When it comes to industrial, agricultural, or construction machinery, choosing the right hydraulic oil is key to ensuring that equipment works well and lasts longer.
In Puerto Rico, where temperatures are high most of the year, oil viscosity plays an important role. That’s why many people ask themselves: what is the difference between 46 and 68 hydraulic oil? And can they be mixed?
Although both oils are used in hydraulic systems, they do not work in the same way. The main difference is how “thick” or “light” the oil is, and this affects how it flows within the equipment and the protection it offers.
Hydraulic oil 46 vs 68
ISO 46 and ISO 68 hydraulic oils are mainly distinguished by their viscosity, i.e., how light or thick they are when flowing within the system. This difference directly impacts how they behave under temperature, pressure, and load.
Difference between 46 and 68 hydraulic oil
In general, 46 oil flows better and is ideal for lighter equipment or equipment operating at higher speeds, while 68 oil offers superior protection in heavy machinery or machinery operating in very hot conditions. The choice between the two will depend on the type of operation and the environment in which the equipment is used.
Difference between 46 and 68 hydraulic oil in terms of viscosity
Viscosity determines how thick or fluid the oil is within the system. To understand this quickly, let’s look at the list:
- ISO 46: lighter oil; circulates more easily.
- ISO 68: thicker oil; better supports load and high temperatures.
In short: 46 performs better at lower temperatures, while 68 provides better protection in equipment that works hard or gets very hot, which is common in Puerto Rico.
Difference between 46 and 68 hydraulic oil in terms of behavior
Each grade behaves differently depending on the pace of work and temperature. Here are the key differences:
- Hydraulic oil 46:
- Works well in cold or moderate climates.
- Ideal for fast, low-load systems.
- Facilitates start-ups when the equipment has been turned off.
- Hydraulic oil 68:
- Maintains protection even when the system heats up.
- Recommended for heavy machinery or continuous use.
- Better withstands heavy loads and high pressure.
Difference between 46 and 68 hydraulic oil in terms of application
To make it easy to identify where each one goes, here is the list
- ISO 46 is used more in:
- Light agricultural equipment.
- Light manufacturing.
- Fast hydraulic systems with low loads.
- ISO 68 is most commonly used in:
- Excavators, forklifts, and construction machinery.
- Heavy industrial equipment.
- Systems that operate in high temperatures (such as in PR).
- Machinery that operates for long hours or under constant pressure.
Can you mix 46 and 68 hydraulic oil?
The short answer: it is not recommended. Although both oils can be mixed without causing a harmful reaction if they belong to the same type (e.g., AW), mixing alters the final viscosity, which can affect the pressure, lubrication, and efficiency of the hydraulic system. In other words, the resulting oil will be neither 46 nor 68, but something in between that may not be suitable for that equipment.
Mixing should only be done in emergencies, such as when the level is low and there is no immediate access to the correct grade. Even so, once the situation has been resolved, it is best to drain the system and replace all the oil to avoid premature wear or failure due to unexpected temperatures or loads.
Can you use 68 hydraulic oil instead 46?
In some cases, yes, but it is not always ideal. ISO 68 hydraulic oil can be used when machinery is operating under heavy loads, generates a lot of heat, or the manufacturer indicates that both grades are compatible. Under these conditions, 68 offers a more resistant lubricating film and greater protection.
However, it should not be used in systems that require a lighter oil to operate quickly or in automotive and agricultural equipment where the fluidity of ISO 46 is necessary. Oil that is too thick can cause loss of efficiency, overheating, and premature wear.
We always recommend checking the equipment or vehicle manual before making any viscosity changes to ensure safe and optimal operation.
How to choose between 46 and 68 hydraulic oil
Choosing the right grade doesn’t have to be complicated. The key is to assess how, where, and under what conditions your equipment operates. Here are the most important points to consider:
- Operating temperature. In Puerto Rico, where the climate is hot almost year-round, ISO 68 is usually the safest choice for heavy machinery or equipment that generates a lot of heat.
- Manufacturer’s recommendations. Each machine comes with clear specifications on which oil to use. Following these guidelines prevents breakdowns, overheating, and unnecessary repair costs.
- Type of work:
- Light and fast work: ISO 46
- Heavy or continuous work: ISO 68
- Operating environment. If the equipment is exposed to the sun, works in construction, mining, ports, or intensive agriculture, a more resistant oil such as ISO 68 is ideal.
ISO 46 vs ISO 68
Both oils work well in hydraulic systems, but each is designed for different conditions. ISO 46 is more fluid and better suited to light or fast-operating equipment, while ISO 68 offers greater protection in heavy machinery or hot environments. Therefore, they should not be interchanged without first assessing the operation and actual needs of the equipment.
Which hydraulic fluids meet ISO 46 and ISO 68 specs?
Oils that meet ISO 46 and ISO 68 specifications typically include:
- AW (Anti-Wear) hydraulic oils. Formulated to reduce wear and protect internal components.
- Premium hydraulic oils for industrial and mobile systems. Ideal for equipment that operates for long hours or under demanding conditions.
- Fluids with special additives. Designed to prevent corrosion, oxidation, and foaming, maintaining system efficiency.
In Puerto Rico, these grades are especially common in sectors such as construction, manufacturing, agriculture, and transportation, where heat, humidity, and continuous operation require reliable, high-performance lubricants.
Get the right hydraulic oil for your equipment with American Petroleum
At American Petroleum, we offer a wide variety of hydraulic oils designed to maximize the performance and service life of your machinery, especially under the hot and intense working conditions we face in Puerto Rico.
Our technical team can guide you in selecting the right grade for your type of operation, environment, and manufacturer’s recommendations. Ready to place your order? Contact us at info@americanpetroleumpr.com or check out our catalog here:
