frequently Asked questions
What are the State
of North Carolina vehicle inspection requirements?
In the state of North Carolina, any registered motor
vehicle not over 35 years of age must be inspected annually
for mechanical safety as mandated by state procedures.
A valid North Carolina vehicle registration is required
before an inspection can be performed. Vehicles are
not allowed to operate on North Carolina roadways without
a valid inspection certificate.
A North Carolina vehicle safety inspection is required
within 10 days of receiving a North Carolina license
plate or by the last day of the month printed on the
inspection window sticker. If a vehicle fails the safety
inspection, it cannot be operated beyond the expiration
date on the current sticker.
In conjunction with the annual safety inspection, a
vehicle of model year 1996 and newer may be required
to undergo an emission inspection. Diesel-powered vehicles,
heavy-duty vehicles, RV motor homes, and motorcycles
are exempt from an emission test. The emission test
is performed through the on-board diagnostic system
of the vehicle. A malfunctioning “check engine
light” or a “check engine light” staying
on, will result in a failed emission inspection.
If an emission inspection is not performed on a vehicle
requiring such within 4 months of its current expiration,
the North Carolina DMV will subject the vehicle owner
to a civil penalty and will disallow registration renewal.
Vehicles with after market window tinting must pass
the 35 percent visible light requirement as set forth
by North Carolina regulations. This test must be performed
each year regardless of previous tests results. An additional
fee is charged for the window tint test.
What do the numbers mean on an oil container?
These numbers indicate oil’s viscosity. Viscosity
refers to how easily oil pours at a specified temperature.
Some familiar examples of viscosity are 0W20, 5W20,
5W30, 10W30, 10W40, 15W40 and 20W50. Thinner oils have
a water-like consistency and pour more easily at low
temperatures. Thicker oils pour less easily at low temperatures
and have a consistency more like honey. A thin oil is
good for easier cold weather starting, reduced friction
and improved fuel economy - although very slight in
an individual vehicle, while a thick oil is better for
maintaining film strength and oil pressure at high temperatures
The viscosity rating of motor oil is determined in
a laboratory. The lower a viscosity number, the thinner
the oil, and the higher the viscosity rating, the thicker
the oil. Most oils today are a multi-viscosity rating,
which provides benefits of both thin oil and thicker
Viscosity ratings for commonly used motor oils typically
range from 0 to 50. The “W” in the rating
indicates“winter” grade oil and represents
the oil’s viscosity at 0 degrees Fahrenheit. The
second number in the rating refers to multi-grade oil
and indicates the high temperature viscosity.
Why does engine oil need to be changed?
Actually oil does not “wear out” - in
fact, it can be recycled and reused again and again.
What does wear out - or get used up - is the additive
package that’s mixed into oil when it is manufactured
and bottled. Most modern motor oils are formulated from
various base stock oils, which include both conventional
and synthetic oils, and an additive package. The additives
include detergents, viscosity modifiers, friction modifiers,
seal additives, anti-oxidants, anti-wear agents, and
corrosion inhibitor and pour depressants and help keep
internal engine parts clean and free of sludge, carbon
deposits and varnish. Once these additives are used
up, there is no longer anything to keep the gunk at
bay. And while the oil itself is not used up, it eventually
maxes out its ability to hold contaminants and dirt
particles in suspension - away from moving parts. That
means increased friction and accelerated wear and tear
on engine components.
When should oil be changed?
This varies from vehicle to vehicle and driver to
driver. Most manufacturers recommend two scheduled maintenance
categories -”normal” and “severe”.
To be classified as “normal”, you should
drive your vehicle regularly at highway speeds for extended
periods of time, 20 - 30 minutes. Stop and go driving
should be kept to a minimum. Therefore, most drivers
fall into the “severe” driving style. These
habits include minimal highway driving with frequent
stop and go trips, full throttle starts with quick stops
and dusty driving environments. Also lightly used vehicles
that go out once or twice a week or sit for extended
periods of time are considered severe use. Condensation,
unburned fuel and other contaminates quickly foul the
oil, thus reducing its ability to protect against wear
Industry standards sets “severe” driving
oil and filter changes at 3 months or 3000 miles. “Normal”
changes can go 5000 - 6000 miles. The use of synthetic
oils can push change intervals to 7500 miles.
What does the “Check Engine” light mean?
Today’s newer vehicles are highly sophisticated
and designed to be less polluting and more fuel efficient.
All 1996 and newer cars and trucks have an advanced
computer control system that is designed to manage and
monitor the operation of the engine, transmission and
emission control components. This control system is
referred to as OBD II,
or on-board diagnostics, second generation.
The OBD, on-board diagnostic
system, constantly monitors and assesses the performance
of engine components, emission control components, engine
sensors and the vehicle’s computer itself, ready
to make any adjustments necessary or to communicate
any problems that may occur. These problems are referred
to as diagnostic trouble codes
(DTC’S), and in most cases require a computer
scan tool to extract the codes.
When you start your vehicle, the “Service Engine
Soon” or “Check Engine” light should
come on briefly. This indicates the OBD
system is ready to scan your vehicle for any problems
or malfunctions. After this brief period, the light
should go off and stay off while you drive, as long
as no problems are detected. If the light should come
on and stay on, the OBD system has detected a problem
or malfunction that should be addressed by an automotive
technician. These problems can be either minor or major
and could be alerting the driver to vehicle conditions
that can cause excessive air pollution, wasting of fuel
or possible engine or component damage. If the light
is blinking, a severe problem is occurring and should
be addressed as soon as possible.
The NC DMV now requires the emission inspection performed
on 1996 and newer vehicles to be done through the computer
system on your vehicle. If the “Service Engine
Soon” or “Check Engine” light is on
at inspection time, the vehicle will fail the emission
As a professional automotive repair facility, we employ
trained OBD technicians and use up-to-date OBD scan
tools and diagnostic equipment. These will enable us
to diagnose and repair problems quickly and accurately.
However, as the vehicle owner, you should understand
the process for diagnosing and repairing problems created
by the malfunction indicator light (“Service Engine
Soon” or Check Engine”).
When the malfunction indicator light (MIL) is on, there
could be one diagnostic trouble code (DTC) or multiple
diagnostic trouble codes. There could be one problem
present or multiple problems present. There could be
one DTC, but more than one problem or no DTC’s
and the vehicle still exhibiting a problem. The OBD
system performs a series of “self-tests”
to determine whether all systems are working as designed.
Once a failure occurs, many of these tests are temporarily
turned off. This means that once we fix the problem
that caused the original code to set, we may discover
other problems that could not be detected until the
first problem was solved. This is especially likely
if you have been driving with the malfunction indicator
light on for some time.
Some self-tests; require certain specific conditions
to occur before they can run. Some, for example, may
require that the engine not be started for at least
eight hours since the last trip, and then when it is
started, the outside temperature must be warmer than
15 degrees. Others require that the fuel tank be between
one-half and three-quarters full. Most require that
the vehicle be driven for several minutes at a steady
speed of more than 50 mph. There are many other requirements
for each self-test, and all must be met before those
tests can run. Additionally, some tests must be run
more than once before they will register a failure.
It would not be practical for us to keep your vehicle
and drive it so extensively. That’s why we must
rely on you to do your part. Each of the OBD self-tests
will run eventually during normal driving. You will
need to bring your vehicle back for further repairs
if the MIL illuminates.When you pick your vehicle up
after it has been repaired, we will list on the repair
invoice, the specific codes present in the computer
diagnostic scan. That way if the MIL comes back on,
we will know if the DTC’s are new or repeated
from a previous problem.
What does the tire pressure monitoring
Our government has passed legislation that requires
all new passenger vehicles, beginning with 2008 model
year vehicles, to be equipped with a tire
pressure monitoring system.
Maintaining the correct tire pressure for a vehicle
is imperative for it’s safe operation. Too little
air pressure will eventually cause catastrophic tire
failure, which may endanger occupants safety. Studies
have shown that running tires with too little air pressure
is not uncommon. This means drivers are needlessly sacrificing
their vehicle’s fuel economy, handling, tire durability
and tread life.
Legislation requires that a pressure monitoring system
alert the driver when air pressure in a tire drops at
least 25 % below the recommended cold tire inflation
pressure for the vehicle. There are two types of air
pressure monitoring systems used on vehicles today,
direct monitoring systems and indirect monitoring systems.
Direct systems attach a pressure sensor/transmitter
to the vehicle’s wheel inside the tire’s
air chamber. This system will measure, identify and
warn the driver of low air pressure and tends to generate
more accurate warnings. On some vehicles, this system
will identify by position which tire is low and what
the pressure reading is.
Indirect systems use the vehicle’s anti lock
braking system’s wheel sensors to compare the
rotational speed of one tire versus the other three
positions on the vehicle. If one tire is low on pressure,
it will roll at a slower rate than the other three tires,
and through the onboard computer will alert the driver.
Unfortunately, indirect tire pressure monitoring systems
have several shortcomings. This system cannot tell the
driver which tire is low on pressure and will not alert
a driver if all four tires are losing pressure at the
same rate, such as during colder months. Also, false
warnings can be triggered by loss of traction when tires
slip on slick surfaces.
To conclude, tire monitoring systems are a valuable
tool for the driver of a vehicle, but should not eliminate
the periodic air pressure check needed to keep tires
What do the numbers mean on
the sidewall of a tire?
As our example, the tire information used will be P245/70R16
The first letter designates the tire type.
P for a passenger vehicle tire, LT
for a light truck tire and T
for a temporary or spare tire.
The next three numbers denote the tire width in millimeters,
measured from sidewall to sidewall. In this example,
the width of the tire is 245 mm.
The next pair of numbers is the aspect ratio. It tells
the height of the tire from the bead to the top of the
tread and is a percentage of the tire width. In the
example, the tires height is 70% of 245 mm, or 171.5
mm. High performance tires usually have a lower aspect
ratio than other tires. This is because tires with a
lower aspect ratio provide better lateral stability.
Tires with a lower profile have shorter, stiffer sidewalls
so they resist cornering forces better.
The letter R indicates
that the tire was made using radial construction. Older
tires were made using bias ply construction.
The number 16 specifies, in inches, the wheel diameter
the tire is designed for.
The final set of numbers and a single letter gives
the service description of the tire. The service description
consists of two things:
* Load Ratings:
The load rating is a number that correlates to the
maximum rated load for that tire. A higher number
indicates that the tire has a higher load capacity.
* Speed Rating:
The letter that follows the load rating indicates
the maximum speed allowable for this tire. For instance,
S indicates that the tire can handle speeds up to
112 mph. Other speed ratings include T, V, and Z and
indicate higher tire speeds.
Also on the sidewall of the tire is the uniform tire
quality grading information.This rating tells you three
* Tread Wear:
This number comes from testing the tire in controlled
conditions on a government test track. The higher
the number, the longer you can expect the tread to
last. Since no two people drive exactly alike, this
number is not an accurate indicator of how long your
tread will last but information you can use to compare
Tire traction is rated AA, A, B, or C, with AA at
the top of the scale. This rating is based on the
tire’s ability to stop a car on wet driving
surfaces. It does not indicate a tire’s cornering
The tire temperature ratings are A, B, or C, with
A being the better rating. The rating is a measure
of how well the tire dissipates heat and how well
it handles the buildup of heat. The temperature grade
applies to a properly inflated tire that is not overloaded.
Under inflation and/or overloading can lead to excessive
heat buildup and can cause tires to wear out prematurely
or can lead to total tire failure.