Mobil Delvac 1 ESP 5W-40 is an advanced full synthetic oil specially formulated for diesel engines that works to extend engine life, fuel economy potential, and deliver long drain capability for modern diesel engines operating in severe conditions. Mobil Delvac 1 ESP helps to deliver exceptional performance with state-of-the-art technology to reduce engine deposits and sludge formation, as well as provide anti-wear and anti-scuff engine control. Provides excellent low-temperature performance for increased oil flow to critical engine surfaces at startup. Works to deliver outstanding protection against oil thickening and degradation, helping to reduce the number of oil changes. Recommended for - most engine generations up to the latest and most sophisticated high-performance diesel engines with turbocharger, direct-injection and low-emission designs, on-and-off highway applications operating in both high-speed/high-load and short-haul pick-up/delivery and in severe low-speed/heavy-load conditions, heavy-duty diesel engines using low-sulfur diesel fuels and many biodiesel fuel formulations, naturally aspirated and turbocharged, diesel-powered equipment, diesel-powered equipment from American and European builders, and refrigeration units. (Compared to an SAE 15W-40 engine oil. Actual savings are dependent on vehicle/engine type, outside temperature, driving conditions and your current engine oil viscosity.).