Tests Prove AMSOIL is the Best Diesel Engine Oil
Compare to Shell Rotella T, Mobil Delvac 1 ESP, Valvoline Premium Blue Extreme and Chevron Delo 400 LE
Improves Diesel Fuel Economy and Extends Oil Change Intervals for Diesel Engines Requiring API CJ-4 Oil

Built with the best additive and synthetic base oil technology, AMSOIL Premium Full Synthetic 5w40 Diesel Engine Oil (Product Code: DEO) exceeds the higher performance demands of modern engines. It is the premium choice for model year 2007 and newer heavy-duty and pickup truck diesel engines requiring an API CJ-4 diesel oil. Tests prove AMSOIL Premium Synthetic 5w40 Diesel Engine Oil is without a doubt the best diesel oil when compared to Shell Rotella T, Mobil Delvac 1, Valvoline Premium Blue Extreme and Chevron Delo 400 LE. (See graphs in Product Details below.)
AMSOIL Premium Synthetic 5w40 Diesel Engine Oil exceeds modern specs for emission-quality diesel oil. It is compatible with all diesel exhaust treatment systems and is designed to extend the service life of diesel particulate filters (DPF). It withstands the stress of heat, soot and acids to help prevent deposits, wear and corrosion. It is wax-free with a broad viscosity range to provide exceptional cold-weather starting and high-temperature protection.
AMSOIL Premium Synthetic 5w40 Diesel Engine Oil resists breakdown and offers maximum diesel fuel efficiency over extended oil change intervals. It can extend oil change intervals far beyond those recommended for conventional petroleum oils, providing maximum protection for up to three times the OEM-recommended oil change interval, even further with oil analysis. It delivers extraordinary lubrication in diesel engines found in commercial, fleet and personal vehicles. AMSOIL Premium 5w40 Diesel Oil is recommended for both diesel and, where appropriate, gasoline engines. API Licensed CJ-4, CI-4+, CF, SN, SM.
- Exceeds modern emission requirements
- Extends service life of diesel particulate filters (DPF)
- Resists soot contamination
- Reduces engine wear
- Maximizes diesel MPG
- Reduces oil consumption and emissions
- Resists sludge formation
- Ideal for winter and summer use
- Improves cold-temperature flow
- Engineered for 2007 and newer diesel engines requiring API CJ-4 emission quality oil standards
- Formulated for both diesel and gasoline engines
- Extended oil change interval three times the OEM recommendation
- API CJ-4, SN
Recommended Reading:
Diesel Fleet Fuel Economy Study (475.6 kb)
Diesel Fleet Fuel Economy in Stop-and-Go City Driving Conditions (354.6 kb)
Diesel Oil Viscosity (480.3 kb)