How often to change your oil
How manufacturers calculate the service interval, and which operating conditions shorten it.
- How often to change the oil? Why there is no universal oil change interval, and how to move from the service book figure to your own, allowing for traffic jams, dust and fuel quality.
- Manufacturer recommendations What the service interval in the service book means: it is set for average conditions, given in kilometres and months, and may depend on the country of sale.
- How do manufacturers calculate the interval? Why the oil change interval a carmaker recommends is calculated around the warranty period and marketing, not around a long engine life.
- Oil change interval (Longlife) Three conditions for extended Longlife intervals: the carmaker allows it, this oil is approved for the engine, and your driving conditions are within limits.
- What factors shorten the service interval? What “severe conditions” mean for engine oil: idling, short trips, traffic jams, heavy loads, dust and poor fuel, plus new risks for turbo and hybrid engines.
- How to determine the oil change interval? When to halve the recommended engine oil change interval, and why a used car with an unknown history needs more frequent oil changes in its first year.
- Oil change intervals today: Longlife, the service indicator and short trips How the car works out its own oil change date, why the figure on the dashboard is a maximum, and what shortens the interval in a modern engine: fuel in the oil, bioethanol, stop-start.
- On oil change frequency An introduction to oil change intervals: there is no universal answer, only the carmaker’s recommendation and outside factors that shorten oil life.
- In brief: about “snowdrops”... A tip for cars that sit unused all winter: start the engine and warm it up fully once a week, and change the engine oil in spring before setting off.
- In Brief: The “Weekend” Car... A car should be driven every day: if it is used only at weekends, change the engine oil more often than the recommended interval says.
- In brief: about traffic jams... Why city traffic jams are severe conditions for an engine: the oil oxidises and collects dust and fuel, so change it more often than the schedule says.
- Hybrids and oil: does the engine really hardly ever run? Why oil in a hybrid does not age any slower: short starts without warm-up, water and fuel in the sump, the dipstick, 0W-16 and 0W-8 oils, the interval.