How to Select Lubricating Oil
Fig. 1, Example SAE Viscosity Grade: 15W-40 API Classification: CI-4 PLUS
Cold Weather Starting
At ambient temperatures below -10° C (14° F), SAE 5W-30, 5W-40, or 10W-40 oils may be used, provided they are API CI-4 PLUS and have demonstrated field performance in Detroit™ engines. These oils must possess a High Temperature / High Shear Viscosity of 3.7 cP minimum.
Use of Synthetic Oils
Synthetic oils may be used in Detroit™ engines provided they are approved by a POWER GUARD® Oil Specification (PGOS) 93K214. The use of synthetic oils does not necessarily ensure the extension of the recommended oil drain intervals beyond the limits. Synthetic oils offer improved low-temperature flow properties, high-temperature oxidation resistance, and improved fuel mileage. However, they are generally more costly than non-synthetic oils.
Product information about synthetic oils should be reviewed carefully. Performance additive systems often respond differently in synthetic oils.
Use of Supplemental Additives
Lubricants meeting the Detroit™ specifications outlined in this publication already contain a balanced additive treatment. Supplemental additives are generally not necessary and can even be harmful. These additives may be marketed as either oil treatments or engine treatments and are discouraged from use in Detroit™ engines.
Engine damage resulting from the use of such materials is not covered by your Detroit™ warranty. Detroit™ will not provide statements beyond this publication relative to their use.