What the rest of the world calls engine oil, in Bangladesh, it's known as mobil with a lower case M. Goes to show which brand has been dominating the scene for decades. So what does it do? Apparently, most car owners, drivers and many service station personnel seem to think it keeps things slippery - similar to pouring a little coconut oil in a padlock to keep it from rusting. Nope.

What does engine oil really do?

Simply put, it makes sure things stay cool and clean. Engine oil reduces friction between moving parts. Friction creates heat, heat creates things to reach temperatures high enough for engine internals to melt. It also contains cleaning agents that help to keep the insides free of sludge.

What's sludge?

As petrol burns, it leaves behind sticky, icky by products known as sludge. This ends up lining the inside of engines causing clogs and corrosion as you race across Purbachal 300ft trying to impress virtually nobody. The latter part we suggest not to do.

How are we killing our cars?

Using the wrong engine oil grade and not getting it changed at right intervals. Engine oil comes in various types and weights. And over time, it breaks down. More on that later.

Can I put in any oil?

Different cars require different oils based on temperature and type of car. Most modern engines often require a lighter oil. An older, classic car requires thicker mineral oils. How do you know which is required? Simple. Google it. Look in the owner's manual. And for the most popular car in Bangladesh, the Toyota Allion, it generally requires 5W-30 or 10W-30 oil. Not the 20W-50 most garages end up pouring. Use the right oil. Newer cars don't like thicker oils.

Follow us for more on how to make your car last nearly forever. More details on engine oil coming. Mail shift@thedailystar.net with your queries.