Short answer: the pump sets the fluid. Gear pumps are the most forgiving on viscosity, vane pumps need the viscosity held in a tighter window, and piston pumps demand anti-wear protection and the right grade the most. Every pump maker prints the acceptable viscosity range – stay inside it.

GEAR PUMPS

The workhorse. Gear pumps tolerate a wider viscosity range and shrug off conditions that stress tighter designs. Most mobile and industrial gear-pump systems run fine on AW46, with AW32 for cold starts and AW68 for hot, heavy service.

VANE PUMPS

Vane pumps rely on a thin oil film between the vanes and the cam ring. Too thin and the vanes wear fast; too thick and the vanes stick at startup. Keep vane systems in the middle grades – usually ISO 32 to 68 – with anti-wear additives, and keep the oil clean.

PISTON PUMPS

The tightest tolerances and the highest pressures. Piston pumps need anti-wear hydraulic oil at exactly the specified viscosity, with the best filtration of the three. Skimping on grade or cleanliness here is the most expensive shortcut in hydraulics.

WHEN IN DOUBT

The pump or machine manual lists the acceptable ISO grades and often the exact products. Send us the pump make and model, or the manual line, and we confirm the grade before you order.

GET PRICING

AW32, AW46 and AW68 in 5-gallon pails, 55-gallon drums or bulk, delivered across NYC, Long Island, New Jersey, Westchester, Pennsylvania and the Tri-State. Office hours Monday-Friday, 6:30 AM to 4:00 PM. Bass Oil & Chemical LLC, 126 Scott Avenue, Brooklyn, NY 11237. Serving Brooklyn fleets since 1988. (718) 628-4444.