Duralec Ultra Diesel Motor Oil

Duralec™ Ultra™

Maximum Performance Motor Oil

Royal Purple Duralec Ultra motor oil is specifically formulated to maximize performance and meet the demands of today’s heavy-duty engines. Duralec Ultra is fortified with a high level of zinc/phosphorus anti-wear additive and Royal Purple’s proprietary Synerlec® additive technology.

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Technical Specifications

Synerlec creates a tenacious ionic bond with metal surfaces, which protects engines by providing instant wear protection upon startup. This state of the art technology also responds to increased pressure with increased film strength and improves the condition of metal-to-metal contact under severe conditions for greater protection.

Duralec Ultra provides a lower coefficient of friction to save fuel and its synthetic solvency keeps internal engine parts cleaner than detergents alone. With superior oxidation stability that greatly extends drain intervals and minimizes harmful oil degradation, Duralec Ultra outperforms leading synthetics and conventional lubricants for both gasoline and diesel engines.

Duralec Ultra motor oil is recommended for use in both two-cycle and four-cycle diesel applications including automotive, commercial fleet and stationary industrial diesel engines.

Available Viscosities



Versions of this product are also available from Royal Purple Industrial and Royal Purple Consumer.