Engine Oil Myths & Facts

Many car owners may not be aware of engine problems that can occur from using poor quality oil. This is mainly due to some common misconceptions about engine oil. Our goal with this page is to dispel some of these engine oil misconceptions.

Myth: I think the engine oil I'm using is good enough because I haven't had any problem with my engine. So there's no need for me to pay extra money for higher quality engine oil

Fact: You may or may not be able to see the impact of inferior quality oils right away. In a seemingly good performing engine, harmful contaminants may already have entered the engine's lubricating system and begun to cause corrosion, rust, wear, etc. Just because you haven't experienced any symptoms doesn't mean problems don't exist. When problems do become visible, it may be to late or very costly to bring the engine's performance back to normal. It's always advisable to stick to high quality, warranty backed brand for maximum protection.

Myth: Older vehicles have already passed the manufacturer’s warranty period. There is no need to use quality oil.

Fact: Older engines are more prone to wear and tear. An older engine needs quality lubrication to help protect crucial engine parts and ensure long-life.

Myth: Good quality oil will leak from the seals of older vehicles.

Fact: Good quality oil does not cause leaks. In fact, good quality oil is tested in dozens of industry standard, OEM-approved tests to prove its seal performance. Oils are tested to ensure that they are fully compatible with the electrometric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, good quality oil provides the same advantages as when used in a new engine.

Myth: Synthetic engine oil is only for new engines or vehicles.

Fact: Quality synthetic engine oil can be used in old as well as new cars including vehicles in which conventional oil was previously used. Synthetic engine oils are beneficial for the good health, long life and top performance of new or old cars.

Myth: Engine oils can cause sludge.

Fact: This is true. Poor quality oils can contribute to sludge build-up. Sludge deposits are formed by a combination of dirt, soot, partially burned fuel, oxidised motor oil, leaked coolant and condensed water vapour produced during combustion. Good-quality motor oil keeps these contaminants separated and held in suspension. They are drained with the oil and not left behind to create deposits or sludge. Using a good quality oil along with regular oil and filter changes will prevent sludge problems from occurring.

Myth: The normal oil change intervals recommended by the OEMs are conservative. It’s safe to extend the time between oil changes.

Fact: The normal oil change intervals provided in the owner’s manual are not conservative. Engines have become more demanding of an oil, but recommended oil change intervals have not been shortened. According to the definitions in the owner’s manuals, most of us drive vehicles in “severe” service conditions. The oil change intervals these demanding conditions are about half as long as normal intervals. Stop-and-go, short-trip, inner city driving creates very tough conditions for an engine oil. We advise against extending any OEM engine oil drain interval recommendations for any type of service.

Myth: You can tell the condition of an oil by its look, smell and color. If it turns dark or goes black quickly, it’s not good.

Fact: Nothing could be further from the truth. If an oil is doing its job cleaning the engine, then it will be dirty when it is drained. In the case of diesel engines, the oil may look dirty within a few hours of operation. This indicates that the motor oil is keeping soot, dirt and other combustion contaminants in suspension. These will then be carried to the filter or removed from the crankcase when the oil and filter are changed. Good quality motor oils are formulated to hold these contaminants in suspension until the oil is drained when the oil and filter are changed.

Myth: New or rebuilt engines need to be “broken in” with non-detergent, non-synthetic oil.

Fact: With the technologies used in today’s oil formulations and engine designs, manufacturers no longer recommend the use of non-detergent oils for the break-in period. In fact, engines come factory-filled with high-quality performance motor oil which contains high levels of detergents and dispersant additives.

Myth: Thicker motor oil is better for your engine and increases engine life.

Fact: The main reason vehicle manufacturers recommend thinner or lighter viscosity grades of engine oil is because a gain in fuel economy may be achieved. Lower viscosity oils may help reduce internal engine friction. As a result, it takes less energy to pump the thinner oil throughout the small passages inside an engine.

Thinner motor oil is also essential for easy starting, particularly in cold weather and for good lubrication once the engine starts. Thinner oils, such as SAE 5W-30, will flow faster than heavier motor oils during start-up and initial engine operation helping to protect the engine. The viscosity grade(s) recommended by the vehicle manufacturer depend somewhat on engine design. Engine manufacturers have spent considerable time and expense experimenting with different viscosity grades. The owner’s manual indicates the grades they feel will best protect the engine at specific temperatures.

While one manufacturer’s engine may require an SAE 10W-40, another manufacturer’s engine may require a SAE 5W-30 viscosity grade. This is likely due to different tolerances within the engine, field test experience or other engine design factors.

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