Last Updated on 6 months by Ollie Barker
Do you know the difference between oil weights? If not, don’t worry! I’ve got you covered. This post is going to answer your burning question: Can you mix 5w20 and 5w30? How does this mix affect the engine?
The short answer is YES, you can mix 5w20 & 5w30 given that they’re from the same brand and API. However, experts still don’t recommend it as the engine can’t reach its peak performance with mixed oils.
The below explanation will let you know why we can do that.
Table of Contents
Understanding Viscosity of Oils
Oil weight refers to a measurement of viscosity, which is a lubricant’s resistance to flow at a given shear rate. Viscosity matters because it dictates an oil’s ability to protect your engine against wear and tear. Viscosity is also what helps an oil clean your engine’s surfaces.
Let’s start with the numbers. The 5w20 is the designation of a viscosity that ranges between 10,000 cSt (centistokes) to 14,000 cSt (centistokes). The 5w30 is the designation of a viscosity between 15,000 cSt (centistokes) to 20,000 cSt (centistokes). This means 5w30 operates on a higher range of thickness than 5w20.
How Are These Two Oil Viscosities Different?
The 5w30 designation refers to the base oil viscosity, which is 10% thicker than the standard 5w20. For example, a 5w30 motor oil has an API GL-5 rating, but the same base oil could have an API SN GL-4 rating. These are just examples since there are other classification systems used in motor oils, but they’re common ones.
Even though they’re called “w” weights, these numbers don’t actually refer to weight at all. Instead, the w stands for winter. “Winter” motor oils are designed to handle longer periods of cold weather and protect against engine wear from starts and stops in cold weather. So basically, the “w” doesn’t directly correlate with weight.
In the case of an engine that uses a mix of oil weights, the 5w20 and 5w30 may show up in different percentages at different times. For example, an owner may take their car to their local mechanic for an oil change and ask for a specific weight. The mechanics will actually weigh the oil and give you a recommendation based on your engine’s needs. If you need anything over 7 quarts (7 liters), you can tell them to use 5w30 instead of 5w20.
Here is the summary:
- What 5W20 and 5W30 have in common is that they have the same viscosity in winter. And, in cold weather, 5W oils flow more quickly.
- The lower “20” number in 5W-20 means that it will remain somewhat thinner at operating temperature, whereas 5W-30 will offer a little thicker lubricating coating.
Why You Should Use 5W20 & 5W30 Oils
Below are some of the benefits of using 5w20 and 5w30 oil:
- Performance: Motor oil increases your engine’s performance. Higher flow allows your engine to flow cooler, which reduces wear on internal engine components.
- Improved Fuel Economy: 5w20 and 5w30 oils are formulated with multiple additives that help improve fuel economy by lowering emissions.
- Smoother Running: Motor oils are used in your engine’s pump, which helps reduce friction.
- Reduced Wear & Tear: Reduce engine wear and tear with motor oil. This improves the efficiency and overall performance of your car.
- Better Protection: Motor oils protect internal engine components from wear and tear by preventing corrosion, offering lubrication for moving parts, and more.
Can You Mix 5W20 and 5W30?
Yes, you can top up your 5W20 with 5W30 or the other way around. Keep in mind that it’s probably not a good idea to mix the two oils, because 5W30 is thicker than 5W20 but the mixture won’t harm the engine anyway.
It’s generally accepted that mixing different weights is better than using one weight for your engine. The reasons are that it’s better for your car to have a wide range of viscosities available. Different viscosities provide different cleaning and lubrication abilities, which is important for keeping your engine clean and problem-free. What’s more, this prevents the thinning effect that happens when using a thin oil for too long.
What Happens if You Mix 5w20 With 5w30?
If you mix 5W20 with 5W30 oil, the result will be an oil with a viscosity somewhere between the two oils. The viscosity of the oil affects how well it flows through the engine and lubricates its components.
As we are all aware that mixing 2 different oils is not recommended, same as these two. Mixing 5w20 and 5w30 motor oil is not recommended because the two motor oils have different viscosities.
This means that they will not be able to mix together to form a single homogenous solution, and the varying viscosities of each oil can lead to uneven lubrication of engine parts.
The lighter 5w20 may flow more quickly than the thicker 5w30 and can cause premature wear in some areas due to inadequate lubrication, as well as sludge buildup in other areas due to excessive lubrication.
So, how does the mixture of 5W20 oil and 5W30 affect the engine? Will we get a result that is a bit of a compromise between the two? Well, it does more harm than good.
Here are a few possible effects of mixing these oils:
- Reduced lubrication: If the mixture of 5W20 and 5W30 oil has a viscosity that’s too low, it may not provide adequate lubrication to the engine’s components, which could result in increased friction and wear.
- Reduced fuel efficiency: If the mixture of oils has a higher viscosity than the recommended oil, it could cause the engine to work harder to circulate the oil, resulting in reduced fuel efficiency.
- Engine damage: Using a mixture of oils that is significantly different from the recommended oil viscosity could potentially cause damage to the engine over time, as it may not provide adequate protection and lubrication to the engine’s components.
What Ratios can I Mix 5w30 with 5w20?
Although mixing the two fluids together may not harm your engine, experts still don’t recommend it as the engine can’t reach its peak performance with mixed oils.
However, in an emergency, if you need to top off an engine with 5W30 oil that is already full of 5W30 oil with 5W20 oil, you should use more of the heavier 5W30 oil and less of the thinner 5W20 oil.
For example, in a 5W30 engine, you might use two parts 5W30 oil and one part 5W20 oil, and vice versa.
You should read the owner’s handbook to make sure you use the correct ratio if your engine allows mixing of both oils.
Is 5W30 Compatible with A 5W20 Engine?
Because 5W30 oil has a greater viscosity and would be too thick for the 5W20 engine’s components, which need a thinner barrier, it might not be a good idea to use it in a 5W20 engine.
As the oil would be too thick to pass through, the engine parts would not receive adequate oil coating, which might lead to overheating, wear and tear, and oil starvation.
Additionally, the engine components would encounter increased resistance as they moved against one another.
When combined with 5W20 oil, 5W30 oil may be secure in 5W20 engines.
What Is Engine Oil 5w20 Good For?
Engine oil 5w20 is an excellent choice for vehicles that are operated in cold climates. This oil is designed to maintain good lubrication at low temperatures, which makes it ideal for winter driving conditions.
It also provides better fuel economy and reduces wear and tear on engine components, making it a great option for those who want to keep their vehicle running smoothly, even in cold weather.
Another plus point is that this type of oil can be used in most modern cars without the need for special modifications or additives. It helps reduce emissions while delivering improved performance and increased engine life.
What Is Engine Oil 5w30 Good For?
Engine oil 5w30 is an essential component of car maintenance and provides numerous benefits to the engine.
Mechanical benefits include:
- Reduce friction between metal parts
- Prevents wear and tear
- Cleans the engine by suspending contaminants in the oil
- Helps to cool down the engine as it circulates through its components
At colder temperatures, 5w30 oil flows more easily than thicker oils so that it can reach all the components of your engine quickly and easily. This means it will provide better protection during cold weather starts when your vehicle has been sitting for a while.
Similarly, at higher temperatures 5w30 is thinner compared to other oils and allows less heat transfer which helps to keep temperatures consistent throughout the entire engine.
The worst thing that can happen to your engine over the summer is that the oil deteriorates; this speeds up wear and could even result in engine knocking. Utilize 5w30 during the summer to prevent this.
Overall, 5w30 oil offers excellent protection for your vehicle’s engine over a wide spectrum of operating conditions from start-up in cold weather to hot summer days spent on long drives.
Are There Any Benefits of Mixing Engine Oils?
Not really. There hasn’t been any scientific proof on this matter. Some people may benefit from mixing oils, but this is only a temporary fix. The long-term effect of mixing engine oils is that this act may lead to faster wear and tear of your engine. Also, changing the amount of base oil in your engine will require a new oil filter and an oil change. So if you’re mixing 5w20 with 5w30, you’ll probably need to change the oil again in just a few thousand miles.
Here are some thoughts on mixing oils from giant oil companies:
Chevron stated on their site that different viscosity grades of the same brand of motor oil might be combined without compromising system performance. However, combining multiple brands is not recommended as it could lead to an inconsistent product with a different overall viscosity than intended.
Shell Canada‘s expert team explains that mixing viscosity grades like a 5W30 low-viscosity oil with a 10W40 higher-viscosity oil can lead to an overall product of thicker consistency than the former but thinner than the latter. Despite this change in thickness properties, their experts assure users there is no danger of any incompatibility arising from combining different engine oils.
At Mobil 1, they always suggest that customers follow their engine manufacturer’s recommendations for selecting a viscosity grade. If you’re ever in doubt about which one to choose, simply refer to your owner’s manual. Additionally, if an individual already has the Tri-Synthetic Series motor oil from them there is no need to mix two different SAE grades – just stick with the same type of formula recommended by your vehicle manufacturer.
Final Thought on Mixing 5w20 & 5w30
To conclude, you can mix 5W20 & 5W30 provided that they’re from the same brand and API. If you want to come up with your own oil mixture, just check the oil number of the two oils. For example, if they’re 5W-30 and 10W-30, then you can use 80% of the amount of the 5W-30 and 20% of 10W-30.
A piece of advice: if you want to prolong your engine’s life, use synthetic oils as they bring various benefits to the motor engine.
Hi, My name is Ollie Barker.
With 25 years working in repair and detailing shops. I’d love to share my tips & tricks to all car lovers. Also, give my recommendations on which products are the best to have on the market.
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