A lubricant additive dispensing apparatus comprising a tubular housing extending between a fluid supply side and a fluid discharge side, wherein each side is sealed by a respective end wall. A volume of fluid additive is stored within a fluid additive storage cavity formed within the tubular housing. Fluid enters the lubricant additive dispensing apparatus, wherein a first portion of the fluid passes therethrough and a second portion of the fluid is directed towards a piston cap attached to a compression spring. The second fluid portion applies a compression force to the piston, interacting with the generated expansion force of the spring to cause the piston cap to oscillate. The piston cap is in communication with the fluid additive, applying an oscillating pressure thereto, causing a controlled volumetric rate of dispensing of the additive into the fluid.