There are a lot of myths surrounding motor oil. Some people believe you can mix different types of oil together and that it will hurt your car if you’re not careful.
The truth is, mixing two different types of motor oil can damage your engine if you’re not careful. This is why it’s very important to be well-informed before trying it out.
So, should you use 10w30 or 5w30 separately in your car? Or both?
Read on as we break down the difference between these two types of motor oil, whether or not you should mix them together, and if so, the safest way to do that.

Table of contents
Can You Mix 5w 30 and 10w 30?
Yes, you can mix them. They’re both very similar in viscosity and can be used interchangeably without negatively impacting your car’s performance. However, there is one thing you should pay attention to additives.
Does Mixing Different Types of Motor Oil Damage Your Engine?
No, mixing different types of motor oil does not damage your engine. There’s no reason to worry about mixing different types of motor oil.
Mixing 5W30 and 10W30 will not damage your engine. Even if you use the same brand name, the viscosity of one type of oil (say, 10W30) is usually different from another type (5W30).
This means that it will take longer for each drop of lubricant to pass through an engine’s components and get absorbed into them—but this difference in time will be so slight that you won’t even notice it when driving or changing your car’s motor oil.
It won’t affect your engine’s performance either; while some people may claim otherwise, there are no scientific studies confirming their claims.
Should You Put 10w30 Oil in Your Car if the Manual Says 5w30?
You can use 10w30 in a 5w30 car. The labels on the oil are guidelines—they’re not written in stone. The numbers refer to how thick the oil is, which means how well it will flow at certain temperatures.
Generally, a lighter-weight oil flows easier at cold temperatures and becomes thicker as it heats up, whereas a heavier-weight oil stays relatively thin even when hot.
So, if you live where it’s cold and icy half of the year, then you may want to use something like 5w30 because it has less viscosity than some other oils that would get stuck in your engine during those frigid months.
On the other hand, if you live somewhere that’s hot for most of the year, then 10w30 would be better because its higher viscosity means less heat gets lost through leaks in your engine block when things get really hot outside.
What is the Difference Between 5w30 and 10w30 Engine Oil?
When it comes to choosing the right motor oil, you may have heard that there are two basic types: 5w30 and 10w30. But what exactly does this mean?
The first number in a motor oil’s designation tells you how thin or thick it is. Thinner motor oil will flow more easily at cold temperatures.
Thicker motor oil will stay in place better at high temperatures and during high loads on your engine, like during hard acceleration or heavy loading (like hauling lots of people or cargo).
In other words, if you live somewhere with colder winters, then a 5w30 would be the better option since it flows more easily when things get chilly outside.
If you live somewhere where things are hotter than average but not too hot, then maybe a 10w30 would suit your needs better because it sticks around long after being exposed to heat instead of draining away into oblivion as soon as summer rolls around every year. You can check out this post to get a clear understanding of the 10w30 oil vs 5w30 debate.
How to Mix 10w30 and 5w30
If you’re going to mix your own oil, the first step is to get yourself some 5W30 and 10W30. You’ll need about one quart of each. It’s best if these are in dark bottles so you can easily tell when they’re low on oil.
There are two ways that people tend to mix their own oil – by adding the lightweight first and then topping off with the heavyweight, or by adding all of the oil at once and then letting it run for a few minutes before checking the level with a dipstick or other measuring device.
If you choose the latter, make sure not to fill above the full mark on the dipstick (or whatever else you use).
If you want a more precise measurement than simply “full” or “almost empty,” here’s what we suggest – add half as much 5W30 as is required in your vehicle’s owner manual (the manual will state how much total volume must be added), then add another half as much 10W30 required–and then, top up with more 5W30 if needed.
FAQs on 10w30 and 5w30 Oil
When Should I Use 10w30 Oil?
You should use 10w30 oil mostly during summer in heavy-load vehicles and hot temperature settings. They make your car go smoothly in summer conditions compared to using other types of oil.
Is 30W the Same as 10w30?
The answer is no, 30w. is not the same as 10w30. 30 wt oil is a single viscosity while 10w30 is multi-viscosity.
Single viscosity means that the oil has one thickness or consistency throughout the entire bottle. Multi-viscosity means the oil has different thicknesses depending on where you are in the bottle.
This helps to provide cooler running temperatures as well as better lubrication at higher operating temperatures and helps increase its lifespan as well.
Is 10w30 Ok for Winter?
Yes, 10w30 is okay for winter as long as the temperature is not freezing else this might become a problem. The temperature should not exceed -30°C/-22°F in the winter.
Can 10w30 Be Used as Hydraulic Oil?
Yes, 10w30 can be used as hydraulic oil but it’s important to use the right viscosity for your needs and also the type of devices you are using it with.
A 10w30 motor oil, for example, is too thin and will cause excessive wear in a hydraulic pump designed to operate with a 210 SUS fluid that has a viscosity of at least 6.8 cST at 100°C.
Can 10w30 Be Used in a Diesel Engine?
Yes, 10w30 oil can be used in a diesel engine. The 10w30 designation is actually the viscosity of the oil, or how thin or thick it is. The higher the number, the thicker it is.
Since diesel engines run hotter than gasoline engines, they need thicker oils to keep friction down and allow a better flow of oil through their systems. So yes, 10w30 can be used in a diesel engine.
Are All 10w30 Oil the Same?
All 10W30 oil are not the same. If you’ve ever had the misfortune of having to replace your car’s engine, you know that the type of oil recommended by a mechanic can be pretty important to whether your engine stays healthy.
Not only does it need to be 10W-30 weight, but it also needs to have certain additives in order to cover all of your vehicle’s moving parts.
Can I Use Sae 30 Instead of 5w30?
No, you cannot use Sae 30 instead of 5w30. This is because sae30 is a single-grade viscosity oil, unlike 5w30.
Which Is Thicker Between 5w30 and 10w30?
The 10w30 is thicker than the 5w30. However, they both have their different benefits for the car’s engine.
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Conclusion
In conclusion, yes, you can mix 10w30 and 5w30 oil. You should not be worried that doing so will harm your car or engine. In fact, it’s quite the opposite. Since you have two different kinds of oil available to use, mixing them together means that you can save money by buying one type of oil instead of two separate ones.

Ugo is a passionate car enthusiast with a Bachelor of Electrical and Electronics Engineering degree and hands-on experience in troubleshooting and fixing automobiles.
I combine my electrical and mechanical engineering knowledge with practical skills to address car-related issues.
My love for cars and dedication to educating others led to the creation of Fixandtroubleshoot.com!