It is the weight of the multi-vicosity oil. The 10 is the weight of the oil when cold. The W stands for Winter. The 40 is the weight of the oil when it gets hot.
It is a multi-viscosity oil that is 5 weight when it is cold and becomes 30 weight when it is hot.
Multi-Grade or Multi-Weight oil is oil that has additives added to change viscosity of the oil at different temperatures. This allows the oil to flow differently at hot or cold temperatures. This type oil is designated with 2 numbers. The first number is followed by the letter W. The first number indicates the weight of the oil in cold temperatures (Winter). The second number indicates the weight of the oil in normal (hot) temperatures. This multi-weight allows the oil to flow easily when it is cold which protects the engine from excess wear when it is started when it is cold. It then thickens when it is hot to allow for better protection of a hot engine.
Most likely that the manufacture has recommended a W5-30 multi viscosity oil for Saturn. The reason for multi viscosity is, it is tested to protect the engine like a 30 weight oil but act like a 5 weight oil. In all of my vehicles I use 30 weight period, not a Multi Viscosity. If you try this and then experience tougher starting in colder months I would suggest reverting back to the W5-30.
Yes you can but find out what weight the manufacturer recommends first. Some recommend a straight weight instead of a multi weight oil.
The "W" stands for weight. The "W" stands for winter. 5w30 is a multi viscosity oil. It acts like both 30 weight in warm weather, and 5 weight oil in cold weather.
I NEVER USE A MULTI GRADE OIL I USE A STRAIGHT 30 WEIGHT DETERGENT
SAE 50 is a single weight oil that is 50 weight when cold or hot. SAE 20w50 is a multi-grade oil. When cold it flows as a 20 weight oil and therefore flows much easier. At full operating temperature it flows as a 50 weight oil. The W stands for winter.
Use exactly what the manufacture of your vehicle recommends. All manufactures recommend a multi weight oil such as 5w-20 as an example. These oils are 5 weight at startup and 20 weight when the engine gets warm.
I dont know why you would want to do that. The multi viscosity and straight weight oils wont mix and the multi viscosity oil will be expended faster when it is at its low end. If they happen to reach the correct temperature together, they will flow as united and become the same weight but never be homogenous.
The operator's manual for a 3020 should state which weights of oil should be used in specific temperatures. Generally a 30# oil should be used in the summer and a 10# oil in the winter. A Multi-weight oil such as 15W-40 can also be used in all seasons.
You should use a 30-weight motor oil, NOT a multi-grade such as 10-W-40. Use of multi-grade oil will increase your oil consumption considerably. Check your owners manual, nearly all Briggs engines made in the last 10 years recommend a multi-viscosity oil, namely 10w30. However, if not used below 40 degree temperature's, 30w detergent oil is fine as it is shear stable (will not degrade to a 20w under high heat).