quote:I like the way Redline recommends drain intervals.
Red Line stands alone in the ability to provide extended drain intervals and lower friction and wear. Red Line Synthetic oils have been shown to last 25,000 miles in field tests; however we recommend shorter drain intervals in order to provide a margin of safety with the oil. We recommend draining the oil between 12,000 and 18,000 miles depending on the type of service and the degree of blow-by gases contaminating the oil. High-speed freeway driving is easy on the oil due to its excellent thermal stability. If the engine is worn and if considerable stop-and-go driving is involved, 10,000-12,000 mile drains are suggested. A good rule of thumb to follow is to change the oil at least once a year regardless the mileage. Manufacturers warranty requirements should be followed while under warranty. Filters can be changed every 5,000 to 7,500 miles in order to assure filter durability is not a problem. Red Line makes a 15W40 Diesel Engine Oil for diesel engines. The diesel engine oils contain significantly greater detergency and total base number (TBN) which helps keep the engine clean. This additional detergency is not recommended for gasoline engines since it could increase the tendency for spark plug fouling. Even though the Red Line Motor Oils meet the specifications for diesel engines, the Diesel Engine Oil should be used where extended drains (10,000 miles +) are required.