Is 5W 30 synthetic oil

The difference between mineral oil and synthetic oil

Table of Contents

Overview: synthetic oil vs. mineral oil

The most important differences between mineral oil and synthetic oil for motor oil buyers simply explained.

Differences in manufacturing

  • mineral oil is obtained from a more or less contaminated starting product (crude oil) through refining. Ideally, the manufacturer manages to sort out the “bad” components of the oil and, if possible, only leave similar molecules.
  • Synthetic oil is a designed or synthesized product: The oil manufacturers “assemble” molecular chains that have the desired properties.
    It's best to imagine it like building with Lego bricks: With synthetic oil, the engineer can assemble the ideal shape from a wide variety of small bricks. When it comes to mineral oil, someone has put stones together before him and he has to be content with choosing from these clumps the ones that suit him best. He can take it apart, but he doesn't have the full range of options.


Different properties:

  • Mineral oil is significantly cheaper to produce than synthetic oil, and that is reflected in the price.
  • Real synthetic oil has a better flow behavior even at low temperatures in winter, so that the engine is supplied with engine oil faster and better during a cold start and is thus less stressed.
  • Real synthetic oil is more temperature stable. This means that the oil film, which is important for lubrication, does not become too "thin" or even tear at high temperatures (high speed range, full load).
  • The advantages in terms of flow behavior and temperature stability that synthetic oils already have, must be achieved with mineral oil by adding additives, the effect of which can deteriorate over the course of (operating) time.

Fully synthetic & semi-synthetic motor oil

The motor oil manufacturers have of course understood that many buyers associate the term “synthetic” with higher quality and willingness to pay and are making use of this in their advertising. For the buyer there is now an almost inscrutable jumble of terms on the oil packaging: "HC synthesis", "Synt", "SHC synthesis", "synthesis technology", etc.

The problem with that: The term "synthesis" or "synthetic" is not protected. The oil manufacturers Mobil (now ExxonMobil) and Castrol have even quarreled about it in the USA. Mobil was of the opinion that Castrol should not call its Syntec brand a synthetic oil, as it was a highly refined and chemically modified one, but still a mineral oil and not a real synthetic oil. In the end, Castrol was allowed to call it synthetic and since then the term has been used very "creatively" by many manufacturers.

Many engine oils, which are predominantly made from Group III base oils (mostly through Hydrocracking refined mineral oil) are called synthetic or semi-synthetic. They are either very highly refined and / or contain a proportion of fully synthetic Group IV (PAO) oil.
Read here what base oils actually are and why they play a major role in the quality of the engine oil.

At least the term "fully synthetic“So it still offers a chance for orientation. Fully synthetic engine oils should consist of at least 80% Group IV base oils (PAO). Typical viscosities for fully synthetic engine oils are SAE 0W-30 and 5W-40.

A critical note at the end:
As an observer of the motor oil market for end customers, one can easily get the impression that some motor oil manufacturers - even though they have fully synthetic as well as partially synthetic or HC motor oils in their range - do not want to explicitly tell the customer whether it is full or partial synthesis. There is only a reference to “synthesis” on the packaging. Do you hope that the good reputation of the manufacturer's fully synthetic oils will also be reflected in the other products (which don't have to be bad)?
In addition, some products or product lines that were previously based on fully synthetic base oils are being converted to Group III oils without much ado - while retaining the brand name, which is often no longer understandable for the consumer. And it seems like marketing and transparency aren't such good friends when it comes to motor oil. A rogue who thinks badly.



Categories Auto KnowledgeTags Motor Oil, Synthetic Oil