While all of your engine’s fluids are important, the vital one is oil.
If you run out of gasoline, your car will start again once you’ve refilled the tank, and as drag cars prove, you can run for a short period of time without coolant (although it’s not recommended, of course). But run out of oil, and your engine could turn into a square of scrap in not much longer than it takes you to read this paragraph.
With oil doing such an important job under your hood, it’s important to know a bit more about this essential fluid.
What does it do?
Oil lubricates the moving parts in your car’s engine, some of which are only a few thousands of an inch apart. It also helps to remove heat from the engine’s high-temperature combustion area, inhibits corrosion, reduces engine wear, and suspends dirt particles so they don’t settle in and clog up those moving parts.
To make engine oil, manufacturers first distill crude oil into four products according to each one’s boiling point, a process called fractional distillation. The lowest grade is asphalt. Base oil, which is the lubricating variety, is next up, followed by diesel and home heating oil, and then gasoline.
These base oils are further separated by their individual boiling points, which produce the higher and lower viscosity grades. We’ll come back to that, because it’s important. A bottle of engine oil contains about 80 per cent base oil, with the remaining 20 per cent made up of various additives such as dispersant, anti-wear agents, antioxidants, and detergents.
'Conventional' versus…?
At one time, all engine oils were “conventional” oils, distilled and packaged straight from crude oil. Now you’re more likely to see synthetic oils on the shelf. The name sounds like they’re made from non-petroleum ingredients, but in reality, most synthetic oils are made from base oils that are distilled from crude. The difference is that synthetic oil’s base stock is of higher quality than that used in conventional oil, and it undergoes a synthesis process that produces consistently-shaped molecules for improved lubrication and flow. Fully synthetic oil also contains additives that are not distilled from crude oil.
Because both are crude-based, it’s safe to mix synthetic and conventional oils when necessary, such as topping up your engine, and it’s also safe to switch from one to the other when doing an oil change. Switching to synthetic will not cause an engine to leak or experience blow-by (when oil slips by the piston rings and into the combustion chamber).
With oil doing such an important job under your hood, it’s important to know a bit more about this essential fluid.
What does it do?
Oil lubricates the moving parts in your car’s engine, some of which are only a few thousands of an inch apart. It also helps to remove heat from the engine’s high-temperature combustion area, inhibits corrosion, reduces engine wear, and suspends dirt particles so they don’t settle in and clog up those moving parts.
To make engine oil, manufacturers first distill crude oil into four products according to each one’s boiling point, a process called fractional distillation. The lowest grade is asphalt. Base oil, which is the lubricating variety, is next up, followed by diesel and home heating oil, and then gasoline.
These base oils are further separated by their individual boiling points, which produce the higher and lower viscosity grades. We’ll come back to that, because it’s important. A bottle of engine oil contains about 80 per cent base oil, with the remaining 20 per cent made up of various additives such as dispersant, anti-wear agents, antioxidants, and detergents.
'Conventional' versus…?
At one time, all engine oils were “conventional” oils, distilled and packaged straight from crude oil. Now you’re more likely to see synthetic oils on the shelf. The name sounds like they’re made from non-petroleum ingredients, but in reality, most synthetic oils are made from base oils that are distilled from crude. The difference is that synthetic oil’s base stock is of higher quality than that used in conventional oil, and it undergoes a synthesis process that produces consistently-shaped molecules for improved lubrication and flow. Fully synthetic oil also contains additives that are not distilled from crude oil.
Because both are crude-based, it’s safe to mix synthetic and conventional oils when necessary, such as topping up your engine, and it’s also safe to switch from one to the other when doing an oil change. Switching to synthetic will not cause an engine to leak or experience blow-by (when oil slips by the piston rings and into the combustion chamber).
However, while synthetic oil won’t create the problem, it can make it worse if the engine was already leaking.
Viscosity 101
Now … about the importance of viscosity. Oil gets thinner as it gets hot, reducing its ability to protect the engine, and becomes thicker in the cold, which can make it harder to start the engine. To get around this problem, manufacturers mix different viscosities of oil to produce multi-grade blends.
Viscosity is indicated by numbers. A lower number means oil that will remain fluid at low temperatures, while a higher number is oil that will stay thick enough when it gets hot. The percentage of higher or lower viscosity in the blend determines the optimum use for the oil.
The first number on the blend indicates the oil’s cold-weather performance, with a lower number meaning it can take colder temperatures. The W in between the two doesn’t mean Weight, as many people believe, but Winter. The number after the W indicates how well the oil handles hot weather, where a higher number is best.
Viscosity 101
Now … about the importance of viscosity. Oil gets thinner as it gets hot, reducing its ability to protect the engine, and becomes thicker in the cold, which can make it harder to start the engine. To get around this problem, manufacturers mix different viscosities of oil to produce multi-grade blends.
Viscosity is indicated by numbers. A lower number means oil that will remain fluid at low temperatures, while a higher number is oil that will stay thick enough when it gets hot. The percentage of higher or lower viscosity in the blend determines the optimum use for the oil.
The first number on the blend indicates the oil’s cold-weather performance, with a lower number meaning it can take colder temperatures. The W in between the two doesn’t mean Weight, as many people believe, but Winter. The number after the W indicates how well the oil handles hot weather, where a higher number is best.
A 5W-30 blend is generally the appropriate oil for winter use in average climates. For summer, switching to 10W-40 will provide better protection as the temperature soars. These ranges are among the most common, but there are extreme viscosity ratings, such as 0W for very cold climates, or 60 for very hot ones.
What about changing your oil?
What about changing your oil?
Improved oil formulas and engine design have increased the recommended intervals between oil changes, and on a newer vehicle, your best bet is to follow the manufacturer’s suggested maintenance schedule in your owner’s manual. (There might also be an oil brand or grade recommendation, especially on high-performance models, so follow that as well.)
Most will also recommend that you change it more frequently if you operate the vehicle under “severe usage” conditions, which includes consistently driving the vehicle for only short distances when the engine can’t reach its ideal operating temperature. Be sure to change the oil filter each time you change the oil.
What about aftermarket oil additives?
What about aftermarket oil additives?
There are all kinds of them out there, promising everything from longer engine life to vastly improved fuel mileage. Some actually did help back in the days when oils were of poorer quality, but today, oils contain pretty much everything your engine needs, and additives primarily just lighten your wallet.
And any time the oil warning lights up on your dash, pull over as soon as it is safe to do so, and turn the engine off. Even if the dipstick shows that it has plenty of oil, it could indicate a failure of the oil pump, which means that the oil isn’t getting to the places where it’s needed.
And any time the oil warning lights up on your dash, pull over as soon as it is safe to do so, and turn the engine off. Even if the dipstick shows that it has plenty of oil, it could indicate a failure of the oil pump, which means that the oil isn’t getting to the places where it’s needed.
While there is a third possibility that the warning light is malfunctioning, it’s still a good idea to have the vehicle checked before you start it again, to avoid possible irreparable engine damage. Keeping an eye on that vital fluid can be the key to the longest possible engine life.
