Battery Dies After the Twilight Hours
Question: My 1980 Dodge runs well but has a strange electrical problem that causes it to die out suddenly at night. The battery is dead when this happens. What could be the cause?--Y.N.
Answer: If the battery is running down only at night, you have either a fairly simple problem or a rather difficult one. It could be as simple as a loose fan belt that is unable to operate the alternator at peak electrical demand when the headlights are on.
The headlights are the largest single electrically powered device on the car, and when they are on, the alternator must work hard to supply an adequate current. The voltage regulator detects the electrical load being demanded by the various systems on the car and controls the generation of current. It also makes sure that the battery is fully charged.
The alternator is powered by a fan belt that runs between a pulley on the engine and a pulley in front of the alternator housing. When the alternator needs to produce more current, the pulleys become more difficult to drive. If the belt slips because it isn’t tight enough, then the alternator will not be able to generate all the current needed for the headlights and other systems on the car.
As a result, the battery begins to drain itself until it is so low that the engine simply dies. If the belt is loose, the solution is usually to tighten or replace the belt.
The more complex possible problem may involve a short in the headlight circuit that causes the electrical system to drain but not blow a fuse. That could occur almost anywhere in the headlight circuit. A mechanic should be able to determine just what the problem is.
Q: I recently filled up my 1972 Ford Mustang with Arco EC-1 fuel. The company says the gasoline is designed for older cars. Does that mean it contains a lead substitute?--M.K.
A: You might think because the new Arco EC-1 fuel is intended for use in older cars, which were designed to burn leaded fuel, that the fuel contains a lead substitute.
The gasoline contains neither lead nor a lead substitute, but the company insists that it is safe to use in engines that were designed to burn lead. The main difference between EC-1 and plain unleaded regular is that it carries the somewhat higher octane rating required by older cars.
Lead was used in the past primarily to boost the octane of gasoline and also to perform the function of cushioning engine valves and their valve seats. Under heavy usage, such as speeds in excess of 55 m.p.h. or when towing a trailer, old engine valves need lead or a lead substitute to cushion the surface between valve and valve seat.
But in the past two decades, scientists have discovered that lead was poisoning the environment and perhaps causing learning disabilities in children. Under federal law, it is being phased out.
Starting in 1974, automobile manufacturers hardened the valves and seats in engines so that they did not require lead. Some cars had hardened valves and seats starting in 1970.
In cars produced earlier, heavy usage can cause premature valve failure. Under heavy usage, motorists can use lead substitutes, which are based on sodium or phosphorus compounds and are readily available in auto parts stores. Generally, old marine engines, which are typically run under heavy loads, require a lead substitute most of the time.
