2001 Saab 9-3 Owner's Manual - Page 248

248 Technical data Viscosity: The viscosity of oil is classified according to the SAE standard. Nowadays, multigrade oils are always used in cars. The properties of these oils facilitate starting the car in cold weather but mean that the oil is also viscous enough to coat all moving parts under high pressures and with high outside air temperatures. Multigrade oils are graded with two viscosities, e.g. 10W-30, where the 10W meets certain viscosity requirements at -4°F (-20°C), while the 30 fulfills requirements at a temperature of 212°F (100°C). Under ACEA nomenclature, oils are divided into Class A for gasoline engines and Class B for diesel-engined passenger cars. There is a further class for heavy diesel engines. Each class is divided into three grades: 1, 2 and 3, where grades 2 and 3 normally encompass semi and fully-synthetic oils. The diesel class B also has a fourth grade, B4, which encompasses tests and regulations aimed at improving the performance of direct injection engines. In the same way as in the API system, gasoline and diesel engine specifications are combined for products that can be used in both types of engine. For example, a grade designation could be ACEA A2/B2 or ACEA A3/B3/B4. To afford Saab engines the best protection, with regard to lubrication, the ability to dissolve residues and the neutralization of combustion products, we recommend the following oil grades: • API SH/CD/CF or SJ/CD/CF. • ACEA A3/B3/B4. These oils contain the additives required for the engine to function well. We advise against the use of further additives.