How often, in kilometres and months
An independent reference of engine service intervals — oil, spark plugs, timing belt, coolant and air filter — with the kilometre, month, litre and degree limits for normal and severe driving.
Not a repair shop, not a parts store, and not a substitute for the owner's manual of your specific car. Nothing here is sold, booked or quoted.
Every 10,000–15,000 km or 12 months under normal driving — twice as often, 5,000–7,500 km, under severe duty.
The normal schedule assumes steady trips that let the engine reach its 90–105 °C operating range and stay there. Under those conditions oil holds its protective properties for 10,000–15,000 km, and the 12-month cap exists because time degrades oil even when the odometer barely moves.
Severe duty is the schedule for cars whose oil never gets a fair chance: repeated short trips, towing, or dusty roads. Any of those halves the interval to 5,000–7,500 km. Most city-driven cars, measured honestly, fall into this column for at least part of the year.
The oil filter is not a separate decision. A typical passenger-car engine holds 4–6 litres with the filter changed at every oil change, so the interval always means oil and filter together, never oil alone.
If most of your driving is short hops, towing or unpaved roads, the car belongs on the severe-duty schedule.
Normal driving means the engine regularly completes full warm-up: coolant at 90–105 °C, thermostat open at 80–95 °C, and enough running time at temperature before shutdown. Cars used this way can run the full 10,000–15,000 km oil interval and the full 15,000–30,000 km air filter interval.
Severe duty is defined by what the engine never achieves. A short trip ends before the operating range is reached, and dust works on two items at once: it shortens air filter life to about 10,000 km and pushes the oil interval down to 5,000–7,500 km. Towing adds sustained load, which belongs in the same column.
One warm-up habit matters here. Idling is the slow way to reach temperature; 3–5 minutes of gentle driving warms the engine faster than idling, which is why a driveway idle session does not count as a proper warm-up and does not move a car out of the severe column.
| Service item | Normal driving | Severe or hard use | Time limit or note |
|---|---|---|---|
| Engine oil | 10,000–15,000 km | 5,000–7,500 km | 12 months, whichever comes first |
| Oil filter | With every oil change | With every oil change | Part of every 4–6 litre refill |
| Air filter | 15,000–30,000 km | About 10,000 km | Dusty or unpaved roads shorten life |
| Spark plugs, nickel | 30,000–40,000 km | — | Electrode material sets the limit |
| Spark plugs, platinum | 60,000–100,000 km | — | Electrode material sets the limit |
| Spark plugs, iridium | 100,000–150,000 km | — | Electrode material sets the limit |
| Timing belt | 60,000–100,000 km | — | 5–7 years; a snap bends valves on interference engines |
| Coolant | 60,000–100,000 km | — | 2 years; 50/50 mix protects to about −37 °C |
Oil is the shortest interval on the car; everything else is measured in tens of thousands of kilometres or in years.
Spark plug life is set by electrode material. Nickel plugs are due at 30,000–40,000 km, platinum at 60,000–100,000 km and iridium at 100,000–150,000 km. The material is the interval: two identical engines can have plug schedules three times apart simply because they left the factory with different electrodes.
The timing belt answers to two limits at once: 60,000–100,000 km or 5–7 years, whichever comes first. This is the one interval where a failure is not gradual. On an interference engine a snapped belt lets pistons strike open valves and bends them, turning a scheduled replacement into an engine rebuild.
Coolant is due every 2 years or 60,000–100,000 km, and a 50/50 antifreeze-water mix protects the block down to about −37 °C. The air filter runs 15,000–30,000 km, dropping to about 10,000 km where roads are dusty or unpaved.
Intervals reflect widely published manufacturer and industry maintenance schedules for passenger cars.