For running at low temperatures it will be found desirable, if indeed not necessary, to keep the anti-freeze solution from cooling too rapidly and thus retarding combustion in the cylinders. Most engines run better in the winter when the fan is disconnected by removing the belt. When it becomes very cold, however, other means must be provided in the way of radiator covers. These may be procured at any supply house, fitted to any car. They are in various forms, usually with a curtain which may be lifted for moderate temperatures and closed when extremes are reached. Anything which will cover the air spaces of the radiator may be used in an emergency, if one is caught by a sudden drop in the temperature. A blanket, a bag, even a newspaper or wrapping paper tied on will work properly until better provision can be made.
Care of the lubrication system is needed also in cold weather, since oil does not flow the same when cold as when warm. Most manufacturers give a schedule of oils for different seasons and this should be followed explicitly for best results. The owner should make sure that the oil is feeding through the system. If there is a dash sight feed it should be watched, for while oil does not freeze, it does get very viscid and, like molasses, flows stiff at low temperatures. However, winter lubrication has been studied by engineers for a quarter of a century and oils which are suited to all climes and all extremes are no novelty. The manufacturer is the best judge of the oil which will work most satisfactorily in the machine he turns out; besides, general advice could not be given which would apply to all cars. As a rule the man who sells oil should not be taken as an adviser in lubrication. In case of doubt go to the service station, if within reach, for advice.
This does not mean that an owner should not substitute a different brand of oil when he cannot get the one the manufacturer specifies; but he should get a corresponding quality and then watch results closely until a supply of the right kind is available. Experience and study will be a sufficient guide for the careful owner.
CHAPTER XXIX
OVERHEATING THE ENGINE IN SUMMER
The automobile engine will heat up too quickly in hot weather, just as an individual will. No, we did not say overeat; though if you let the engine gorge itself too long on motor fodder, it will help to overheat as well as overeat. There are a variety of reasons for the overheating, which it is well for the novice to understand.
Those who have found it necessary during the winter to cover the radiator and take off the fan belt and do other things to keep the engine hot enough to run smoothly and with the proper vaporization and firing, may find in summer that they are having as much or more trouble in keeping the engine cool enough to run properly.
Generally speaking, the nearer to the boiling point we can run the engine without actually having the water boil and steam away, the more efficient it will be. Some engines, in fact, develop much less than the maximum horse-power because they are too well cooled, and yet we hear a great many complaints about the water boiling in the radiator and the engine overheating.
This would not occur if everything were working as the designer intended it should. During cold weather the man who drives with a retarded spark uses up more gasoline than necessary, but he is not bothered with overheating. When the mercury goes up he finds that his engine overheats and gives him trouble. He has not changed his manner of driving, and cannot understand why there should be trouble.
Driving the engine at high speed with the spark retarded is one very good way of overheating the engine. As a matter of fact, the battery ignition systems which are now coming more into use require considerable manipulation of the spark-control lever, and the tendency is, because the engine knocks at low speed, to leave the lever partly retarded, instead of advancing it, when a higher speed is reached.
With the magneto, it is the general practice to advance the lever to three-fourths or seven-eighths of the full range right after the engine is started and leave it there for practically all work, except very high speeds. This may be done largely with such a system, because the nature of the spark given by the magneto changes somewhat with the speed of the engine, and the equivalent of an automatic advance and retard of the spark occurs with the variation of speed of the motor. With the battery system, however, there is very little change in the nature of the spark effected by the engine speed.