6BTA, 6CTA, QSB5.9 Aftercooler O-Ring – PART #3919853

Genuine Cummins Aftercooler O-Ring, “Thin Style” Used on Most 6BTA’s, & All 6CTA, QSB5.9, QSL9’s.Fits all Horsepower models. Not for MOTA Coolers. For reinstalling 6BTA and QSB5.9 aftercoolers, 3969988 Gasket(s) are required. Typically Qty 2 for 6BTA and Qty 1 for QSB (LINK OR CHECKBOX)