Coping With an Oil Slick in the Garage

Times Staff Writer

Question: I have a 1979 Oldsmobile Cutlass. For the last several months, it has been spotting oil on the garage floor. I took it to a mechanic, and he said that some seals had deteriorated. The repair was $150. The dripping persisted, and another session with the mechanic was another $150. It still drips, although I don't lose enough oil to show on the dipstick. But it is a messy annoyance. Can you help me?--A.M.A.

Answer: It is a rare car that doesn't drip a little oil after it's 5 years old. Engine heat causes seals and gaskets to become brittle and crack, allowing the oil to seep through. Drips on the garage floor and driveway are annoying, but the only way to really solve the leaking problem may be to tear the engine apart and replace all the gaskets and seals.

A less-expensive solution is to put something under the car to catch the drips. You can buy an oil drip pan at an auto-parts store. Or you can tear up a large box and lay the cardboard flat on the floor under the engine.

Q: My 1979 Dodge Diplomat was running badly, and a mechanic kept trying to repair it by replacing the spark plugs--to no avail. Finally, someone told me that because I don't drive the car much, I needed to take it on the freeway to blow the carbon out of the engine. I did it and the car runs better. Is this something I'll always have to do?--S.N.

A: If you drive your car on a lot of short trips on city streets, deposits that collect in the combustion chambers will affect the engine's performance. The air-fuel mixture is relatively rich in gasoline when the engine is cold, and if you just take a short trip, the engine doesn't warm up properly, allowing unburned hydrocarbons to build up inside the combustion chambers and on the cylinder walls. Carbon can also foul the tips of the spark plugs, preventing them from properly igniting the fuel.

Driving the car occasionally at highway speeds can keep the deposits from building up and can clean out existing deposits. The more rapid combustion burns off the carbon buildup. The best way to "blow out" the carbon is to accelerate rapidly to a high speed.

Q: The red alternator warning light in my 1980 Pontiac Phoenix comes on about half-bright occasionally. I have already spent more than $200 trying to find the reason, including replacing the voltage regulator and the battery and having the alternator checked, with no results. Will putting an ammeter in to replace of the warning light solve anything?--L.S.

A: If the problem is under the hood, replacing the light with a meter will not solve the trouble, but it could tell you more precisely how serious the trouble is. The red light is designed to come on when there is a flow of current between the battery and the alternator, which occurs if one of the components is putting out more electricity than the other.

The most common cause of a glowing warning light is a loose or slipping alternator belt. If the belt that drives the alternator is slipping on the pully, the alternator won't put out enough electrical current to meet the needs of the engine, and the battery has to make up the shortfall. This causes the light to come on dimly.

But the trouble could also be in the instrument panel itself, particularly if the light comes on only intermittently. You could have a short circuit that allows electrical current to reach the warning light and cause it to glow.

If the belt is tight and tests show that both the alternator and voltage regulator are working properly, have your mechanic check for a short circuit under the dash.

Copyright © 2019, Los Angeles Times
EDITION: California | U.S. & World