A solution composed of 60% of water, 10% of glycerine, and 30% of alcohol is commonly used, its freezing point being 8° below zero.
Evaporation.—On account of evaporation, fresh alcohol must be added frequently in order to maintain the proper solution.
Radiator Repairs.—A small leak may be temporarily repaired by applying brown soap, or white lead, but the repair should be made permanent with solder as soon as possible. A jammed radiator tube is a more serious affair. While the stopping up of one tube does not seriously interfere with circulation, it is bound to cause trouble sooner or later, and the tube will freeze in cold weather. Cut the tube an inch above and below the jam and insert a new piece soldering the connection. If the entire radiator is badly jammed or broken, it will probably be advisable to install a new one.
Air Cooling System.—Air cooling has been developed to a point where fairly good results are attained. This system has an advantage over the circulating systems, in that the weight of the radiator and water is done away with, and no trouble is experienced with stoppage of circulation and leaky connection. This system, however, has its drawbacks, in that it cannot be used successfully on the larger and more compact engines. In order to allow the necessary large space for radiation, the cylinders are heavily flanged and set separately. The fan is placed in a much higher position than usual, in order that the air current may strike the heads of the cylinders and circulate downward. Compression is also lowered considerably to prevent heat generation and pre-ignition. On account of the small size of the cylinders and low compression, it is necessary to operate an air cooled engine at a very high rate of speed to produce sufficient power for automobile locomotion.
The fan must be kept in good working condition, and care should be exercised in not allowing the engine to run idle for any length of time.
CHAPTER XII
MUFFLER CONSTRUCTION, OPERATION AND CARE
The muffler was designed to silence the otherwise loud report of the exploding charge of gas, which is released from the cylinders by the sudden opening of the exhaust valves.
While these devices are differently shaped and formed, the functional purpose and action is practically the same in all designs.
The burnt or inert gases are forced from the cylinders on the exhaust stroke. It passes into the exhaust manifold which absorbs some of the heat before it reaches the muffler.
