Pro Series Diesel Engine Oil CK-4 in 15W40 and 5W40: 100% synthetic, extended-service diesel oil for trucks that work and tow. Excellent wear protection and high-temperature stability, prevents sludge and varnish, exceptional corrosion protection and improved fuel economy, with longer drain intervals than conventional oils. Compatible with other conventional and synthetic oils. Meets or exceeds API CK-4, CJ-4, CI-4 PLUS, CI-4 and CH-4, plus API SN, SM, SL and SJ for mixed gas/diesel fleets. Call or write with fitment questions.
