Truegard AW 46 Hydraulic oil Zinc free- 55 GALLON DRUM

ISO VG 46 means the oil has a kinematic viscosity of approximately 46 cSt at 40°C, placing it in the medium-weight range for hydraulic fluids. It is commonly specified for industrial and mobile hydraulic systems operating at moderate temperatures and pressures - always check your equipment manufacturer's manual for the recommended ISO viscosity grade before selecting a fluid.

Zinc-based anti-wear additives can react with yellow metal components - such as brass, bronze, and copper alloys commonly found in pumps, valves, and fittings - leading to corrosion or deposit buildup. Many OEMs and system designers explicitly prohibit zinc-containing fluids in these applications, so an ashless, zinc-free formulation is required to maintain component integrity and system cleanliness.

Mixing zinc-containing and zinc-free hydraulic fluids is generally not recommended, as it can compromise both additive packages and reduce overall performance. Best practice is to fully drain and flush the hydraulic system before filling with this zinc-free formulation to avoid additive incompatibility.

Even when viscosity grades match, blending hydraulic fluids from different formulation types (e.g., zinc-free with zinc-based, or different base oil types) risks additive interaction, reduced anti-wear performance, and potential deposit formation. It is always safest to avoid mixing and to use a single, consistent product in your system.

Ashless additive systems are generally more thermally stable and less prone to forming sludge or metallic deposits than some conventional metallic-additive fluids, which helps preserve fluid integrity over longer service intervals and keeps hydraulic circuits cleaner. This stability also helps protect sensitive components and reduces the frequency of fluid changes.