The short answer: It depends. It can be as good as, better than, or not as good as virgin product. It depends on a number of issues, from how the base oil and/or finished products are made to how you define whats good and who its good for. And the same can be said of virgin products.

A lubricant blender, for example, may favor using some rerefined API Group II base oil over virgin because it offers cost advantages. Besides the possibility of a lower acquisition cost, some rerefined base oils have lower volatility and higher, more consistent viscosity indices than virgin, and therefore require less trim stock (i.e. Group III) in a motor oil blend. Others counter that some virgin base oils have a slight advantage in the area of saturates, which could translate to improved performance in oxidation tests. Whereas there is still debate about the latter, most agree that the cost/performance advantage of either type depends on the specific base oil, the producers quality controls, and the additives used to blend finished products.

Supply can also be an important consideration for blenders. Even if rerefined offers a cost advantage, its not as good as virgin if you cant consistently secure volumes, or if there is variation in quality from the same supplier due to shifts in feedstock and processing. Again, the same must be said about virgin base oil.

Another consideration is the blenders ability to sell rerefined motor oil. Green is not as good as virgin if the blender doesnt have the skill set to sell it. For those who do, rerefined can be better than some virgin products.

This may be why marketers offer a mixed bag of opinions as to whether rerefined motor oil is as good as virgin. When good is defined by performance, they generally say the data is there to support claims that rerefined is as good. But, they are quick to add, it depends on the products compared.

A fair comparison is one that looks at same-tier motor oils, i.e., ones meeting the same viscosity grade and API service classification. Because you can be fairly certain that a top-tier, full synthetic will outperform a lower-tier, rerefined motor oil. Similarly, a premium-brand conventional motor oil will likely offer performance advantages over some rerefined competitors. In part, this is because there are inherent differences among blenders. Whether it is rerefined or virgin product, some blenders do better than others in their manufacturing practices, choice of additive packages, quality targets and other factors.

Rerefined also can be as good as or better than virgin based motor oil if the marketer knows how to sell it. This is because rerefined provides a real and meaningful opportunity to differentiate a product based on its green value. And although consumers may not currently be willing to pay much (if any) premium for green motor oil, an increasing number select it when given a price-neutral choice. In addition, some fleets favor rerefined lubricants because they complement a green corporate strategy.

Government regulations can also make rerefined as good if not better than virgin based products. Current federal and state guidelines favor the purchase of rerefined lubricants, and future regulations are expected to increase this preference.

So is motor oil made from rerefined base oil as good as virgin motor oil? Once again, it depends. This answer would hold true when asking about any motor oil in the market, rerefined or not; some are better than others, for many reasons. With that said, the good could go either way.

At the end of the day, rerefined motor oils have come a long way in terms of quality. Most meet the same specifications as virgin products and have OEM approvals. In addition, rerefined base oils are undeniably green when used in most applications. And as they move away from past perceptions, consumers may find the green of rerefined motor oil to be better than the black of crude-derived products.