Hydraulic Oil

Repco offers a dependable range of hydraulic oil products suited to home garages, trade workshops, and rural properties. Whether maintaining a vehicle hoist, servicing a trolley jack, or topping up machinery, selecting the correct hydraulic fluid helps ensure smooth operation and consistent pressure control. The range includes common grades such as iso 46 hydraulic oil, which is widely used in automotive lifting equipment and general workshop applications. For smaller equipment, a quality hydraulic jack oil supports safe lifting and controlled lowering during brake, suspension, and tyre work.

With clear specifications and practical pack sizes available, Repco makes it straightforward to match the right product to the job and keep essential equipment operating as intended.

Hydraulic oil plays a critical role in transferring power, lubricating internal components, and protecting hydraulic systems from wear and corrosion. Whether servicing a vehicle hoist, topping up a hydraulic jack oil reservoir, or maintaining farm equipment, selecting the correct hydraulic fluid helps ensure consistent pressure, smooth operation, and long service life.

In automotive and workshop environments, hydraulic fluids are exposed to fluctuating temperatures, heavy loads, and extended operating hours. Using the right grade and specification reduces internal leakage, minimises seal deterioration, and supports reliable performance across a range of machinery.

Does it matter what hydraulic oil you use?

It does matter what hydraulic oil you use. Hydraulic systems are engineered with specific viscosity requirements and additive packages. Using the wrong product can lead to reduced efficiency, increased wear, overheating, and premature component failure.

Most workshop equipment specifies an ISO viscosity grade such as hydraulic oil 32, hydraulic oil 46, or hydraulic oil 68. These numbers refer to the oil’s viscosity at 40°C. For example:

• ISO 32 hydraulic oil has a viscosity of approximately 32 centistokes at 40°C.
• ISO 46 hydraulic oil has a viscosity of approximately 46 centistokes at 40°C.
• ISO 68 hydraulic oil has a viscosity of approximately 68 centistokes at 40°C.

If a vehicle hoist manufacturer specifies iso 46 hydraulic oil, substituting it with a lighter iso 32 hydraulic oil may reduce film strength under load. Conversely, using thicker hydraulic oil 68 in a system designed for 46 hydraulic oil may slow response times in cooler conditions.

Hydraulic fluids also contain anti-wear additives, oxidation inhibitors, rust protection agents, and anti-foam components. These additives help maintain stable operation under pressure, particularly in equipment such as press tools and lifting platforms.

Is hydraulic oil the same as hydraulic fluid?

The terms hydraulic oil and hydraulic fluid are often used interchangeably, but there is a technical distinction. Hydraulic oil usually refers to mineral-based oil formulated specifically for hydraulic systems. Hydraulic fluids is a broader category that can include mineral oils, synthetic fluids, and water-based formulations.

In most automotive garages and home workshops, mineral-based hydraulic oil is the standard choice. It provides reliable lubrication, seal compatibility, and corrosion resistance at a practical cost. Synthetic hydraulic fluid may be specified in specialised industrial applications where extreme temperatures or fire resistance are critical.

For common automotive tasks such as servicing a trolley jack or maintaining a hydraulic engine crane, a quality mineral hydraulic jack oil or general-purpose iso 46 hydraulic oil is typically appropriate, provided it meets the equipment manufacturer’s requirements.

What kind of oil goes in a hydraulic?

The type of oil that goes into a hydraulic system depends on the design, load capacity, and operating environment. In most automotive and light industrial settings, the following grades are common:

• Hydraulic oil 32 for cooler climates or lightly loaded systems.
• Hydraulic oil 46 for general workshop use and moderate temperatures.
• Hydraulic oil 68 for higher load applications or warmer operating conditions.

For example, a hydraulic jack oil reservoir in a home garage often performs well with hydraulic oil 32 or hydraulic oil 46, depending on ambient temperature. In contrast, larger workshop hoists and presses frequently specify 46 hydraulic oil or 68 hydraulic oil for improved load-bearing capacity.

It is important not to confuse hydraulic oil with universal tractor transmission oil or tractor transmission oil. While these products may serve combined hydraulic and transmission systems in agricultural machinery, they are formulated differently and are not direct substitutes for standard hydraulic oil in workshop equipment unless explicitly specified.

Which hydraulic oil is thicker, 32 or 46?

ISO 46 hydraulic oil is thicker than ISO 32 hydraulic oil at the standard reference temperature of 40°C. The higher the ISO number, the greater the viscosity.

Viscosity affects how the oil flows through pumps, valves, and cylinders. In cooler climates, iso 32 hydraulic oil flows more readily during start-up, reducing strain on pumps. In warmer regions or under sustained heavy loads, iso 46 hydraulic oil maintains a stronger lubricating film.

Choosing between hydraulic oil 32 and hydraulic oil 46 should be based on manufacturer guidance and operating temperature. In Australia’s varied climate, workshops in cooler southern regions may favour 32 grade for light-duty equipment, while facilities in warmer areas may select iso 46 hydraulic oil for consistent performance year-round.

For heavy-duty presses, log splitters, or commercial hoists, iso 68 hydraulic oil may be specified. Its higher viscosity supports systems that operate under greater load and heat.

What type of machines would use hydraulic oil around the garage, workshop or home?

Hydraulic oil is commonly used in:

• Hydraulic trolley jacks and bottle jacks
• Vehicle hoists and car lifts
• Engine cranes and transmission jacks
• Hydraulic presses
• Log splitters
• Tractors and certain agricultural attachments

In a home garage, topping up hydraulic jack oil ensures smooth lifting and controlled lowering when performing brake servicing, suspension work, or tyre rotation. In a professional workshop, maintaining correct hydraulic fluid levels in hoists is essential for safe daily operation.

On rural properties, tractors may use tractor transmission oil or universal tractor transmission oil in combined hydraulic and transmission systems. These applications require careful adherence to manufacturer specifications, as the fluid must provide hydraulic performance, gear protection, and wet brake compatibility.

Best Practices for Automotive Use

Before adding or replacing hydraulic oil, clean around filler caps to prevent contamination. Use a clean funnel, and avoid mixing different viscosity grades unless approved. Check seals and hoses for leaks, and inspect oil condition for signs of contamination, such as milky appearance or debris.

Regular inspection of hydraulic fluids supports safe lifting, stable operation, and predictable system response. Selecting the correct grade, whether hydraulic oil 32, hydraulic oil 46, or hydraulic oil 68, protects equipment investment and supports reliable workshop performance. By matching viscosity and specification to the task, both home users and experienced technicians can maintain safe, efficient hydraulic systems across a wide range of automotive applications.

Complete the Job with the Right Fluid Transfer Products from Repco

Choosing the right hydraulic oil is only part of maintaining reliable equipment. Repco also stocks workshop consumables, tools and garage equipment, and oils and fluids to support safe and efficient servicing. Clean funnels, drain pans, and measuring jugs from the tools and garage equipment category help prevent contamination when handling hydraulic fluid. Workshop consumables such as gloves, rags, and spill control products assist with clean and responsible maintenance. Pairing iso 46 hydraulic oil or hydraulic jack oil with the right supporting products helps maintain lifting gear, presses, and other hydraulic systems with confidence, whether working at home or in a professional workshop.