We tested the 1252970 Core AS Oil Cooler for Cat 3066 engines—see the highlights and what to expect in real operation. This video walks you through the part’s role in heat exchange, stable oil temperature control, and component protection for 318C, 320C, 320D, 321C, and 323D excavators. Watch a close-up inspection, fitment overview, and practical maintenance insights to help you evaluate replacement decisions with confidence.