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The Ins and Outs of Motor Oil

Among the most bang for your buck you’ll get when making any sort of repairs or maintenance to your car is when you add a quart or a litre of motor oil to the engine.

The Role of Vehicle Lubricants

Modern engines, transmissions, and differentials require modern lubricants to keep them healthy. Think of motor oils, transmission fluids, and gear oils as the lifeblood of your vehicle.

As the mechanical technology in motor vehicles has increased, so has the need for oils engineered to perform in these technological marvels. That’s why choosing the correct motor oil will keep an engine working properly for many years.

And why’s that? Well, let’s take a look at the benefits.

How Motor Oil Benefits Your Car

For starters, the motor oil will protect your engine against frictional wear. It will also neutralise acid build up, as internal combustion naturally produces sulfuric acid. If that’s not enough, motor oil also suppresses corrosion and helps cool the power-plant.

The additive package in motor oils also contains dispersants, detergents, anti-wear agents, viscosity modifiers, anti-foaming agents, and pour-point depressants. The latter will allow the oil to pour at very cold temperatures.

Choosing the Correct Lubricants

Lubricant specifications and performance parameters are enumerated by: the Society of Automotive Engineers (SAE), who established the viscosity requirements; the American Petroleum Institute (API) and the International Standardisation and Advisory Committee (ISAC), who established the service classifications.

There is also the Association des Constructeurs European d’Automobiles, which parallels the standards established by the API and ISAC, but mainly for engines of European manufacture.

Don’t be confused by all the initials and oil classifications. Every time there are improvements made to engines, there are also improvements made in the lubricants that protect them.

Current motor oil service classifications will protect all current and previous year model vehicles. There are separate classifications for spark and compression ignition engines; gasoline or diesel fuelled, but most oils are classified as multiple-use, and are appropriate for either type of engine.

What to Look Out For

The most important measure, viscosity is the measurement of the internal resistance to flow of any fluid; the higher the viscosity number, the greater the resistance to flow.

For warm weather motoring, motor oils with a 30 or 40 viscosity rating are selected. For cold weather driving, the viscosity rating should be 10 or 20. The advent of multiple viscosity oil has precluded the need to change the oil in the event of a drastic temperature change.

What that means is that a motor oil with a viscosity rating of 10-30 can operate at low temperatures as a 10 viscosity, and when the engine is warmed up and operating at higher temperatures, the oil performs as a 30 viscosity.

Another measurement of a motor oil is the Total Base Number (TBN). Oils are formulated with an alkaline reserve to neutralise acids. When the TBN has dropped to half the original number, the oil should be changed. This usually coincides with depletion of the other additives.

Ultimately, don’t forget, the type of use the vehicle gets determines when the oil should be changed. If you often drive in peak hour traffic, where there is regular stop-start driving, the oil is likely to need change sooner. On the other hand, long travels on the freeway should extend the service interval. But as with anything related to your car, a bit of proactive maintenance won’t set you back either.