SAE 30 vs 10W30 Oil – What’s The Difference?

Last Updated on January 7, 2022 by Grow with Bovees

If you’ve ever wondered what the difference is between SAE30 engine oil and SAE 10W30, and other grades of oil such as SAE 5W30, then you’re in the right place.

It can be very confusing deciding which one to pick at the store when you’re staring at a rack of oils that all have different numbers written on the bottle.

Knowing your oil grades is an important part of running and maintaining motor engines so we’re going to take a look at SAE 30 oil, what it is, where to use it and how it compares to other oils such as an SAE 10W30 grade.

What Does SAE Stand For?

First of all, it’s important to understand what the SAE rating actually means.

SAE is a scale developed by the Society of Automotive Engineers to measure engine oil viscosity and is defined by the SAE J300 standard.

It’s usually written as a numerical code with a standard notation of “(X)XW-XX” or “(X)XWXX” where “X” is always a number.

Understanding Oil Viscosity

All types of motor oil, whether it’s synthetic or conventional, are classified according to their viscosity.

Sounds complicated but really it’s just a term to describe how quickly the oil flows through your motor and oil filter at different operating temperatures.

Thinner oils flow a lot faster than thicker ones and engineers design the advanced engines of today around the use of a certain oil viscosity that provides the best performance.

As modern cars are used in a range of environments, sometimes with a wide range in temperature, engine oil types are needed with sufficient oil flow at a temperature range of extremely cold and very hot, plus everything in between.

Winter SAE Grades

The number (or numbers) before the “W” (which stands for Winter) rates how well the oil flows at zero degrees Fahrenheit (which is -17.8 degrees Celsius). The lower this number is, the thinner the oil is in colder temperatures.  

For example, a 5W30 oil thickens less in cold weather than an SAE 10W30 motor oil.

This is important as cold-cranking an engine in winter will be far easier with a lower W rating.

Warm Temperature SAE Oils

The last set of numbers after the “W” signifies the viscosity of the oil at 100 degrees Celsius (212 degrees F) and tells us how well the oil resists thinning at high engine temperatures. The higher the number the better it is at resisting high operating temperatures.

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For instance, oil with a grade of SAE 10W30 will thin more quickly than 5W-40 motor oil at high temperatures.

Choosing the Right Grade

When comparing motor oils and oil thickness, the location where the car, boat, OPE, etc. will be used is an important factor.

Thicker oils that are less prone to thinning are better for summer temperatures whereas thinner oils that stay viscous at low temperatures will help you to cold-crank your heavy-duty 4 cycle engine vehicle in winter.

As a result, oil companies have developed grades for colder climates such as 0W-20 and 5W-30 while 20W-50 and 30W-50 oil has been developed for use in hotter climates.

What Is SAE 30 Oil?

As you can see, SAE30 oil has no W rating, just a single viscosity grade of 30.

For that reason, it’s known as a single-grade or mono grade oil which is different from a multi grade oil like SAE 10W30 engine oil, which is rated both for SAE30 and SAE 10W.

When an oil is designated as a single grade oil, this could be either hot viscosity or cold-start viscosity, in which case it would have a “W” suffix.

In the J300 standard, there is no W rating for SAE 30 oil so it is only rated for use in warmer temperatures.

Next, let’s see where you’d typically use SAE 30 motor oil.

What Is SAE 30 Oil Used For? 

SAE 30 oil is typically used in 4-cycle small block engine machines such as mowers, small tractors, boats, etc., or industrial applications where the temperature does not vary much.

Also, while most passenger vehicles in use today have modern engines that require multi-grade type oils, you will still find some four-stroke gas engines that require an SAE-30 oil, such as motorcycles and older cars.

Very old 2-stroke engines on chainsaws, leaf blowers, lawn mower engines and other garden equipment may also call for SAE30 oil to be mixed in with the gas for fuel, although most newer models with a typical 2-cycle air-cooled engine will require a specialized 2-stroke oil.

To be safe, always follow the manufacturer’s recommendations to be sure you are using the correct grade to avoid issues.

SAE 30 Oil Compared to Other Grades

The most popular FAQs we get are how SAE 30 oil compares to other single-grade and multi-grade oils, so let’s go through the most popular questions on this topic.

What’s The Difference Between SAE 30 And SAE 40 Oils?

SAE 30 is a thinner oil than SAE 40.

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This means SAE 40 will remain thicker at higher temperatures so it is often recommended for use in a heat-sensitive engine.

If an engine manufacturer recommends the thinner oil be used, there is no advantage to using the thicker oil. Doing so could actually cause damage to your motor, or engine issues.

SAE 30 vs 10W30 – Are they the Same?

The short answer to this is no, 10W-30 oil is not the same as SAE 30.

The difference between 10W30 multi – grade and straight grade oil is that it has been formulated to provide a 10W viscosity at very low temperatures to aid in cold-cranking in heavy engines.

It can be used in place of SAE 30 in compatible engines as it provides the same SAE 30 rating at hotter operating temperatures, but always follow manufacturer guidelines.

Is SAE 30 The Same As SAE 30W?

In the SAE J300 standard, there is no SAE 30W (which is a cold weather grade), only SAE 30.

That means the single grade type oil is only rated at 100 degrees C so should be used in engines and environments where the ambient temperature remains warm and constant to avoid engine issues.

Is SAE 30 a Non-Detergent Single Grade Oil?

Older SAE 30 single-grades were non-detergent mineral-oil-based engine oils used in lighter engines.

Modern oils often contain additives (see below) including detergents, although you can buy additive-free mono grade oils.

If an oil is free of additives it will usually be marked as such on the bottle.

Does SAE 30 Oil Have Additives?

SAE 30 oil, as with many modern engine oils, will usually contain additives to enhance engine protection and improve performance.

Oils also often contain detergents that are designed to trap dirt particles and keep a motor clean in-between oil changes by dissolving motor oil sludge.

However, a single grade oil like SAE 30, cannot use polymeric viscosity index improvers.

Is SAE 30 Synthetic oil?

SAE 30 motor oil can be both synthetic and mineral-based.

Synthetic oil is an oil type, whereas the SAE oil grade just refers to its viscosity.

Can I Use 5W-30 Instead of SAE 30?

Yes, you can use a 5W-30 viscosity grade oil instead of SAE 30.

Both oils have a hot viscosity rating of 30 so the multi – grade function will behave the same way at a  warmer operating temperature as the single grade function.

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The same goes when comparing SAE 30 vs 10W30 oil.

Can I Use SAE 30 as Lawn Mower Engine Oil?

SAE 30 is often recommended as lawnmower motor oil and other applications with a light small block engine.

Always check the owner’s manual first to make sure you don’t need to use a double grade oil.

Can I Mix SAE 30 Oil With 10W-30 Oil?

SAE 30 and 10W30 can be mixed together as the J300 standard requires all SAE engine oils to be compatible with each other.

However, by creating a mono grade multi-grade mix you will be changing the viscosity into something unknown which is not recommended.

Remember, when comparing SAE 30 vs 10W30, the multigrade oil can be used in place of the single grade and will in fact work better at both cold temperatures and warm temperatures.

Can I Use SAE 30 Oil In Diesel Engines?

In some older diesel engines, SAE 30 motor oil may be recommended by the manufacturer.

Before using the SAE 30 oil, check the manual to see which Diesel Engine industry classification is needed e.g. API CJ-4 or API CF-4, and make sure the oil meets those specifications. This will be listed on the bottle.

Note: API (American Petroleum Institute) “S” classifications like API SN and SJ are for gasoline engines, not diesel engines.

Final Thoughts

Motor oil lubricants such as SAE 30 oil are essential in keeping the internal engine components on your car, lawnmower, snowblower, etc. running smoothly.

As a result, using the right oil grade for your motor is very important, whether it’s for modern four-stroke engines or just to keep your standard 2 cycle air-cooled engine on your chainsaw in good shape.

The last thing you want is to damage the engine unnecessarily by not following the manufacturer’s guide so always check your manual or official website to find out what recommended engine oil you need to use.

If you can use either single or multi-grade, when choosing between SAE 30 vs 10W30 oil, the multigrade will work better at lower temperatures and is great for small engine vehicles.

It’s also important to check the oil level regularly to keep a check on oil consumption. Modern machines have indicators like a low fuel warning light and oil warning light that will alert you if something needs checking.


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