A General Comparison Between Synthetic and Regular Oil
Research into synthetic motor oil began during World War II. Both
Germany and the United States sought better lubrication properties,
while Germany also desired to be less dependent on crude oil.
True synthetic oil has a formula based on non-mineral (or vegetable)
sources. The United States, however, allows ?Class III? synthetics to be
classified as true synthetics. These oils are mineral based but have
been modified with certain chemicals and manufacturing processes so they
resemble synthetic oil.
?Synthetic blends,? or semi-synthetic oils, are made of a blend of
mineral oil and not more than 30% synthetic oil, providing many of the
benefits of pure synthetics without the added cost.
Synthetic Oil Advantages
Some of the advantages of synthetic oil include less loss due to
evaporation; improved high and low viscosity performance; better
resistance to thermal breakdown, oxidation issues, and oil sludge
problems; improved stability; improved cold-start lubrication; and
better fuel economy in some engines.
Synthetic Oil Disadvantages
The main concern about synthetic oil has been with new cars.
Synthetic oil’s lower friction characteristics, in the past, have made
it unsuitable for the new car break-in period. However, improved
part-manufacturing techniques in the car industry have made this concern
nearly disappear. Other potential disadvantages include potential
decomposition issues, primarily in industrial applications; issues in
certain older pushrod racing engines which have roller lifters where the
lifters may not operate properly; and possibly certain plastics
cracking due to stress in the presence of synthetic oil.
A 1990′s study of 75 New York City taxi cabs primarily focusing on
stop-and-go driving, found no difference between the use of synthetic
versus traditional motor oil.