Basically hydraulic fluid is the base fluid that is used in the different area of your vehicle that uses the force of the actual non-compressing fluid to create both a flow of force and protection. That is why the brake fluid, clutch fluid, and power-steering fluid, are all forms of specialized hydraulic oil.

There is a class of hydraulic fluids (DIN 51524) that contains dispersive and detersive additives much like engine oils. The use of these fluids is approved by many manufacturers and can offer several advantages in mobile equipment such as preventing varnish and sludge.

What’s the Difference Between the Hydraulic Oil and Motor Oil? Hydraulic oils are expected to have low compressibility, predictable friction and viscosity stability. Engine oils are intended to have high resistance to heat, resistance to absorption of fuels and chemical compounds produced during combustion.

Diesel fuel is thin, like water. If you mix the two, the hydraulic fluid will become thin. This will mess up the hydraulics, as the fluid will compress too much. This will make the hydraulics feel like there is an air bubble in the line.

What Happens when you put Diesel in a Gas Vehicle? Since diesel fuel is thicker and denser than gasoline, the fuel pump will struggle to move the diesel/gasoline mixture through the system. Also, the diesel will not be able to easily pass through the fuel filter. Instead, it will clog up the fuel filter.

DEF is a water-based fluid, which does not mix well with oils. Introducing DEF into engine, transmission or hydraulic oils can lead to an emulsion or separation of layers within the oil reservoir. This can cause inefficient oil flow, or damage to the oil pump or system components.

If it is a small hand-operated hydraulic jack, you can use ATF. Otherwise, refrain from using it. Therefore, to ensure maximum efficiency of the jack, use the proper fluid specifically produced for a hydraulic jack. The warranty for a specific jack specifies the fluid to be used.

It is generally inadvisable to use anything other the manufacturers’ recommended fluid or oil in any system. While power steering fluid and automatic transmission fluid are both hydraulic fluid based, the additives they contain may not be compatible with the seals in your jack.

Power steering fluid is one type of hydraulic fluid but is not the type normally used in a jack. The term “hydraulic fluid” is a general term that would refer to any fluid used in a hydraulic system. There are many different hydraulic fluids. Depending on the use, they can be mineral, synthetic, or even water based.

Hydraulic fluid will probably work as power steering fluid, however, using anything other than fluids recommended by the manufacturer may cause undesirable operation.

Although a “universal” power steering fluid may be satisfactory for many applications, some vehicles do require special additives for seal and pump lubricity, and corrosion protection. The type of power steering fluid that is specified for your vehicle should be marked on the PS reservoir or filler cap.

Brake fluids today are mostly glycol-ether based, but there are also mineral oil and silicone-based fluids available. The most commonly used power steering fluid substitute is automatic transmission fluid (ATF).