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Synthetic is generally regarded as superior, but conventional costs less. When does it make a difference to your car?
- Conventional oil is still a big favorite
- Synthetics are catching on more as time passes
- Conventional oils deliver lower price points and greater availability
- Synthetics can offer greater performance and longer life
Every vehicle owner knows how important oil changes are to maintain a healthy and efficient engine. Taking an extra step and changing the type of motor oil that goes into your engine takes a little more thought.
Both conventional and synthetic oils have their fans, but there are certain circumstances where a switch may be the right decision — and don’t believe the myth that you can’t successfully change back and forth if your vehicle’s condition allows. Let’s explore the pros and cons of these two types of motor oil and how they might relate to you and your vehicle.
Conventional oil and its advantages
Conventional oil (also known as mineral oil) is derived from refined crude and is still a hugely popular choice for engines. Its basis as a fossil fuel means there’s plenty of it around, making it cheaper than alternatives, and its history of reliable performance means it has public faith on its side.
Of the two types of motor oil, conventional is the better choice for many older or more worn-out engines. This is because conventional flows less smoothly than synthetic, which is actually an advantage as it reduces the odds of gear grinding. The slower an oil flows, the more time it spends lubricating parts and that’s a big plus for older engines.
Brand new cars can also benefit from using conventional oil because manufacturers sometimes use their own brand of it when putting the vehicle together (typically referred to as a break-in oil). If this was the case with your model, sticking with conventional for at least a while after purchase means the new engine gets to keep running on what it was first lubricated with.
Disadvantages of conventional oil
Conventional oil is more prone to degradation via oxidation, creating common engine hazards like extreme heat, corrosion, sludge deposits, and particulate matter. Conventional oils also don’t do well in cold conditions, where they can start to thicken up, reducing their effectiveness by making them harder to circulate.
There is also the environmental impact of conventional oil, which can be highly toxic, posing a threat to people, wildlife, and whole ecosystems through smoke pollution and runoff into water bodies. Then there’s the big picture disadvantage: Sooner or later, conventional oil reserves will be fully depleted. Some project this scenario as coming true in this century, others say it’s a long way off.
The harder conventional oil becomes to find and extract, the more the price will have to go up and the likelier it is that demand for it will drop (and there are signs that’s already happening). This brings us to conventional oil’s biggest competitor.
Synthetic oil and its advantages
Synthetic oil isn’t new on the block; it’s had since 1929 to establish itself. Some varieties are drawn from base oils that are themselves drawn from crude oils. Other types are purely man-made. Manufacturers are typically cagey about revealing their precise process, but the basic rule is that synthetics come from breaking down and artificially restructuring petroleum molecules for a precision result intended for a particular application.
One thing we can see clearly is that synthetics have greater chemical stability and a higher viscosity index than conventional oil, making them longer lasting and better performing at high and low temperatures. Synthetics may be perfect for certain high-performance vehicles to achieve maximum performance, making it a less attractive option for the casual driver of a standard vehicle who never needs to push their ride to the limit.
Synthetics are longer lasting than conventional and less harmful to the environment due to less of the synthetic oil being lost to the vehicle’s exhaust stream. Synthetic oil also leaves fewer deposits in the engine, which makes for a cleaner engine with a longer lifespan and performance. They also move faster around the engine; a plus wherever turbochargers are present.
As with all types of motor oil, the best time for a synthetic oil change is whenever the manufacturer’s manual recommends. Don’t get caught up in myths and rules of thumb that cite figures like 3,000, 5,000, or more miles.
Disadvantages of synthetic oil
The most common complaint with synthetic oil is the higher price since synthesizing oil is more costly than drawing it from petroleum. Whether that can be definitively classed as a disadvantage really depends on how much you’re willing to spend. There is a middle ground in synthetic blends, which offer performance perks over conventional oil but aren’t as expensive as full synthetic.
Other concrete disadvantages include lower fuel economy at highway speeds and a tendency for synthetic additives to separate when in cold storage. Synthetics can also be harmful to older engines, particularly rotary engines, where it may negatively impact the apex seals. Nor are synthetics well-suited for breaking in new engines, which can benefit from a little friction to smooth out rough spots.
Some older engines may also rely on lead in their oil, and that’s an impossibility with synthetics because they don’t hold lead in their suspension. Synthetics are also harder to dispose of, making it essential to let any mechanic you visit know that you use it, or know how to dispose of it by yourself.
Make all the right choices with Mercury Auto Transport
Whichever oil gets your vote, an oil change will put your car in better shape before car transport. Mechanics can check everything’s in good health and locate and repair any leaks that could prove costly should your vehicle start dripping onto others while in transit.
Mercury Auto Transport offers more vehicle-related information and shipping insight via our auto transport blog. As a full-service car shipping broker specializing in connecting carriers with customers all across the country, we can help make the process reliable and transparent. You can contact us to ask any questions or get a vehicle shipping quote in minutes.