Question: I had two new tires put on the front of my Chevrolet Impala, and the next day I had a flat on the right-front tire. The service station determined the leak was from a crack in the rim. After putting a tube in the tire, the service station guaranteed that it would be OK. My question is: How safe is it to drive with a cracked rim on the wheel?--L.R.N.
Answer: A cracked wheel is of questionable safety and may well be an outright danger in your case. You should immediately install either a new wheel or a used wheel in good condition.
Cracks in metal often result from metal fatigue, corrosion or impact damage. In all of these cases, the crack indicates that the metal is weakened and vulnerable to failure. The fact that air is leaking out of the crack is even more convincing evidence that it is fairly large and possibly growing.
A crack that occurs along the rim of a metal wheel, where the bead of a tire seats against the wheel, is a particularly dangerous situation. You have to remember that tires reach 35 pounds of pressure per square inch in highway driving, and that pressure exerts thousands of pounds of force against the metal wheel. A weakened wheel can split, causing a blowout or even a total loss of the wheel.
You can purchase a new wheel for between $20 and $50. That's well worth your safety. At the very least, you should substitute the cracked wheel with the spare from your trunk until you get a permanent replacement for your spare.
Q: I have a 1980 Buick Century. When I turn on the ignition to start out in the morning and back up, the motor immediately dies. When I get out into the street, the motor dies again. What do you think is wrong?--B.P.S.
A: Your engine is probably not receiving a rich enough fuel/air mixture when it is cold. Some part of the choke system is not operating properly.
The choke system is designed to give the motor a richer mixture of gasoline when the engine is cold. On older cars, the choke itself is a fairly simple device that is controlled by a heat-sensitive spring.
On newer cars like yours, however, the choke system includes numerous mechanical and electronic elements. Your car has an electric choke, an exhaust-gas recirculation system, a heated-air cleaner, an early fuel-evaporation valve and a vacuum brake on the choke plate.
Your car needs a thorough check to determine which of these systems is causing a lean fuel mixture in the first few minutes of operation.
Q: I have a 1981 Toyota Corolla station wagon with 32,000 miles, and I am beginning to detect gasoline fumes when I open the car door in the morning. These fumes are noticeable before I start the car. I understand Toyota is aware of the problems with these fumes, but the dealer said they know nothing about any bulletins from Toyota. Could you shed some light on the matter?--F.C.
A: Your problem with raw gas odors is somewhat different from complaints by other Toyota owners of a rotten-egg odor that occurs during operation.
The smell of raw gas may be an indication that your fuel charcoal canister needs to be replaced. The charcoal canister is an emission-control device that soaks up gasoline fumes from the fuel system before they escape into the atmosphere. You should also have your mechanic check all gas and vapor lines to make sure they are tight.
Ralph Vartabedian cannot answer mail personally but will respond in this column to automotive questions of general interest. Do not telephone. Write to Your Wheels, You section, The Times, Times Mirror Square, Los Angeles 90053.