OVERHEATING

Rotorua Morning Post, Volume 1, Issue 110, 31 December 1931, Page 2

OVERHEATING

SOME OF THE CAUSES Although much less common than it was a few years ago, overheating of car engines continues to be one of the faults against which owners must guard. It is most frequent in the summer when the dissipation of heat from the radiator is retarded by the high atmospheric temperature, and it is especially likely to occur on hills, where the engine, driving the car in a lower gear, revolves rapidly, but is deprived of at least part of the air stream generated by a car in rapid motion to assist cooling. In a bulletin on the overheating of engines, General Motors suggest many factors which may cause this defect. ' Among the most prolific and most evasive are well-worn hose eonnect'onr. in which the inner ply of rubber may rise into a lump obstructing the water flow, but without external evidence of the obstructions. After a long period of use a long lower hose is likely to collapse under the suction of the water pump when the en- | gine is running fast. The influence : of a worn or loose fan belt on overheating is familiar, but many driv1 ers do not realise that the set of the fan blades can be nearly as important, especially as they may be incorrectly adjusted in repairs after an accident. Delayed opening of thermostat or thermostatically controlled radiator shutters is a cause of overheating best left to a mechanic to rect'fy. Paint, mud, or insects on a radiator core will impair its heatdissipating capacity, and the same result follows the 'placing of a number plate or a large headlamp in the middle of the radiator. A lean mixture causes a hot and inefficient power stroke which assists in overheating the engine. Incorrect timing of the spark or the valve camshaft have similar effects. Oil of improper grade, or oil from which the body has been lost by two long use, also cause overheating, in this case of a dangerous eharacter, as it is the result of excessive friction in the cylinders. Any' fQrm of water loss from the radiator is a potential source of overheating and it should be corrected as soon as . noticed. Obstruction of the radiator pipes by scale, rust, or dirt introduced with the cooling water will also cause overheating in warm weather.