Motor oils recently examined by the Petroleum Quality Institute of America include three brands of SAE 5W-30 grades (Circle K, Quantum X-5, RPMaximum) and XCEL SAE 10W-40.
The XCEL product tested raised eyebrows. And the reason it does is because the label on the XCEL product claims that this is a multigrade 10W-40 motor oil meeting an American Petroleum Institute (API) SA Service Classification. Plain and simple, this can’t be.
By definition, API SA motor oil cannot be a multi-viscosity grade product. API SA motor oils are “straight mineral oil.” As such, they contain no additives. Multigrade motor oil requires the use of viscosity modifier additives.
In addition, the XCEL “PREMIUM” SAE 10W-40 product tested is labeled as meeting API SA which is an obsolete Service Classification. As noted on the back label, this motor oil “Contains no additives. It is not suitable for use in most gasoline powered automotive engines built after 1930. Use in modern engines may cause unsatisfactory engine performance or equipment harm.” At the same time, the back label states “This economical quality blended lubricant provides excellent and durable lubrication for automobile and truck engines to minimize oil consumption cost.” This claim is inconsistent with the API SA Service Classification.
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| Circle K | Quantum X-5 | RPMaximum | XCEL |
