How often should oil be changed ?
- larger highway networks and a higher annual average of kilometers traveled,
- deterioration of city driving conditions.
- when the vehicle is not being used (for several hours), the engine oil sinks in the crankcase so that, on starting, it takes a certain amount of time (a few microseconds) to again reach all parts of the engine that need to be lubricated. Since a multigrade oil is more fluid at low temperatures, it reaches the various engine components more quickly than a monograde oil, thereby reducing wear on starting.
- Multigrade oil allow "saving fuel" around 1.5% to 3% then monograde oil
- Because lubricants collect particles of internal and external pollution (carbonic matter, particles of worn metal, ?)
- Because an oil?s efficacy diminishes because of : - dilution by water and fuel, - oxidation, - the consumption of additives, - shearing