Hydraulic systems play a big role in many types of machines — from industrial equipment to car brakes. The most important part of these systems is the hydraulic medium, which can be either hydraulic fluid or hydraulic oil.
People often use these two terms as if they mean the same thing, but there are key differences that affect how a system works, how long it lasts, and how much maintenance it needs. At Fubex Lubricants, we offer high-quality hydraulic oil for all types of engines. Enjoy fast shipping, a price match guarantee, and no-questions-asked returns. Need help choosing the right oil? Call us at +971 50 544 9614 — our friendly team is ready to assist!
Awais I., Sales Director, says, At Fubex Lubricants, our hydraulic oils are made with advanced additives to deliver smooth operation, strong wear protection, and long equipment life — perfect for machines that need reliable and efficient performance every day.
In this blog, we’ll explain the difference between hydraulic fluid and hydraulic oil so you can choose the right one for your machine and keep it running smoothly.
What is Hydraulic Fluid?
Hydraulic fluid is a special liquid that helps move power inside machines. It’s used in things like hydraulic brakes, excavators, and garbage trucks. The main job of hydraulic fluid is to transfer energy, but it also helps seal parts, lubricate moving pieces, and clean out dirt or contaminants inside the system.
When choosing the right hydraulic fluid, it’s important to look at its viscosity—that means how thick or thin the fluid is. The fluid should stay at the right thickness, even at high temperatures, so the machine keeps running smoothly. Also, hydraulic fluids can sometimes make foam, which can lower performance. That’s why it’s important to use a fluid that removes foam quickly.
What is Hydraulic Oil?
Hydraulic oil is a flammable liquid used to move energy in hydraulic systems. Because it can catch fire, it’s not safe to use in places where high pressure or heat could cause it to ignite. That’s why hydraulic fluid was later created — it works the same way but is safer and less flammable.
Hydraulic oil is made from base oil and special additives. It helps transfer energy, cool the system, and lubricate moving parts. It also helps prevent rust and corrosion, keeping the machine working well even in different temperatures.
What Are the Common Types of Hydraulic Oil?
There are three main types of hydraulic oil:
- General Hydraulic Oil – This type is good for everyday machines. It helps reduce friction and doesn’t break down easily when exposed to air.
- Wear-Resistant Hydraulic Oil – This oil is made for machines that work under high pressure or high heat. It helps protect parts from wearing out.
- Flame-Retardant Hydraulic Oil – This one is used in machines where there’s a risk of fire. It’s designed to resist burning and keep the equipment safe.
What Are the Properties of Hydraulic Oil?
The properties of hydraulic oil are very important because they help machines work smoothly and safely. Here are the main things that make a good hydraulic oil:
- It should be non-compressible, meaning it can’t be squeezed, so it transfers power easily.
- It must stay stable at different temperatures and keep the right viscosity (thickness), even when it gets hot or cold.
- It should be fire-resistant to help keep machines safe.
- It must be non-corrosive, so it doesn’t damage or react with machine parts.
- It should offer anti-wear protection to prevent parts from wearing out.
- It needs to have low foaming and good water resistance, so it won’t get damaged by air or water.
Good hydraulic oils also last a long time and are cost-effective, helping companies save money while keeping their machines in great shape.
Not all oils have every one of these qualities, but there are many types available, so users can choose the one that fits their needs best.
Also Read: Where the Hydraulic Oil Used In Gate Barriers
What Is Hydraulic Fluid?
Hydraulic fluid is a liquid that helps move power inside a hydraulic system. It’s not just one kind of oil — it can also be water-based or synthetic (man-made). These fluids are made to flow smoothly and handle the pressure that machines need to work properly.
Types of Hydraulic Fluids:
- Petroleum-Based Fluids: These are the most common and come from refined crude oil.
- Water-Based Fluids: These include water-glycol mixes or water-oil blends, often used where fire safety is very important.
- Synthetic Fluids: These are man-made and give great performance in extreme heat, cold, or pressure. Examples include esters and silicones.
The Main Differences Between Hydraulic Fluid and Hydraulic Oil
People often mix up hydraulic fluid and hydraulic oil, but they’re not exactly the same. All hydraulic oil is a type of hydraulic fluid, but not all hydraulic fluids are oils.
Think of hydraulic fluid as a big group that includes many kinds of liquids used in machines. Hydraulic oil is just one type of that group.
A long time ago, people even used water as a hydraulic fluid — in Ancient Egypt, it helped move water for farming! Today, hydraulic fluids can be made from salt solutions, water-oil mixes, or petroleum-based oils.
Hydraulic oil is made mostly from petroleum, while hydraulic fluid can include water, mineral oil, or synthetic materials.
The biggest difference is flammability. Hydraulic oils can catch fire when they get too hot or are under high pressure. In contrast, hydraulic fluids with little or no oil are much safer because they don’t burn easily and can work well under many temperatures and pressures.
Uses of Hydraulic Fluid
Hydraulic fluids are made by many brands, like Mobil and Fuchs, and they usually fall into three main types: water-based, petroleum-based, and synthetic-based fluids.
- Water-Based Fluids: These are not very common today. They are used mostly in places where there’s a high risk of fire because they don’t burn easily. However, they don’t lubricate machine parts as well as other types.
- Petroleum-Based Fluids: These are the most popular types. They offer great lubrication, protect parts from rust and corrosion, and keep the system stable even when it’s working hard.
Synthetic Hydraulic Fluids
Synthetic hydraulic fluids are made from man-made materials and give machines extra protection and performance. They provide strong lubrication, keep the fluid stable, and help remove heat from the system. They also protect parts from rust, stop dirt build-up, and can work under high pressure and very hot or cold temperatures.
However, synthetic fluids are usually more expensive than oil- or water-based ones. Also, they might not work well with regular sealants, so it’s important to check compatibility before using them.
In short, hydraulic oil is just one kind of hydraulic fluid. But hydraulic fluids are more flexible—they’re also used in automatic transmissions and are safer to use in places where fire risk is a concern.
Choosing the Right Hydraulic Medium
Picking between hydraulic fluid and hydraulic oil depends on what your machine needs and where it’s used. Here are some things to think about:
- Operating Conditions: If your machine works in very hot, high-pressure, or fire-risk areas, you may need a special hydraulic fluid that can handle those conditions safely.
- Environmental Concerns: In places that need to protect nature, it’s better to use biodegradable hydraulic fluids that are safe for the environment.
- System Requirements: Always check the manufacturer’s recommendations to know which fluid works best for your equipment.
- Cost and Availability: Hydraulic oil is usually cheaper, but special fluids can protect your system better and last longer, saving money over time.
Key Differences Between Hydraulic Fluid and Hydraulic Oil
Composition:
- Hydraulic Fluid: Can be made from petroleum, water, or synthetic materials.
- Hydraulic Oil: Made only from petroleum.
Applications:
- Hydraulic Fluid: Used in places that need fire resistance, environmental safety, or that face very hot or cold temperatures.
- Hydraulic Oil: Common in industrial machines, cars, and heavy equipment because it’s strong and affordable.
Performance:
- Hydraulic Fluid: Can be made to handle special conditions, like fire safety or freezing weather.
- Hydraulic Oil: Gives great lubrication and protects parts from wear and tear in high-pressure systems.
Environmental Impact:
- Hydraulic Fluid: Biodegradable types are safer for the environment and reduce harm if leaks happen.
- Hydraulic Oil: Usually not biodegradable and can be harmful to nature if not handled properly.
Why the Confusion?
People often use the term “hydraulic oil”, but it’s actually just one type of hydraulic fluid. Not all hydraulic fluids are made from oil — some are water-based or synthetic. Knowing the difference helps you choose the right fluid for your machine. The right choice keeps your system running smoothly and makes your equipment last longer.
Don’t settle for less! Check out our range of industrial lubricants to find the perfect match for your needs. Get better performance, save energy, and extend the life of your equipment.
Final Takeways
Knowing the difference between hydraulic fluid and hydraulic oil is important to keep your machines working efficiently and lasting longer.
Hydraulic oil is the most common choice because it gives great performance and is affordable. However, special hydraulic fluids are better for certain uses — like when you need fire resistance or eco-friendly options.
When choosing the right one, always think about the working conditions, environmental impact, and manufacturer’s advice. Picking the right hydraulic medium helps your system run smoothly and stay reliable for years.
Contact us to learn more about the difference between hydraulic fluid and hydraulic oil.
FAQs
Q1: What is the difference between hydraulic fluid and hydraulic oil?
Hydraulic fluid is a general term for any liquid used in a hydraulic system — this includes oil-based, water-based, and synthetic fluids. Hydraulic oil is one specific type of hydraulic fluid made from oil and is popular because it offers great lubrication and stable performance.
Q2: Can water-based hydraulic fluids be used instead of hydraulic oil?
Yes, water-based hydraulic fluids can be used when fire resistance is important. However, most machines use hydraulic oil because it provides better lubrication and can handle higher temperatures. Water-based fluids are usually found in steel mills, mining sites, or other high-heat environments.
Q3: What are the advantages of using hydraulic oil over other types of hydraulic fluid?
Hydraulic oil gives excellent lubrication, reduces friction, and helps prevent wear and tear on parts. It also stays stable at high temperatures and resists oxidation, making it long-lasting and efficient for most hydraulic systems.
Q4: Are hydraulic oil and hydraulic fluid interchangeable?
Not exactly. While hydraulic oil is a kind of hydraulic fluid, they can’t always replace each other. Hydraulic fluid includes many types — like water-based or synthetic fluids — made for different uses. Hydraulic oil is preferred for its high performance and wide range of applications.
Editor-at-Large
A passionate writer in the lubricant industry, Awais Iqbal has been covering oils, greases, and industrial fluids since the start of his career. At 25, he’s already written for blogs, catalogs, and brand guides across the UAE. Awais’s insights help companies connect with their audience, and his clear, helpful writing style is trusted by brands in the region.
