First
it was pumping our own gas, next it was checking our own oil. Now women are browsing
automotive departments for brands and types of motor oil. In fact, in households
that fix their own cars, one-third of the mechanics are women, according to the
Automotive Aftermarket Industry Association.
As
with most do-it-yourself projects, materials are important. Like shopping for
food and medicine, it helps to know how to read the label. The Society of Automotive
Engineers (SAE) and the American Petroleum Institute (API) have established several
classifications that defines the characteristics of engine oil. These are shown
in the donut shaped logo on the oil container label.
Performance
Ratings
The API classification is a two-letter code that defines
the oil performance characteristics under different engine speeds and loads, as
well as temperature. The letter “S” is for gasoline powered engines
and the letter “C” is for diesel powered engines. The second letter
indicates the application. Only SL, designated for all automotive engines and
SJ, for 2001 and older engines, currently are used.
Viscosity
The
SAE classification indicates the oil viscosity and is referenced by a number that
appears in the center of the donut shaped logo. The higher the number, the thicker
the oil. Thick oil has a high resistance to flow, which means a high viscosity.
Oil classified with a “W,” like 5W or 10W for example, indicate the
viscosity rating applies at subfreezing temperatures and are generally used for
winter conditions. A number rating without the “W” means that the viscosity
rating applies at 212°F.
The
problem with single grade oil is that the W oils tend to thin out too much in
warmer weather and the non-W numbers tend to thicken too much in colder weather.
Single grade oils are generally meant for one temperature only and require an
oil change with each change of season. That is why most vehicles today call for
a multi-grade oil like 5W-30 or 10W-40. These oils have suitable flow properties
at both ends of the temperature spectrum, no matter what the season.
Fuel
Economy Rating
The third part of the label classification is the
“Energy Conservation” term. Oils are rated on their ability to reduce
the amount of fuel consumed during driving. Those that are at least 1.5% better
than a standard reference oil are rated as Energy Conserving. If the oil is at
least 2.7% better, it will be labeled as Energy Conserving II. Oils with this
classification are designed to reduce internal engine friction and improve fuel
economy.
Synthetic
Oils
There are many synthetic oils on the market today and a lot
of advertising to promote them. They tend to wear longer and may perform better
in extreme conditions. They are also slightly more expensive. Using synthetic
oil certainly isn’t harmful, but it may not provide any significant benefit.
Follow
the vehicle manufacturer’s recommendations. Change your oil according to
the maintenance schedule and always replace the filter when changing oil. |
