Your engine is a large piece of metal, containing numerous other metal parts that move and possibly collide with each other. Here’s a look at the fundamental ways oil protects your engine, as well as the fascinating sciences involved in making sure your engine doesn’t break down.
1. What exactly does motor oil do?
There are a few reasons why it is important to top up your car engine with oil. First and foremost, it lubricates all moving metal parts so they don’t grind together and cause unnecessary wear or too much heat. Oil also contains all the nasty byproducts of combustion. In the long run, keeping your oil level up will save you money on repairs and even give you a very small improvement in your fuel economy as the engine won’t work as hard.
Over time, your engine will pick up dirty deposits, meaning it won’t last forever. If you’re wondering how often you should change your oil, check your car’s owner’s manual. It will probably be somewhere in the neighborhood of every 10,000 miles for a modern car – please disregard the myth of 3,000 miles! You don’t need to change your oil as often.
2. What does that alphanumeric rating actually mean?
Motor oils are rated in two ways: cold viscosity and warm viscosity. This rating is displayed on the bottle and gives you an idea of how well it will respond to cold startups — especially important for those living in colder climates — and how thick it is in high temperatures.
The first number added to the letter “W” (which stands for “Winter”) is the cold rating. The lower the number, the lower the temperature in which it operates. If the number is too high and you try to start your car in freezing temperatures, the oil may be too thick to flow and your engine may not start.
The second number is the viscosity of the oil when tested at temperatures indicative of a running engine. The higher the number, the thicker the oil. If you run your motorcycle at high speeds or under heavy loads, such as with a trailer, you’ll want a higher number. Your car owner’s manual will tell you which viscosity oil to use.
3. What is the difference between synthetic and mineral oils?
A mineral oil is essentially the same as when it was extracted from the ground, while synthetic oils have been distilled and broken down into their basic molecules. They can then be rebuilt, with molecules modified to provide better protection. Mineral oils are cheaper, but also contain more impurities and do not provide such a smooth lubrication.
4. Synthetic engine oil is more than just engine oil
The great thing about fully synthetic oils is that clever scientists in labs can add to the makeup of the oil to provide better anti-wear, anti-oxidant and anti-corrosion properties. Once the base oil is in place, they usually add zinc, phosphorus and sulfur molecules.
5. Adding metal to the engine oil reduces friction
It sounds counter-intuitive, but some oil companies have had success adding titanium to the oil. When you turn off your engine, the oil drains from the engine back into the pan. Adding titanium helps it bond to the metal parts, ensuring there’s a little layer of protection the next time you turn your engine on—that’s when 75 percent of engine wear occurs—before the oil has had a chance to through it and go to full operating temperature.
6. Magnetic particles reduce wear
Another way oil manufacturers have found that they can reduce wear at startup is by adding magnetic particles to the oil mixture. When the engine is turned off, the magnetic particles adhere to the engine to reduce wear on start-up.