The importance of oil
Oil keeps everything lubricated, cool and clean — which is why it gets dirty.
When you start your car, oil begins lubricating your engine. Numerous additives within the oil help it cool and reduce friction between internal moving parts. Oil also cleans away dirt and contaminants, preventing premature engine wear.
For example, for every gallon of fuel that is consumed, about one gallon of water is generated. Most of this water turns to steam and exits through the exhaust (which you may notice on cold mornings when that water actually drips from the tailpipe). But some of this moisture does get into the dead air space of your engine. There, it mixes with other chemicals and forms sulphuric and nitric acid. Dirt and residual fuel will also find their way into this dead air space. The oil must continually keep this area clean so it sweeps away the dirt and absorbs the acids and fuel.
As a result of all the dirt and contaminants it picks up, oil needs to be changed regularly. Also, when oil becomes too old and dirty, you're no longer getting the full benefit of the additives it contains. The oil becomes less effective at cooling and lubricating your engine. What's worse, the increased friction and chemical build-up in used oil can deteriorate your engine's moving parts.
You see those cryptic combinations of letters and numbers on oil containers everywhere. So what do they mean?
To indicate viscosity, the SAE (Society of Automotive Engineers) developed a standard scale.
To decipher them, you have to understand viscosity.
Viscosity measures the oils ability to flow. In other words, if you tip an oil bottle over, how fast it spills out indicates its viscosity.
The more viscous it is, the slower it moves, for example:
("W" stands for winter)
• 0W is thinnest
• 60 is thickest.
This means the viscosity is at 10W when the engine is cold and 30 when the engine is hot.
Low viscosities are good for cold temperatures (hence the "W" association!) because the oil is thinner. Thinner oil flows more easily and moves quickly. When you start a cold engine up again, oil needs to travel to the top of the engine, where it trickles back down. Since oil is vital to lubricating your engine, it needs to move quickly and low viscosity helps it do just that.
But when your engine heats up, higher viscosities mean the oil won't thin out too much and will keep parts separated by a film of oil.
So your oil is always maintaining a delicate balance: it needs to flow well when the engine is cold but also retain enough body at higher temperatures to keep metal parts lubricated and separated. To find out what oil grade is right for your car, check your owner's manual.
You see the word every time you visit the fuel station but what does it mean?
Octane ratings are a measure of the fuel's ability to resist engine knock. Engine knock is caused by fuel being ignited by something other than the spark plug.
If you are using an octane grade that is too low for your car, something other than the spark plug can ignite the fuel in the engine. The engine could even get hot enough where the fuel explodes by itself.
What octane does your car need?
Check your owner's manual. Don't upgrade to more expensive octane ratings unless your manufacturer recommends it.
Most cars today use an on-board computer to monitor and manage several of your car's operating systems. These on-board computers have more memory capacity than the first space craft that went to the moon.
If this computer detects irregularities in your car's operating systems, it will often turn on a dashboard warning light. Using a specialised scanner, a technician can read a trouble code off the computer that details what went wrong.
After 1996, most trouble codes were standardised across manufacturers. So now all cars use five character codes to report problems. The computer can even remember intermittent problems that have returned to normal.
Dashboard warning lights come on if something substantial has occurred. Less serious problems are still detected and stored for analysis by a technician. Early detection of these problems can reduce repair costs and prevent breakdowns.
Under- or over-inflation of tyres can cause:
• Uneven tread wear
• Weaken your tyres
• Reduce traction
• Impact fuel consumption
• Increase wear
Eventually, you could have an inconvenient flat tyre or even a dangerous blowout. Over-inflation means the weight of your car is not distributed evenly across the entire tread but is instead concentrated on a thin strip in the centre. Under-inflation means the tyre is soft and the outside edges work harder than the softer centre. The extra rolling resistance makes your car work harder to move and increases fuel consumption.
Be sure to check your tyre pressures regularly, and maintain the recommended pressure listed in your owner's manual. Also, you can usually find this recommended pressure on a sticker posted on the door pillar or in the glovebox.
Each of your tyres will wear differently due to its position and the type of car you own.
So tyres wear evenly, remember to balance and rotate your tyres according to manufacturer's recommendations. Check tread wear, using a depth gauge or seek professional advice.
Improve your fuel consumption
1. Choose the right octane.
If you are using an octane grade that is too low for your car, something other than the spark plug can ignite the fuel in the engine. If your car detects abnormal ignitions, its on-board computers will slow down the car's timing so severe damage does not occur. This slowing down means you are no longer getting optimum engine performance or miles per gallon.
Check your owner's manual to learn about the correct octane for your car. Don't upgrade to more expensive octane ratings unless your manufacturer recommends it.
2. Keep tyres inflated to correct levels.
Under-inflation means the tyre is soft and the outside edges work harder than the softer centre. The extra rolling resistance makes your car work harder to move and it reduces fuel efficiency.
Be sure to check your tyre pressures regularly, and maintain the recommended pressure listed in your owner's manual. Also, you can sometimes find this recommended pressure on a sticker posted in the car, on the door pillar or in the glovebox.
3. Don't drive at high speeds.
Driving at 65 mph as opposed to 55mph increases fuel consumption by up to 20%.
4. Change your air filter.
This is important because air is just as crucial as fuel in the combustion process that powers the engine. Air is drawn through the air filter, then the air intake manifold and into the cylinders. There, it mixes with fuel to create the small explosions that power your car.
A dirty air filter prevents the cylinders from drawing in enough air, and affects the air/fuel mixture. This can result in poor fuel economy.
5. Have your fuel system professionally cleaned.
Dirt, sand and other impurities can clog your fuel filter and starve your fuel injectors. Starved or clogged fuel injectors can impede engine performance and reduce fuel efficiency.
When to change your oil
To keep your oil clean and your engine healthy, a good rule of thumb is to change your oil and filter every 6 months or 6,000 miles.
Also check your oil level with the dipstick every month. Check the condition of the oil as well. Brand new oil is light amber and relatively clear. After a few minutes of use, however, it becomes much darker.
If the oil looks extremely dark or grimy, it may be time for a change. Check your oil for:
• Bubbles or foam
• A milky appearance
• A strong smell of fuel
These signs could mean you have water or fuel contamination and this could result in a high oil level. Consult your local garage for investigation of cause.
Your engine runs on a delicate balance of fuel and air. Dirt, sand and other impurities can clog your fuel filter and starve your fuel injectors.
Starved or clogged fuel injectors can impede engine performance and reduce fuel efficiency.
Warning signs of a clogged fuel injector or fuel filter include:
• Stalling while driving.
• Misfiring or hesitation during acceleration.
• Difficulty starting or long cranking periods.
If you find your temperature gauge creeping into the red, turn on your heater. Sound crazy? It can work.
Your heater pulls heat from the liquid that cools your engine. If you turn on the heater and set the fan to full, your heater will pull more heat from this liquid, helping it to cool the engine.
Also, be sure to turn off the A/C at the first signs of overheating. Doing so will take a load off your engine.
The best thing you can do, however, when your engine overheats is to pull over as safely and quickly as possible and wait for your car to cool down. Never attempt to remove the radiator cap until the engine has cooled, the coolant is boiling, and under pressure.