Question: I drive a 1984 Cadillac Eldorado with 40,000 miles on the odometer. It is an excellent car, but it is using quite a bit of oil. Now I have another problem. After about five miles of driving, the car develops a heavy emission of white smoke on acceleration after stopping or slowing. What is the cause and how can I eliminate this embarrassing problem?--E.K.
Answer: The emission of large quantities of smoke from a tailpipe usually can be traced to one of several conditions, which in addition to being embarrassing are quite often costly to repair.
A dark black smoke usually is caused by an overly rich fuel mixture, which is being only partly burned in the engine. A bluish smoke indicates that a large amount of engine oil is being drawn into the engine combustion chamber and burned.
The white emission that your Cadillac is billowing may not be smoke at all but rather steam. It is possible that you have an engine gasket leak, most likely in the head gasket, which is permitting coolant to work its way into the combustion chamber.
Such head gasket leaks, depending on where they are located, often pass exhaust gas into the coolant system or water into the engine. If the leak borders the combustion chamber, usually high-pressure exhaust gas will force its way into the cooling system. If the leak borders a manifold passage, however, the water can leak into the intake or exhaust manifold.
The fact that the smoke appears during times of aceleration and deceleration would be consistent with water-pressure changes that occur at those times.
In either case, the condition is easily diagnosed. Your mechanic should be able to check the pressure level in the cooling system and analyze the composition of the exhaust gas. A head gasket leak also could be allowing lubricating oil to be burned in the engine. This also is easily determined by a mechanic.
Q: I have a 1985 Toyota Celica with fuel injection. For some reason, the owner's manual does not include any mention of a replacement schedule for the fuel filter. How come?--J.S.J.
A: The reason is simply that the originally equipped fuel filter is supposed to be a lifetime fuel filter. The diameter and the filtration capacity of the filter is much greater than the typical filter, and unless you have specific problems, Toyota does not recommend replacing it.
At the same time, it's noteworthy that many fuel-injection systems are experiencing tremendous problems with clogging of injectors due to contaminated gasolines. Nevertheless, auto manufacturers are making a huge effort to eliminate regular service items, such as fuel filters, to help market their cars as "maintenance free."
Some experts are raising questions, however, about whether the lack of regular service is going to cause higher maintenace costs in the long run. You may want to consider replacing the original filter after the car has 75,000 miles.
A recent column, which discussed the use of snow chains on four-wheel-drive vehicles, indicated that if only one set of chains is used, then the chains usually go on the rear wheels. The general rule is that you should use the chains on the primary drive axle, which on most four-wheel-drive vehicles is the rear axle. But the final authority on this is the owner's manual or the manufacturer's recommendation.
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.