How often should you change engine oil? A practical guide

The debate over how often to change engine oil has refused to die for decades: some swear by 5,000 km intervals, others are convinced modern engines on synthetic oil can comfortably stretch to 15,000. Even among experts, opinions diverge.

A short video by a Honda technician has lit up the discussion again. He showed two engines side by side: one serviced every 8,000 km, the other at 15,000 km. The contrast was hard to miss: the shorter-interval motor looked noticeably cleaner, while the more frugal approach left a distinct dark film and an unpleasant orange tint that many attributed to faster oil aging and resulting deposits.

The comments erupted, predictably. Part of the audience argued for 4,000–6,000 km to feel more at ease, while others said that with the right synthetic it’s just overspending. The underlying point is clear: the harsher the operating conditions, the shorter the interval should be. Stop-and-go traffic, short hops, cold starts, heat, spirited driving and sustained high revs drain oil life faster. And the price of an extra change is often trivial compared with what an engine repair can cost.

A practical middle ground for most cars is to refresh the oil a bit sooner than the service book’s upper limit, especially if you want trouble-free ownership. Many mechanics name 8,000–10,000 km as a sensible window for mainstream engines, while 15,000 km tends to be appropriate only with ideal usage and high-quality oil carrying the manufacturer’s approvals. And, of course, it’s critical to pour exactly the viscosity and specification listed in the owner’s manual. In real life, erring on the cautious side rarely disappoints.