75w85 Vs. 75w90 Motor Oil: The Head-to-Head Comparison

Automobiles are evolving day by day for our daily convenience. Along with this exponential improvement, automobile accessories are also improving. 

One of them is gear oils. 

Gear oils are being more compatible for use. But, there’re some regulation factors you should take into consideration before buying the right gear oil. And talking of gear oils, 75w85 and 75w90 are the top choices among vehicle owners.

Now, the difference between 75w85 and 75w90 isn’t that distinguishable. Both of these oils are high-grade lubricants with many efficient features. 

Anyway, we’ll be taking you through an in-detailed comparison of 75w85 vs. 75w90. Jump on the train!  

Can I Use 75W85 Instead of 75W90?

Yes, you can use 75W85 instead of 75W90. Changing gear oils don’t make that big change unless there is a significant change in the viscosity property.

But, before changing your gear oil, make sure if the alternative lubricant is compatible with your automobile.

You can distinguish the Difference between your gear oils and quickly get them through on-site tests. For example, both of them have viscosity differences, which you can check by yourself. 

In short, you can use 75w85 instead of 75w90. But 75w90 gives a bit better performance than 75w85. The change is not so significant to notice. 

But, yes, through tests, you can see that 75w90 is a bit decent. 

What Happens If You Use 75w85 Instead of 75w90?

Nothing significant happens if you use 75w85 instead of 75w90. But you can completely go from one grade of lubricant oil to the other grade because there are differences in chemicals, additives, and viscosity. 

Viscosity change on a small scale isn’t a big problem. But on a more considerable scale, viscosity changes can cause your gear to clog. 

And also, there’s a noticeable change in the additives.

To sum up, 75w85 and 75w90 don’t have significant differences. You can interchange the oils. Nothing will happen. But, make sure the additives of both the oils don’t react. And get both the oils from the same vendor. 

Comparison Chart

Here is a quick sneak peek of the differences between 75w85 and 75w90 for your convenience. 

Viscosity Moderate level viscosityMore viscosity than 75w85
AdditivesMostly boron and chlorineMostly boron, chlorine, and phosphorus
Shear StabilityMedium viscosity resistanceHigh viscosity resistance
Weather compatibilityModerately maintains texture during low temperatureCan maintain texture in both high and low temperature
Gear ProtectionCan protect from rust and foamIt can also protect from rust and foam
Oil FormMedium concentration and thicknessHigh concentration and thickness

What is the Difference Between 75w80 and 75w90 Oil?: In-Depth Comparison

Every lubricant gear regulates on some general factors. These attributes maintain the shape of those oils and differentiate them. We gave some of the main primary factors.

1. Kinematic Viscosity

Kinematic viscosity is necessary for grading a gear oil for winter use. During winter, the gear gets clogged, which may be a significant problem and cause the engine to stop functioning. 

So, when lubricants are applied, it decreases the friction, which contains the gears from functioning, thus giving the gears a bit more flexibility.

Gear oils are graded by the time it takes to flow through a standard surface at an average temperature. The longer duration it takes, the higher the viscosity index. Density affects the movements of the gears in the engines or external parts. Plus, it depends on the temperature as well. 

We know the more the grading, the more the viscosity. So, you can grade the thickness of 75w85 as 85. Which is moderate level thicker, which means consistency is more. 

75w90 is thicker than 75w85. It’s a winter-grade lubricant oil. For winter-grade lubricant, oil thickness is necessary. So, with increased thickness, viscosity also increases.

2. Additives

Additives come after viscosity marking or grading. We all know that viscosity is the most critical factor in the case of lubricant oils. But other than viscosity, there’re some more factors for a lubricant. One of them is additives. 

The additives of lubricants can be organic or inorganic. They’re mostly suspended or dissolved in lubricant oils. Additives mainly control the physical properties of the lubricant oils. 

For instance, foaming is a big problem for gear oils. Additives make gear oils more resistant to foams.

75w85 has anti-rust additives. That gives it a unique ability to prevent rust from forming in the gears. And also, the additives used in 75w85 are pretty good at pressure handling. 

Better additives mean better traction. You can quickly start your engines in the winter seasons if the lubricant additives are of a good grade. In this case, 75w90 is the best option because its viscosity changes proportionally with the temperature due to additives.

3. Shear Stability

Viscosity can change if any sorts of external properties are applied. For example, we told you that density is inversely proportional to temperature. So, if the temperature increases, viscosity decreases. 

In addition, viscosity gives movement to the gears in the engines. It’s essential for the tear and wears rate of the performance. The property of resisting those shear abilities is known as shear stability. 

Shear stability can change the thickness of your lubricant. And according to that thickness, you can choose the oil for your engine, which will increase of traction of your machine. 

It should be considered while buying any lubricant oil. Shear strength is also dependent on additives. The more the additives, the more the viscosity. And the more viscosity, the more the shear resistance.

75w85 has moderate level thickness. So, the shear stability of 75w85 is relatively more minor. But by adding external additives, the thickness can be increased along with its shear stability. 

Shear stability of 75w90 is quite good. 75w90 is a lot thicker than 75w85. Because of additives. For which its shear stability is also good. 

4. Collaborative Attributes

You can mix 75w90 with any other oils and won’t have a problem. It will give the same performance before and after mixing the oils. Moreover, if the collaboration between the oils is done correctly, it may provide better performance.

For this situation, your best option is 75w85. You can mix it with any oils, and it will still be convenient for use. &5w 85 is widely used for doping for increased performance. So, we are sure there won’t be any problem.

5. Boundaries of These oils

Oils can lose their normal flexibility if the weather gets too critical, i.e., the temperature gets up the crucial point. 

When the temperature rises too much, the oils get too thin the movement increases. Increasing movement means it gets into a liquid state, makes a great mess, and can damage your engine.

These are winter-based oils that can maintain their properties at low temperatures. So, hot tropical areas are not that much compatible with these oils. Consider taking other grade seasonal lubricants for warm environments.

6. Weather compatibility

The Winter season is a general problem for lubricant oils. Oils get thicker due to decreasing temperature. Which means their locomotion and viscosity get limited. Low viscosity means low friction, which can clog the engine gears.

75w90 graded oils are specially made to preserve their properties even in cold weather. And also, it has a great feature to adapt to constant changes in the temperature.

On the contrary, 75w85 also has similar features. It gets concentrated in a warm environment and thin in the winter season. This feature will give you more flexibility in the winter season.

7. Safety features

We all know that rust gradually corrodes metal. And also, it can happen if the parts come in contact with moisture. 

But, here is a piece of good news. 

75w90 can resist water vapors and protects the gears from corroding and rust formation. All these happen due to the inclusion of additives in the OilOil, which gives them hydrophobic properties.

On the other side is 75w85 is isolated. It can only function as a lubricant and can’t give that much safety. But, remember you can mix both of these oils and increase their performance.

75w80 or 75w90: The Final Bargain

We’ve discussed the regulation factors of lubricants above. Oils are crucial for gears, and gears need to move freely. Also, lubricants have some specific properties. For instance, oils change their properties according to temperature. 

Other than that, many factors affect the physical properties of the lubricants. One of them is additives. Make sure the additives are organic because organic additive lubricants give optimum performance.

Both of the lubricants are good. But they’ve some specific differences. 75w90 is a bit thicker than 75w85, which means its viscosity is also higher. 

Both oils are highly beneficial for winter use. They’re massively used in winter-based areas. 

But let’s get back to the main stuff. 75w90 is a bit better than 75w85. We gave that decision because 75w90 has better additives than 75w85 which provides it with a great go.


Can You Swap 75w90 With 75w85?

Yes, you can use 75w85 instead of 75w90 or vice versa. Oils can be interchanged and can be replaced without any harm.

 What Does W-Grade Functionality Mean In Lubricant Oils?

The W in of the gear oil means winter. Which means it’s a winter-compatible oil. You can use it in winter, with no visible problems.

Does Shear Stability Matter For Choosing Gear Oil?

 Shear stability is the resistance of viscosity. So, shear stability is necessary for choosing gear oil. 

 Do Additives React Between Two Oils?

Yes, additives can react sometimes. The reaction happens if the gear oils are of different grades. 


We hope you got an excellent 75w85 vs. 75w90 comparison. Both of the oils are pretty efficient. And also, they can work collaboratively. These lubricants are best for winter as they don’t get your gears clogged due to temperature drops. 

Among these two lubricants, 75w90 is a little more efficient. But the change is not that quite distinguishable.

Hopefully, by now, you’ve decided which one to choose. If you did, well, we wish you the best of luck.

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