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 and loads.

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 oil.

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 and tear.

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 inspection.

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 system do?

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 properly inflated.


What do the numbers mean on the sidewall of a tire?

As our example, the tire information used will be P245/70R16 106S

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 things:

* 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 different tires.

* Traction:
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 ability.

* Temperature:
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.