Will 10w30 Hurt a 5w30 Engine?

One of the questions asked most often is, “Will 10w30 hurt a 5w30 engine?” There are lots of misconceptions and myths when it comes to the oil type you should use in your vehicle.

In this article, we’ll cover what the numbers mean and if it really matters.

If you’re like most owners of newer vehicles, then you probably purchased full synthetic motor oil for your vehicle instead of conventional motor oil.

Full synthetic oil is a great choice if you have it available to you because of its unique properties and ability to protect engines in several scenarios including older engines that tend to run hotter than their newer counterparts.

Let’s talk about this specific scenario for a moment: Many newer vehicles are running synthetic blends of 5w30 throughout an engine’s life.

However, older engines that are built with conventional oil technology often require 10w30 or even 15w30 due to the generous amount of seal slop in those engines, in addition to those cars having an overabundance of vacuum leaks.

What is the 5w30 oil?

5w30 oil is a type of motor oil that is suitable for use in many different makes and models of cars. It’s a lighter-weight oil, meaning it flows more easily between the engine’s moving parts than oils with higher viscosity.

The 30 in 5w30 refers to the thickness of the oil when it’s hot (at 212 degrees Fahrenheit). The higher the number, the thicker it is.

The 5 in 5w30 refers to the thickness when the oil is cold (at 40 degrees Fahrenheit). The lower this number, the more easily it can flow through your engine in colder temperatures.

What is the 10w30 oil?

The 10w30 oil is a motor oil used in boats and vehicles. It is a type of lubricant, which means it reduces friction to improve the performance of an engine.

The lubricant is made with an oil base and has additives that help clean the engine and protect it from corrosion.

The number 10 refers to the viscosity of the oil when cold, while the number 30 refers to the viscosity when hot.

The 10w30 oil can be used in both diesel and gasoline engines, as well as in boats. In addition, it can be used for both 4-stroke and 2-stroke engines.

The oil is suitable for use in climates where the temperature tends to be significantly lower during certain months of the year.

What is the difference between a 5w30 and 10w30 oil?

A 5w30 and a 10w30 oil are both oils that provide lubrication to the moving parts of your engine. However, they differ in that a 5w30 oil is thinner at lower temperatures than a 10w30 oil, while at higher temperatures they have the same viscosity.

5w30 and 10w30 oils start out different when they’re cold. The number after the “W” stands for winter, and can be read as “winter weight.” Therefore, a 5w30 oil has a lower viscosity when it’s very cold than a 10w20 does.

This is important because if you live in an area with extremely cold winters, you want an oil that will be able to circulate well even at low temperatures, so it can keep all the moving parts of your engine from grinding against one another.

At higher temperatures, though, they are both nearly identical. This means that while you might use a 5w20 during the winter, you could switch to a 10w20 during the summer if you wanted to.

Can you use 10w30 instead of 5w30 in your car?

In many cases, you can use 10w30 rather than 5w30 for your car, although you should check your owner’s manual first.

The main difference between 10w30 and 5w30 is that the former has a viscosity of 10 at low temperatures and a viscosity of 30 at high temperatures, while the latter has much lower viscosity at low temperatures.

That means that if you live in an area with very cold winters, it’s probably best to stick with the 5w30. If you live in a place with mild winters, however, switching to a 10w30 oil might be fine.

In general, using a more viscous oil will not hurt your car, but it can make your engine run less efficiently.

Will 10w30 Hurt a 5w30 Engine?

No, it will not hurt your engine. The 10w30 oil in your 5w30 engine will just become thinner and flow more freely as the motor heats up.

This is not a problem because high temperatures are precisely when you want your oil to be thin, so it can adequately lubricate the moving parts of your engine.

It is not recommended to use 10w30 motor oil in an engine that requires 5w30. If the temperature drops below freezing, the thicker oil will not flow easily enough and may cause damage to the engine.

In extremely cold conditions, you can use 5w30 motor oil for your engine. In warm weather, motor oil tends to drain from the engine. The 5w30 helps keep it in place even when temperatures are hot, ensuring smooth operation of all parts of the engine.

When to Use 10w30 vs 5w30?


10w30 is appropriate for most cars. It is also the most common motor oil viscosity grade. If you are looking to buy motor oil, you will likely buy 10w30.


5w30 is best for areas with cold weather. It has a lower viscosity that keeps it from getting too thick when the temperature drops. It’s a good option for people who live in an area where their winter temperatures drop below -20 degrees Fahrenheit.

Which oil is thicker 5w30 or 10w30?

5W-30 is thicker than 10W-30. The “W” in both of these designations stands for “winter.” The number tells you how thick the oil is at 0 degrees Fahrenheit. The lower the number, the thicker the oil. So 5W-30 is thicker than 10W-30 at 0 degrees Fahrenheit.

The 5 in 5W-30 simply means that if you were to measure this oil’s viscosity at 212 degrees Fahrenheit, it would act like an SAE 5 motor oil, meaning it would be very thin and flow very easily.


If the owner’s manual recommends a certain motor oil viscosity, then use it. Using 10w30 in a 5w30 engine isn’t going to hurt anything when the alternative is a thinner, 5w20, or 0w30 weight oil.

When it comes to what your engine builder recommends, however, you should defer to them and their experience.

If they designed and built your engine, then they know best what the operable parameters are for the vehicle in question. If you’re unsure about this, ask them why they recommended 10w30 rather than 5w30 or another weight entirely.

About Nurul Islam 157 Articles
I am Md Nurul Islam (Jewel), a Professional SEO expert, and a blogger. I am an automotive enthusiast also I started creating this website because I have always loved cars and bikes.