Most misconceptions regarding engine oil rest on corrupted traditions or overall lack of knowledge and using them may result in over-maintaining or damaging the engine. Adherence to engine oil myths rather than evidence-based guidance may add more to the maintenance cost and eliminate engine reliability.
These false impressions have lead to actual difficulties on more than one occasion in my decades of experience with engines of all manner and kind, both the average passenger automobile and the heavy-duty fleet. The propaganda is quite easy to misleading by inheriting old expressions that were developed in the previous generational generations, simplified opinions of good friends or incompatibility of the new engine machines with the regulations of the world 30 or 40 years ago.
Here, we are going to consider the most long-standing myths in and around common engine oil, why they remain unchallenged, and how they may be changed to operate with more sensible, factual information. As a vehicle owner who is attempting to prevent the bad habits you will avoid, a technician who is educating the customer on the topic, or a fleet operator that strives to make sure that their engine performs well, the knowledge of what the truth behind engine oil myths is will make you take better care of your engine.
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Why Engine Oil Myths Persist
The engine oil myths are not going away easily since they are usually begun with a mote of truth of the older technology or certain circumstances.
Habits of the past are a factor of great importance – what was good in the carbureted engine of the 1980s may not always be suitable in the turbocharged, direct-injection engine with stricter tolerances and electronics of the present day. Simplified guidance, such as, change every 3000 miles regardless of the conditions, is propagated because it is easy to memorize despite the fact that the current Gospel of oil changes defies a better formula and road circumstances.
It also does not fit well naturally: current engines run better on better oils since they are hotter, cleaner, and longer, yet most individuals still obey regulations that were in place when the engines could easily break down. All these contribute to the fact that old ideas are around and at times, this can result to over-maintenance and in the worst case scenario, lack of care.
Myth #1 — Synthetic and Mineral Oils Are Essentially the Same
The first thing to believe is that synthetic and mineral (conventional) oil are more or less the same oils because they all lubricate engines however this myth about synthetic oil does not take into account the basic differences that can influence performance and life cycle.
Synthetic oils are manufactured using chemically designed molecules and are more stable, they have better flow at low temperature and have higher oxidation and heat resistance. Refined oils, such as mineral oils, contain more irregular molecules and impurities that result in high rates of degradation, extensive levels of sludge in the demanding conditions, and decreases warmth in cold startup or high load working.
The myth continues in that the early synthetics were costly and not necessarily needed with the basic driving, and that some of the older engines operated well with conventional. However, nowadays, an increased number of manufacturers can suggest imposing synthetics as an ideal working condition and warranty. To see more closely the differences, check our detailed synthetic engine oil vs mineral oil comparison.
Myth #2 — Unused Engine Oil Never Expires
The unopened engine oil can last for an extended period in the bottle, but it is not true and people neglect the oil sitting in the bottle, and the neglect results in poor performance.
With time, even when in closed containers, the additives might deteriorate, they might oxidise (particularly due to temperature changes) and slow moisture may creep in. The average life of conventional oils is of an average of 5 years when stored under ideal conditions and synthetics have a life span of 7-8 years in ideal conditions. Containers that are open deteriorate with exposure to air.
The myth is based on the stability of the modern oils in relation to the older ones. Storage (cool, dry, stable conditions) is helpful though it is always necessary to examine production dates and never use very old stocks without checking anything.. Learn more in our guide to unopened engine oil shelf life.
Myth #3 — Oil Should Always Be Changed at Fixed Mileage Intervals
The old every 3,000 miles rule is reassuring, but assuming that fixed mileage is in itself absolute is one of the most widespread engine oil myths, that simplifies the real-life factors of determining oil life.
Neutral modern oils and synthetics, in particular, have extreme durability, typical of 5,00010,000 miles or longer, based on the vehicle. Fixed schedule does not consider such important aspects as extreme driving (short routes, towing, extreme heat/cold), oil quality, and engine architecture. The newer cars have many oil life monitors and are more accurate in timing by basing it on real-life conditions like temperature and load, and run time.
Using the miles only might result in wastage of early alternatives or dangerous extensions. Refer to your owner manual, observe and look at symptoms. See our related article on engine oil misconceptions for practical indicators.
Myth #4 — Dark or Black Oil Means the Oil Has Failed
The first intuition one gets in pulling the dipstick and viewing the oil as being dark or black sparks panic off alerts, however this is a major misconception. Being dark oil does not necessarily imply failure.
The current oils have potent detergents and dispersants which clean the engine by floating the soot, combustion byproducts, and minute particles. This brings about normal darkening which mostly takes place within few hundred miles when the oil does the work. Black oil is natural in diesels particularly and is a sign of good cleaning and does not point to a failure.
The real problems can be viewed through only abnormal problems such as the presence of the milky color (coolant contamination) or excessive thickness. Sight is not sufficient, but depend upon mileage, time, and analysis. To learn more about this, read our explanation of synthetic oil myths.
Myth #5 — Oil Additives Are Just Marketing Gimmicks
Others consider that reasons provided by connatural oil additives are an unwarranted gimmick now that they are part of necessary chemistry.
Anti-wear agents, detergents, antioxidants as well as viscosity modifiers among others are incorporated into the oils to ensure that they do not oxidize, they do not cause friction, they clean deposits and they do not impair performance at various temperatures. These are not optional, and it is these that enable oils to pass the API and OEM test.
In some cases, aftermarket additives are useful on worn engines, although when used in an engine with good quality oil they tend to interfere with the well-balanced formula. However, the engineering package of the premium oils is the source of the true value, rather than extras. Dive deeper with our post on oil change myths.
Myth #6 — All Engine Oils on the Market Are Basically the Same
You are tempted to believe any oil that satisfies basic specifications is identical in effect making it reliably act in the same way – yet its quality, test and formulation range.
OEM-approved oils receive extensive testing of better than minimum API testing, and superior base stocks and additive package are used in specific engines. Low-cost or generic products can just cover the essentials but not by conditions of extremity, resulting in increased wear or deposition or both with time.
Successes are seen in actual results: enhanced security, extended runtime and hydraulic cleanliness. These nuances are beneficial to the distributors and users. Explore more in separating facts from myths about engine oil.
Where to Find Reliable Information About Engine Oil
The ultimate shield against myths is to consult reliable sources as opposed to the rumors in the forums or out-of-date advice.
Never assume that any other book can be used, there is always an exact OEM manual to your vehicle, with a set of specifications and timing, which is specific to your engine. Include technical data sheets of recognized manufacturers and official and certified sources such as API or lubrication specialists.
Do not use random generic tips. To see the views of the experts, see our common engine oil myths Q&A.
Conclusion — Understanding Oil Facts Leads to Better Engine Care
Breaking engine oil myths Ignoring the common myths about engine oils is only achievable by making informed decisions rather than familiar ones. When it comes to the proper selection of oil type, the observance of actual shelf life, modifying the addition to actual circumstances, recognizing changes in colour, using correct additives, appropriate choice of formulations then not only does your engine last longer and run cleaner, but this also results into costs that are lesser and less to maintain with time.
Ask questions to the old, consult your manual, and keep in touch: little rectification in learning results in large scale gains in loyalty. Continue researching on technical subjects to be on top of the engine care best practices.