Question: The owner's manual on my 1986 Dodge Aries says it should hold four quarts of oil, and it cautions: "Do not overfill crankcase as this will cause oil aeration and loss of oil pressure." But the dipstick shows full after I add only three and one-fifth quarts of oil. What is the correct amount of oil?--R.G.
Answer: The problem you observe is not at all uncommon among car owners who change their own oil. It's seldom the case that the dipstick shows exactly full when you add the amount of oil recommended in the owner's manual.
The specification calling for four quarts of oil is generally the one you should follow, because the engineers who designed the motor want four quarts of oil in it, based on the cooling and lubrication needs of the engine.
There are several reasons to explain the paradox. First, the four quarts suggested in the owner's manual includes the oil inside the oil filter, and if you do not change the oil filter, there would be some old oil remaining in there.
Second, if you change the oil when the engine is cold or the car is parked at an angle, a lot of oil will not properly drain out. The car needs to be hot and level to properly drain all the old oil.
Another factor to consider is that some manufacturers specify the oil capacity in terms of a dry engine, which always needs more oil at its first filling. That's not the case with your Dodge, but some Japanese car specifications are stated this way.
Finally, manufacturers almost always round off to the nearest quart the recommended amount of oil to be added during a change. An extra half-quart of oil is unlikely to damage the Chrysler engine.
Q: I have a four-headlight system in my 1984 Caprice. I was thinking of replacing the driving lamps with halogens, but have heard they draw a lot more current. Is their life as long as standard lamps?--R.F.
A: Halogen lamps generally draw much less current than a standard tungsten filament bulb. Halogen bulbs will generate 30% more light on the same amount of electrical current, but they are generally designed to draw less current and produce about the same amount of light as a standard headlamp.
The lamps create a whiter light and less scattered beam, which may improve your night vision by a small amount. They help much more in high beam.
The downside to these headlamps is that they are more expensive to purchase, and they can fail after substantially less usage than standard bulbs in many cars. The filaments are made of wire that is about one-half the diameter of a tungsten filament and the bulbs contain high pressure. A voltage surge or hard vibration can cause catastrophic failure in some cases.
Q: I bought a 1986 Olds Delta 88, and since the first week, there is a smell of rotten eggs in the car. I took it to dealers twice and was told it would go away. Is this a common condition?--C.K.
A: It is becoming distressingly more common in today's highly tuned cars that aim to get high mileage, meet stringent pollution laws and provide reasonable performance. The smell is a hydrogen sulfide gas, which manufacturers blame on high-sulfur crude.
You might switch brands of gasoline to one that is refined from a low-sulfur crude. That seems to be the easiest solution to the problem. Altering the car's carburetion settings might help, but it would probably put you out of compliance with emission laws.
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.