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Hydraulic Oil 32 vs 46: 7 Key Differences

Hydraulic oil is a crucial component in operating various industrial and mobile equipment, from forklifts and excavators to power steering systems in vehicles.

Two of the commonly used hydraulic oils are ISO 32 and ISO 46. While they share some similarities, there are significant differences that have to be considered.

One difference between hydraulic oil 32 and 46 is the specific applications that each oil is suitable for. For instance, ISO 32 is mostly used in agricultural machinery, forklifts, construction equipment, automotive lifts, and marine equipment.

In contrast, ISO 46 is used in heavier machinery like machining headstocks, power steering systems, heavy construction equipment, and industrial compressors.

We’ll discuss the differences between hydraulic oil 32 and 46 so you can make the right decision for your vehicle and machinery.

Hydraulic Oil 32 vs 46: 7 Differences to Consider

Hydraulic Oil 32 vs 46: 7 Differences to Consider

In the case of hydraulic oils, the choice between ISO 32 and ISO 46 can significantly impact the performance and longevity of your equipment. Here are 7 key differences when comparing hydraulic oil 32 and 46.

  • Specific applications
  • Density
  • Kinematic viscosity
  • Temperature and climate considerations
  • Flash point
  • Pour point
  • Cost

1. Specific Applications

Hydraulic oil ISO 32 is commonly used in agricultural machinery, such as tractors and combines, to ensure smooth operation and protect against wear and tear.

Forklifts in the material handling industry also rely on ISO 32 hydraulic oil to power their hydraulic systems, facilitating the lifting and lowering of loads. In the construction sector, excavators, diggers, and loaders often use ISO 32 hydraulic oil to maintain the efficiency of their hydraulic systems.

Automotive lifts in car repair shops and garages also utilize ISO 32 hydraulic oil for proper and safe functioning. Additionally, ISO 32 hydraulic oil is employed in marine equipment, such as winches and cranes on ships.

Conversely, ISO 46 hydraulic oil, with its slightly higher viscosity, finds applications in machining headstocks for adequate lubrication and sealing properties.

It’s also used in power steering systems of vehicles, especially larger ones, to improve lubrication and performance. Heavy construction machinery like bulldozers and large compressors may benefit from ISO 46 hydraulic oil due to its thicker nature, which enhances sealing and lubrication.

Furthermore, ISO 46 hydraulic oil can be found in various industrial compressors, where its properties contribute to overall efficiency and durability.

2. Density

To understand the distinction between Hydraulic Oil 32 and 46, it’s important to consider their respective densities.

The density of Hydraulic Oil 32 is 0.868 *10³ kg/m³ or 54.2 lb/ft³ at 60°F (15.6°C). Conversely, Hydraulic Oil 46 has a density of 0.869 Kg/L.

Density measures how much mass is packed into a given volume. It plays a crucial role in determining the performance and suitability of hydraulic oils in different applications.

The difference in density between Hydraulic Oil 32 and 46 may affect their ability to flow, lubricate, and transfer power in hydraulic systems.

3. Kinematic Viscosity

Kinematic viscosity is a measure of a fluid’s resistance to flow. ISO 32 hydraulic oil has a kinematic viscosity of 32.2 cSt at 104°F (40°C) and 5.52 cSt at 212°F (100°C).

Meanwhile, ISO 46 hydraulic oil has a higher kinematic viscosity, with values of 46 cSt at 40°C and 7.0 cSt at 100°C.

The difference in kinematic viscosity between these two oils is significant. The higher kinematic viscosity of ISO 46 oil means that it’s thicker and offers more resistance to flow compared to ISO 32 oil.

4. Temperature and Climate Considerations

Hydraulic Oil ISO 32 is ideal for cold temperatures due to its lower viscosity, allowing it to flow easily even in chilly conditions. This makes it a reliable choice for equipment like agricultural machinery and forklifts that operate in colder climates.

In contrast, Hydraulic Oil ISO 46 is better suited for moderate to warmer temperatures. Its higher viscosity ensures slower flow, which is beneficial in environments with elevated temperatures, such as industrial compressors and power steering systems.

5. Flash Point

The flash point of Hydraulic Oil ISO 32 is 212°C (414°F), whereas ISO 46 hydraulic oil has a higher flash point of 230°C.

Flashpoint is the lowest temperature at which a substance can vaporize to form an ignitable mixture in air. A higher flash point indicates that the oil is less likely to ignite when exposed to high temperatures or sparks.

This makes ISO 46 hydraulic oil more suitable for applications where there’s a higher risk of heat generation, such as heavy-duty industrial machinery or systems operating under extreme conditions.

6. Pour Point

You can further clarify the differences between Hydraulic Oil 32 and 46 by examining their pour points. The pour point refers to the lowest temperature at which a fluid can flow under specific conditions.

In the case of Hydraulic Oil ISO 32, its pour point is -33°C (-27°F). This means that at temperatures below -33°C, the oil will become too viscous and may not flow efficiently.

On the other hand, ISO 46 hydraulic oil has a pour point of -13°C. This indicates that it can withstand lower temperatures before becoming too thick to flow properly.

Therefore, compared to Hydraulic Oil 32, Hydraulic Oil 46 has a slightly higher tolerance for colder temperatures.

7. Cost

ISO 32 and ISO 46 hydraulic oils differ in cost, with ISO 32 generally priced slightly higher than ISO 46.

Hydraulic oil in ISO 32 typically begins at $21.36 for a 1-gallon container but reaches a high of $292.27 for a 5-gallon container. The most common prices for ISO 32 in smaller quantities range from $24.96 to $59.00 per gallon.

Conversely, ISO 46 hydraulic oil has a broader cost range, starting at around $17.61 and going up to $256.86 per gallon. The cost of ISO 46 can vary significantly based on the brand and specific product.

Comparison Chart Between Hydraulic Oil 32 and 46

CharacteristicsHydraulic Oil ISO 32Hydraulic Oil ISO 46
Specific ApplicationsAgricultural, forklifts, construction equipment, automotive lifts, marine equipmentMachining headstocks, power steering systems, heavy construction machinery, industrial compressors
Density0.868 *10³ kg/m³ or 54.2 lb/ft³ at 60°F (15.6°C)0.869 Kg/L
Kinematic Viscosity32.2 cSt at 104°F (40°C), 5.52 cSt at 212°F (100°C)46 cSt at 40°C, 7.0 cSt at 100°C
Viscosity Index (VI)108108
Temperature SuitabilityColder temperaturesModerate to warmer temperatures
Flash Point212°C (414°F)230°C
Pour Point-33°C (-27°F)-13°C
CostSlightly higher price range, from $21.36 to $292.27Broader cost range, from $17.61 to $256.86
Mixing SafetyNot safe to combine due to different viscosity indexes and additivesNot recommended to mix, can lead to potential damage and reduced performance

Is it safe to combine hydraulic oil 32 and 46?

Is it safe to combine hydraulic oil 32 and 46

Combining hydraulic oil 32 and 46 could potentially compromise the safety and performance of your hydraulic system. Mixing these two grades isn’t recommended due to their different viscosity indexes and additives packages.

Hydraulic oils with varying viscosities and additives shouldn’t be mixed as they can lead to potential damage to the hydraulic system and reduced performance.

The different viscosities of hydraulic oil 32 and 46 can affect the lubrication and flow characteristics of the system, causing excessive wear and inadequate lubrication.

Additionally, the additives in each oil grade are specifically formulated to meet the requirements of different hydraulic systems. Mixing these additives can result in chemical reactions, leading to the formation of harmful deposits and decreased oil performance.

What is the recommended frequency for changing or replacing hydraulic oil 32 and 46?

To maintain optimal performance, it’s recommended to regularly change or replace hydraulic oil 32 and 46 in your vehicle or equipment based on the operating conditions and temperature range.

For equipment operating in ambient temperatures ranging from 0 to 90°F (-17 to 32°C), it’s advised to change the hydraulic oil every 1000 hours of operation or annually, whichever comes first.

If your equipment operates in higher temperatures of 90°F (32°C) and above, the recommended frequency is to change the oil every 500 hours of operation or every six months, whichever occurs first.

Make the Right Choice Between Hydraulic Oil 32 and 46 for Optimal Performance

It’s crucial to understand the distinctions between hydraulic oil 32 and 46. These variations in viscosity, application suitability, and performance characteristics can significantly impact the efficiency and longevity of your hydraulic systems.

Whether you’re operating in colder or warmer climates, selecting the right hydraulic oil grade is essential for optimal results. Mixing hydraulic oil 32 and 46 is not recommended due to their distinct properties, as it can lead to reduced performance and potential damage.

In the case of changing or replacing the oil, following the recommended frequencies based on temperature conditions is vital for maintaining the reliability of your equipment. Choose wisely to ensure your vehicle and machinery operate at its best.


Hey, I'm Salinas, an automotive enthusiast with a deep love for the symphony of engines and the thrill of the open road. My passion for vehicles extends beyond the surface; I specialize in automotive oils, considering them the artist's palette for performance. From tinkering with engines to embracing the latest in automotive technology, I find solace in the ever-evolving world of cars. In this fast-paced realm, I'm on a perpetual quest for innovation and automotive excellence. Check out our about for more info.

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