Royal Purple Duralec Super 15w-40 motor oil is high-performance engine oil made for emission-controlled diesel engines utilizing emissions equipment such as DPF’s, Catalytic Converters, EGR, and SCR injection. Royal Purple Duralec Super 15W-40 and 10W-30 are API CJ-4 engine oils.

Royal Purple Duralec Super motor oil is specifically formulated to maximize component life, extend drain intervals and improve fuel performance. These premium lubricant formulations provide excellent high-temperature resistance and low-temperature pumpability, outstanding soot dispersancy, improved rust and corrosion protection, and prevention of varnish and sludge formation.