Cummins 6C 8.3L Engine Oil Cooler Core - Used

Application: Cummins 6C / ISC / QSC 8.3L (and related ISL 8.9L) diesel engine oil cooler core / bundle — the stacked-plate heat exchanger element that bolts to the side of the block. Commonly cross-referenced to Cummins P/N 3974815, 3966365, and 5284362. Condition: Used take-off, sold as a core / rebuild candidate. One face shows heavy surface rust; other face is cleaner with visible plate brazing but has scale, staining, and light pitting. Not pressure tested. Buyer must confirm fitment by part number, photos, dimensions, engine model, serial number, and application before purchase. Used marine part sold as-is unless otherwise stated. No returns on electrical, used, special-order, or installed parts.