mixing the two variants or even interchanging them. The SAE J300 specifications indicate maximum viscosity, so a 0W20 oil will always comply with a 5W20. But blending them will almost certainly make the blend fail the -35°C test. Even if this weren’t the case, both 0W20 and 5W20 may contain different additives that may break free any long-standing contaminants that the usual motor oil would leave behind throughout the engine. It could easily spell trouble when this happens.
Motor Oil Blends
Since I have talked about 0W20 and 5W20 having different additives that may not be compatible when put together, it would be beneficial for you to know the different oil blends and to which category each variant belongs to:
- Premium Conventional Oil. This mineral oil is standard for new cars and covers just about every simple engine design and light-duty vehicle. Service level SM is the current designation and is available in a variety of viscosity grades. Any rating older than SJ is already obsolete.
- Full Synthetic Oil. The oil is compatible with high-tech engines like Corvettes and Mercedez-Benz vehicles, have superior, longer-lasting performance in all the critical areas, and are not meant for all engine types. They are also expensive. All 0W20 motor oils are full-synthetic. There are some 5W-30 oil grades like Pennzoil (550038221-3PK) Platinum 5W-30 Full Synthetic Motor Oil GF-5 (view on Amazon) that belong to this type of blend.
- Synthetic Blend Oil. This has a dose of synthetic oil mixed with organic oil, making it less volatile. Using this type reduces oil loss and increases fuel economy. They’re excellent for towing and off-roading and often used for pickups or SUVs that need high-load protection. They’re a lot less expensive than full-synthetic oils and priced just a bit more than a premium conventional oil. At best, all 5W20 motor oils like Royal Purple 05520 API-Licensed SAE 5W-20 High Performance Synthetic Motor Oil (view on Amazon) are a synthetic blend.
- Higher-Mileage Oil. This caters to older vehicles with more than 75,000 miles on the odometer. It consists of seal conditioners that flow into the seal’s pores to restore their shape and increase their flexibility. They seal piston-to-cylinder clearances better and have a higher dose of viscosity improvers and anti-wear additives to try to slow the wear process.
- Does 0W20 damage the engine? If used on an engine that works with 5W20, it will improve fuel efficiency as it has less drag at the crankshaft and is better at startup during cold temperature. But if used to replace a 5W-30, it will be detrimental to your engine.
- Can 5W30 be used instead of 0W20? Although 5W-30 is a fantastic crossover between a high-mileage and full-synthetic oil, if your vehicle specifications say 0W20, it is best to go with that recommendation.
- Will 5W20 hurt a 0W20 engine? If the outside temperature is way below -30°C, then it could damage a 0W20 engine. Not to mention that since 5W20 is a synthetic blend, it may have additives that could be harmful or incompatible with that of 0W20 motor oil.
- What happens if I use the wrong viscosity or engine oil? Oil leakage, reduced mileage, noisy engine, cold-start problems, and burnt oil are just some things that could happen. You wouldn’t want the manufacturer to refuse the warranty because you used the wrong oil, which became the cause of an engine failure. In this video by Auto Learn shows proof that these problems will happen if you put the incorrect engine oil in your vehicle.
- Is it okay for me to switch oil brands? Yes, it is! However, make sure to choose an oil brand marked with the same API donut level as what you have used in the past. Also, follow your owner’s manual recommendations for API category and viscosity.
- Can I use 5W20 instead of 0W20 for Honda cars? It depends on what specific Honda engine you have. If you have, say, the Civic Hybrid, then 0W20 oil is preferred by the manufacturer, with 5W20 as an alternative if 0W20 is not available. But if you have a 2011 Honda Accord, then 5W20 is still recommended.
- Why does Toyota recommend 0W20 for their engine? The main reasons behind Toyota’s recommendation for 0W20 have to do with lubrication, engine efficiency and protection, and emissions. 0W20 has the perfect cold-start viscosity and helps your engine reach its operating temperature the fastest, even when the cold temperature makes it inefficient. It reduces startup wear and incomplete emissions and optimizes fuel efficiency. It also assures Toyota that the oil you’re using can withstand the oil change interval they recommend.
- Should I use 0W20 or 5W20 for a Toyota Camry? Follow what’s in your owner’s manual as the manufacturer knows your engine’s requirements in and out better than any mechanic. For instance, if you have a 2009 Toyota Camry Hybrid, your owner’s manual should recommend a 0W20 as your primary lubricant and 5W20 as an alternative.
Conclusion – 0W20 vs 5W20: What’s the Difference?
The distinction between 0W20 and 5W20 motor oils may be almost negligible for the average Joe. But for savvy vehicle owners and mechanics, it is worth taking notice. Choosing the right oil is crucial in the safe-keep and maintenance of your vehicle, as it acts as a lubricant, a heat pump, a magnet for combustion products, and a shield against engine corrosion. As it is your engine’s lifeblood, you should take great care and make sure to use only the recommended oil stated in your owner’s manual or as specified by your manufacturer.