Most drivers know that motors need
oil, but for many the understanding stops
there. Here are some things you should know
for a better appreciation.
Let the car sit for at least five minutes before
checking, to give the oil time to settle into the
sump, or reservoir, at the bottom of the engine.
with the hood open and securely
propped, locate the dipstick. its location var-
ies, but you can find it by looking for a brightly
colored handle—yellow, red or some other
remove it and wipe it with a clean rag or
towel. reinsert it into the hole, then slowly
remove it again. Check the level. the oil mark
should fall between the two hash marks on the
dipstick. if it’s below the lower level, you need
to add oil. Before you do so, though, wipe the
dipstick again and check it a second time.
still low? Add a quart and recheck it. (it’s
best to add the oil, then start the engine to
circulate it, then let it sit for another five min-
utes before rechecking.) if it’s still below the
lower hash mark, you may need to add
another quart, but be careful not to overfill it,
as this can lead to other problems.
How to check your oil
Checking your oil level is a fairly simple
procedure. experts generally agree that it’s
best to drive the car first before checking it. so
take a little spin, then find a cool, shady spot
to pop the hood.
intervals as long as 5,000 miles or six months
between changes are considered acceptable.
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 probably go
longer between changes, and there’s certainly
almost no condition that would warrant even
more frequent changes.
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,
The Costco Connection
You can find most everything you’ll
need to hydrate your car, including windshield wiper fluid, antifreeze and a selection of motor oil, at your local Costco
warehouse and on Costco.com.
If you own or are looking to own an RV
or boat, check out the article on page 51,
which details an RV and boat purchasing
and refinancing service for Costco members.
Deciphering oil weight
oil weight, or viscosity, refers to how
thick the oil is. the temperature require-
ments for oil set by the society of Automotive
engineers (sAe) is 0 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 subzero temperatures. A relatively thin motor oil that
provides excellent fuel economy. Used primarily in newer-model automobiles.
• SAE 10W- 30. Performs well in temperatures above 0 degrees F. A slightly thicker
version of 5w- 30 motor oil. Frequently
recommended for most automobile
engines, including high-performance multivalve and turbo-charged engines.
• SAE 10W- 40. Performs well in temperatures above 0 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
• SAE 20W- 40. 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
Reprinted from the 2008 Costco Household
Almanac online at Costco.com; click on “Costco
Connection Magazine,” then “Almanac.”