Oil weight, or viscosity, refers to how thick the
oil is. The temperature requirements for oil set by
the Society of Automotive Engineers (SAE) is zero
degrees F (low) and 210 degrees F (high).
Oils meeting the SAE’s low-temperature
requirements have a “W” (which stands for
winter) after the viscosity rating (e.g., SAE
10W), and oils that meet the high-temperature ratings have no letter (e.g., SAE 30).
Multi-weight oils (such as SAE 10W- 30) are a
new invention made possible by adding polymers to oil. The polymers allow the oil to have
different weights at different temperatures.
The first number indicates the viscosity of the
oil at a cold temperature, while the second
number indicates the viscosity at operating
temperature. Engines need oil that is thin
enough for cold starts and thick enough
when the engine is hot.
The most popular motor oil weights and
viscosity grades are:
• SAE 5W- 30. Performs well in sub-zero
temperatures. A relatively thin motor oil
that provides excellent fuel economy and
low-temperature performance. Used
primarily in newer-model automobiles.
• SAE 10W- 30. Performs well in temperatures
above zero degrees F. A slightly thicker
version of 5W- 30 motor oil. Frequently
recommended for most automobile engines,
including high-performance multivalve and
• SAE 10W- 40. Performs well in temperatures
above zero degrees F. A thicker oil that
provides excellent viscosity. Works well for
controlling engine wear and preventing oil
breakdown from oxidation. This heavier-weight oil performs better in hotter climates
and is typically recommended in vehicles and
trucks with larger engines. Possibly a little too
thick for wintertime in some cold climates.
• SAE 20W- 50. Performs well in temperatures
above 20 degrees F. Maximum protection
for high-performance, high-rpm engines
because of its high viscosity. An excellent oil
for hot climates and towing at high speeds
for long periods of time.
When choosing oil, always follow the manufacturer’s recommendation for your vehicle.
How often should oil be changed?
If you change your oil and filter every 3,000 to 5,000 miles (or every three
months, whichever comes first) and check its level regularly, chances are
you’ll never experience an oil-related problem. For drivers using synthetic
oil, intervals as long as 5,000 miles or six months between changes are
Some service centers will tell you that extreme driving conditions,
such as stop-and-go traffic or extremely cold weather, require more frequent
changes. The truth is that every three months or 3,000 miles is pretty extreme. If you aren’t driving in stop-and-go traffic, through minus-20-degree
blizzards or up mountain passes with a 5,000-pound trailer, you could
FUEL INJECTOR CLEANER
TRAVELING THE OPEN ROAD can be enjoyable,
especially if your engine is in top form. But
clogged fuel injectors can adversely affect an
While all U.S. gasoline contains additives, some
gasoline can cause performance problems
related to deposits in the fuel intake system.
If your car hesitates or stumbles during
acceleration or experiences loss of power, a
clogged fuel injector may be the culprit. These
deposits can also lead to reduced fuel economy and increased emission of hydrocarbons
and carbon monoxide.
A bottle of fuel injector cleaner added to a
tankful of gasoline can help restore clogged
fuel injectors to like-new cleanliness in one
tankful, while you drive. In addition to removing deposits and helping to restore lost power
and performance, fuel injector cleaner contains
an inhibitor to protect the fuel system from
rust and corrosion and helps remove water to
fight gas-line freezing.
Look for a fuel injector cleaner that will not
contribute to combustion chamber deposit-related engine knock, ping and run-on; is safe
for catalytic converters and oxygen sensors;
can be used with oxygenated fuels; and
contains no alcohol.
Pour the entire contents of a bottle of fuel
injector cleaner into a nearly empty fuel tank.
Then refuel with up to 16 gallons of gasoline.
Fuel injector cleaner is safe for use every
1,000 miles or as needed to keep fuel
injectors clean. A