The two-seat 1985 Fiero was Pontiac’s only attempt at a mid-engine sports car. One multi-viscosity oil was prescribed for most temperatures. When temperatures rose above or fell below the extremes of that range, though, the Fiero’s transversely mounted engine had specific requirements. This means you choose the oil based on the ambient temperature.
For temperatures from 100 to -20 degrees F, SAE 5W-30 oil is preferred. If the coldest temperatures are at or above 0 degrees F, however, you can use SAE 10W-30 oil. For temperatures above 15 degrees F, SAE 15W-40 oil will do. When the cold temperatures do not drop below 20 degrees F, use SAE 20W-20 oil and, if the coldest temperatures never drop below 40 degrees F, you can use SAE 30 single viscosity oil. Use oils with the API rating SF, or SF in combination with other letters, such as SF/CB or SF/SD. Don’t use oils with other API ratings.
