Question: I am desperate for an answer to this problem. The smell of raw gas permeates the inside of my Plymouth Reliant. It makes me ill, forcing me to drive with the windows open. I have had the car to the dealer, and they deny that the problem exists.--P.M.
Answer: One simple possibility is that you are overfilling your gas tank. Car owners often overfill their gas tank at the pump by relentlessly topping off the tank.
Automobile designers put an air pocket in gas tanks to prevent the tank from becoming too full, but if you try long enough to top off your gasoline tank, you will defeat the purpose of the air pocket.
With no air pocket in the tank, the gasoline is unable to expand in the tank, which it will do on a hot day. Where does the gas go? To the gasoline-vapor canister, which is located inside the engine compartment and connected to the gas tank by rubber hoses.
The canister is intended to collect vapors from the gas tank to prevent pollution. It's not intended to take liquid overflow from the tank. If it becomes saturated, the charcoal filter inside the canister is ruined and will not do an adequate job of trapping gas vapors in the future.
Your mechanic should also check for a leaky gas line, gas filter or carburetor. A leak would pose some hazard because of the potential for fire, so have that done immediately.
You also should check to make sure that the engine is not flooding due to an improper choke setting. A stuck choke will flood the engine with gas and can dilute the oil. That can cause costly engine damage, which will make you doubly ill.
Q: I have a 1973 Buick Century V-8. After 11 years, the heater finally gave out. It was replaced, but 13 months later it gave out again. I noticed a strong ammonia-like odor at the time. I have always used Prestone II, but the last bottle I used had been open for three years. Could the antifreeze have gone bad?--E.M.
A: The odor you smelled was not ammonia, and the antifreeze did not go bad.
Antifreeze is a very stable chemical product and has an almost indefinite shelf life. It is unrelated chemically to ammonia. Prestone, like almost all antifreeze, consists chiefly of ethylene glycol, a member of the alcohol family that is produced from petroleum or natural gas. Ammonia, consisting of nitrogen and hydrogen, is not a petroleum product.
The pungent odor you describe probably resulted from impurities in the antifreeze leaking onto hot engine parts and vaporizing. Although antifreeze is almost odorless when it goes into a radiator, after a year the impurities that collect in it can smell pretty bad.
Q: I own a 1975 Datsun 280Z, which has an intermittent starting problem. At times the engine doesn't start but it will crank. There is no spark coming out of the ignition coil. I changed the coil but that wasn't the problem. What could be the matter?--F.S.
A: You probably have an intermittent open or short circuit in your system. You should focus on the ignition module or main control box inside the passenger compartment, which has a 35-pin electrical connector.
Corrosion could cause an intermittent open circuit. You might consider spraying LPS or WD-40 on the connections. Those products displace moisture.
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.