Traffic, heat and dust: how severe conditions affect engine oil

Short trips

In 5–10 minutes an engine doesn’t warm up. Water condenses on the cold cylinder walls and some fuel slips into the crankcase. On a long drive this evaporates; on short trips it builds up and thins the oil. If the car mostly goes to the shop and back, a 20–30 minute drive without stops once a week helps.

Traffic and idling

In traffic the odometer barely moves while the engine runs, heats up and collects combustion by-products. The radiator gets little airflow when standing still, so with the air conditioning on the oil runs hotter than on the move. For the oil, an hour in traffic is harder than an hour on the highway.

Heat

In an Uzbek summer the air reaches +40 to +45 °C and the asphalt gets hotter still. The cooling system keeps the engine temperature in check, but with less margin, and the oil stays hot for longer. Hot oil oxidises faster: it darkens, thickens and cleans less well.

You still don’t need a different viscosity for summer. It matters more that the oil is fresh and meets the specification. Before the heat arrives, check the coolant, clean the radiator and make sure the fan works.

Dust

Fine loess dust gets past a worn or badly fitted air filter into the cylinders and from there into the oil, where it acts as an abrasive. In the dusty season and after driving on unpaved roads, check the air filter more often than the schedule says.

What to do

• Use the “severe” service schedule from your manual; it is usually one and a half to two times shorter than the normal one.
• Check the oil level every week or two, especially in summer.
• Use oil with the approval your manufacturer requires, and don’t move to a thicker grade “just in case”.
• After a long run at high revs, let a turbocharged engine idle for 30–60 seconds before switching off.
• Replace the air filter by its condition, not only by mileage.