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Tire Air Loss May Have Many Origins

Times Staff Writer

Question: The tires on my 1979 Datsun 210 leak air, and I haven’t been able to determine why. The car was equipped with bias tires, which I replaced with four new radials after 22,000 miles. I have had the rims inspected, and they are not defective. Do you have a solution?--E.R.

Answer: Defective valve stems, which are the rubber stems used to fill the tires with air, can cause a lot of air leakage. They are an inexpensive addition to a tire change and should be replaced every time you buy new tires.

If that doesn’t solve your problem, you should have your tires removed and the rims on the wheels buffed so the tire beads will seat properly on the rims. Sometimes, corrosion or other surface irregularities will cause minor leaks where the tire seals itself against the rim.

One other possibility is that you have cast-aluminum wheels, which sometimes have pores that leak. You may have to replace such a wheel if it cannot be sealed.

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Q: I have a 1978 LTD with 37,000 miles on it. Last year, I noticed a terrible smell emanating from the car, especially after use and after backing up. My Ford dealer said it was the catalytic converters. I had them changed to the tune of $400. I still have the smell just as before. The odor is like rotten eggs. What is the cause?--J.A.P.

A: The Ford dealer was correct in telling you that the rotten-egg smell was coming from the catalytic converters, but the original problem probably did not start in the converters themselves.

The catalytic converters are located in the exhaust system and receive hot gases from the engine. They convert polluting fumes to harmless gases by use of special catalytic metals.

The rotten-egg smell might very well be the result of the converters overheating and burning up the special alloys inside. The overheating is likely to be caused by unburned fuel being exhausted from the engine.

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The unburned fuel could have many causes. Your mechanic should check the carburetor mixture to make sure that it is not too rich. Also, one of the cylinders may not be properly firing, which would expel quite a lot of unburned gas into the exhaust system.

Q: I have a 1974 six-cylinder American Motors Matador with 60,000 miles on it. I have to pump the accelerator 30 to 40 times to get the engine going the first time the car is started every day. After that, the car easily restarts. The choke has been replaced, and the carburetor has been checked. I don’t know what else to do.--J.B.

A: Pumping the accelerator 30 to 40 times is excessive, to say the least, and it’s surprising that you aren’t flooding the engine with too much gasoline. When you pump the accelerator, a small pump squirts additional gas directly into the carburetor.

If the engine is starting easily after the engine is warmed up, it is likely that you have a choke or carburetor problem. You can easily see if the choke is working on an older car by simply removing the air cleaner before you start the car in the morning. Press the gas pedal once to release the choke mechanism. A plate across the mouth of the carburetor should be closed. If it isn’t, you still have a choke problem.

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If it is closed, then the carburetor may not be getting adequate gas. Possibly, your carburetor float bowl, where gas is temporarily stored before going to the engine, has a slow leak. When the car sits overnight, it empties.

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.


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