Throat Seal Liquid (TSL) prevents paint and coatings from drying onto the displacement rod and packings, extending the life of the pump.
Graco TSL is specially formulated to dissolve material on displacement rods and prevent friction, wear or abrasion from dried pigment particles. Motor oil is not a substitute for TSL.
Apply a few drops as needed, do not over apply. Over application may lead to TSL entering the pump and contaminating your coating. May cause cratering, fish eyes, or hinder coating integrity.