Auto Service World
News   August 8, 2003   by Auto Service World

Professionals Debunk Automotive "Wisdom"


Should you warm your car in the winter? What does it mean when your steering wheel shakes? The answer may not be what many car owners believe, according to professional service specialists.
A group of professional technicians who are part of the DaimlerChrysler service network have put together a list of some commony misconceptions about proper automotive care and treatment. The facts may surprise.

True or false: You should always warm your car up before driving on a cold day. The answer is false. Although the majority of the driving population may consider this to be true, it can actually cause damage to vehicles if done continuously.

Belief: Do not blast your vehicle’s air conditioner when sitting in traffic or while driving at more than 100 km per hour.
Reality: False. Vehicle heating, ventilation and air conditioning (HVAC) systems are engineered and tested to operate in even the most severe types of driving environments. The air conditioner has cooling fans and condensers that allow it to operate under these conditions.

Belief: It is possible to check your tire tread with a penny.
Reality: True. Although the service specialists you use a proper tire gauge to check tires, it is possible to check tire tread with the use of a penny. Simply pinch a penny between your thumb and forefinger so the Queen’s head is showing. Insert the penny into a tire tread groove. If the tire covers any part of the head, then your tires should have a safe amount of tread. If you can see the head in its entirety, it is time to invest in a new tire. Be sure to check all tires and in different locations on each tire because the amount of wear can vary from tire to tire and from inner tread to outer tread.

Belief: If you still have fuel in your gas tank when you refill it, use the same grade of fuel that is currently in the tank.
Reality: False. As long as you use unleaded brands of gasoline, it will not harm your vehicle if you mix different grades of fuel.

Belief: Avoid keeping your vehicle at a constant speed during the first 500 miles of a vehicle’s life.
Reality: Maybe. Most new vehicles no longer require drivers to vary their speeds during the first 500 miles of a vehicle’s life, known as the “break-in period.” If your vehicle does require the “break-in period,” then you should avoid keeping a constant speed during this time. Even varying your speed by several miles per hour should do the trick (of course, within legal limits).

Belief: Your vehicle’s engine should be “warmed up” before driving in cold weather.
Reality: False. Warming your engine up, or idling, is not the best route to take. In fact, excessive idling can be damaging to your vehicle. You should, instead, drive the vehicle to get the engine warm during the cold weather.

Belief: Premium gasoline is best for your vehicle.
Reality: Maybe. It depends on the type of vehicle you drive. Most cars are built to run on regular-grade fuel, so using premium fuel will not improve the car’s performance. In fact, using premium fuel in a vehicle that was not designed for it can harm the vehicle’s performance and fuel efficiency. Check your owner’s manual for recommended fuel grade.

Belief: For city dwellers dealing with narrow streets, do not park with two wheels on the curb, as it will destroy the vehicle’s alignment.
Reality: True, if done continuously. The service specialists say that repeatedly parking a car with one side’s wheels up on a curb to provide more space for passing cars can cause excessive wear or stress to tie rods and suspension bushings, and could create alignment issues.

Belief: If the steering wheel shakes when you drive, there is something wrong with your brakes.
Reality: Maybe. If the wheel shakes as you depress the brake pedal, it may mean your brake rotors are unbalanced. If the wheel shakes as you drive, it may be the result of a wheel balance or steering-related issue.