10w30 Vs 30w: What Are The Differences Between Them?

Engine oil is one of the most essential parts of a vehicle. It can either make or break the machine’s performance.

30W vs 10W30

There are mainly two kinds of oil that you use in the engine. One is monograde and the other is multi-grade. If you aren’t sure which one to choose for your vehicle, then give this article a read.

Here I will explain the traits of two oils using 10W30 Vs 30w as examples.

What Is 10w30 Gear Oil?

10w30 is a multi-grade gear oil that changes its viscosity level as temperature changes. It is rated 30 at higher temp and 10 at lower temp.

The reason for this flexibility is that it comes with a special additive called polymer that changes its traits when temperature rises or falls.

10w30 may not be the thinnest but thinner than most oil with higher viscosity levels. Because the oil has lower rating, it flows faster across the engine parts so that they run smoothly when it’s cold.

That’s why the oil is preferable to be used at lower temp. However, since the oil can be thick, you can also use it at normal to slightly high temperatures.

Advantages Of 10w30 Gear Oil

Offers Incredible Cold-Start Performance

When the temperature drops, the polymers curl up into a tight ball and move freely with the oil molecules to flow quickly. This way, the oil helps make the engine start quickly in winter while delivering lubrication to all the parts.

Protects Engine At Normal To Slightly High Temperature

With the increase in temperature, the polymers of 10w30 oil grow into a big stringy-like structure. It works to maintain thickness at high temperatures so that it keeps the tight parts protected.

Great For Different Vehicles

Due to the flexible nature of oil, you can use it for any vehicle that uses petrol or diesel engine. It’s ideal for passenger cars, trucks or any heavy-loaded vehicles.

Keeps The Engine Parts Clean

10w30 engine oil takes out sludge build up and varnish deposits caused due to oxidation. It mainly features detergent additives that help in keeping the engines clean.

Disadvantages Of 10w30 Gear Oil

Not Suitable For Higher Temperature

Although the oil has viscosity level of 30, it’s not thick enough to provide the engine parts with sufficient protection at higher temp.

May Suffer From Shearing

Since the oil has viscosity index improvers, it can cause polymer shearing under heavy conditions and high stress.

What Is 30w Gear Oil?

30w refers to solid gear oil that has static viscosity rating regardless of the temperature. Since it’s a monograde oil, it’s used over a small temp range.

Oil with a 30w grade viscosity is pretty thick, which makes it ideal for using under higher temp. It features additives that help reduce friction by acting as a sealer among the engine parts.

Advantages Of 30w Gear Oil

No Polymer Shearing Issues

30w engine oil will not suffer from polymer shearing. It’s because the oil doesn’t have any viscosity index improvers in it.

Acts As A Sealer

Usually old engines develop bigger gaps between the cylinder wall and the rings, which reduce the efficiency of the vehicles. In such situation, 30w oil fills the clearance and helps protect the engines for longer period.

Suitable For Small Air-Cooled Engines

30w oil is mainly suitable for gas-powered chainsaws, generators, garden tractors and lawnmowers that use air cooled engines.

Reduce Oil Consumption

The oil helps decrease leakage past the piston rings. As a result, it works to reduce oil consumption so you can use it for longer time.

Disadvantages Of 30w Gear Oil

Not An All-Season Oil

Thick viscosity is never an ideal option to be used under lower temp since it doesn’t flow quickly across the engine. As a result, it causes hard start reducing the performance of the vehicle.  

Not For Modern Engines

Latest engines rely on instant oil pressure that 30w cannot provide. That’s why the oil is used for limited vehicles and machines.

Comparing 30w Vs 10W30

Performance At Varying Temperature

30w is surely not a flexible oil compared to 10w30 oil. Because of its rigid thickness, it may not perform well under lower temp but it’s great for the high temp. When it comes to 10w30, it can work incredibly at lower temp and decent at normal temp. 


10w30 is highly compatible with different diesel and petrol engines so you can use it in a variety of vehicles. Since 30w has static viscosity rating, it goes well with air-cooled engines.

Read also: 10w30 Vs 20w40: Key differences between them.

Bottom Line- Which One Is For You?

The thickness of both 10w30 and 30w oils can be great for using under normal to slightly higher temp.

It’s just that the latter won’t maintain its optimal viscosity at lower temp like 10w30 will. This is what makes the multi-grade oil different from monograde counterpart.

Both have advantages and disadvantages but you would face the latter mostly if you use the oil in the wrong place.

Now as you know the characteristics of 10W30 vs 30w, hopefully, you won’t be making any mistake.

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