WATCH THE INSTRUMENTS

Wairarapa Times-Age, 22 April 1938, Page 4

WATCH THE INSTRUMENTS

KEEP A CHECK ON THE ENGINE. ADVICE TO MOTORISTS. One of the best habits the motor owner can form is that of glancing at the instruments frequently during the course of a day’s run. The story they tell of engine efficiency is complete, and their warning of impending trouble immediate. The warning is given, indeed, some time before the trouble has developed to a serious stage. It may be said that this statement is axiomatic, and not worth putting into print, but how many motorists fail to look at their instruments from one week’s end to another? Any service station can tell of ruined batteries, burned out bearings, and of motorists running out of petrol. All of these mishaps could have been forestalled had the drivers concerned taken the trouble to read the message of the instrument dials.

A car will run a surprising number of miles after the oil pump ceases work, before that horrbile clatter and thumping beneath the bonnet tells the owner that about the very worst thing that can happen to an engine has happened. At any time during that period the switching off of the engine would have meant the difference betwen repairs to the oil pump, a comparatively simple and inexpensive matter, and new bearings, together perhaps with refacing of the crankshaft, a most expensive procedure.

These instruments are put into a car for a very definite purpose, and because of the design of modern cars they are the only things to-day which warn the driver of impending trouble. Not that trouble is of frequent occurrence, but no mechanical contrivance is perfect, and some mishap may occur at any time.

Suppose a motorist owns a car which uses so little water that he gradually forms the habit of not looking,at the radiator level more than once in two weeks. There are many such cars. Suppose he also never looks at the water pump—and how many motorists do?—and the gland packing of this gradually wearing service allows some of the water to escape till it reaches such a low level that the engine boils. In most modern cars, the radiator filler cap is beneath the bonnet, so that the driver will not see the steam coming from it as he would in one of the old models. Unless he notices the warning given by the radiator thermometer on the instrument board, the next thing he will hear is the knocking of an overheated engine.

The same thing applies to the generator. The ammeter is the only thing which will tell him whether the generator has ceased to charge or whether some short-circuit in the wiring system, carrying with it the danger or fire, has developed. But the instruments must be read intelligently. On rare occasions, one or two of them can be quite misleading. If, for instance, the electrical system is fitted with a voltage regulator system instead of the old third brush method of maintaining the charging rate at a constant figure, irrespective of battery condition, it will be possible for the owner to receive quite a fright on a long run when he notices the ammeter needle pointing steadily to the zero mark. This may indicate trouble, but it may not, because if the battery is fully charged, the generator stops charging. An easy method of finding out whether this is the explanation is to switch off, use the self-starter, thus ' putting a fairly heavy drain on the battery, and then notice whether the ammeter again registers some charge. If it does, then there is nothing wrong. Again, when an engine is switched off, the hottest portion of the cooling water will rise to the top of the radiator and stay there. As the thermometer unit is inserted here, the dashboard gauge will register a higher temperature until the engine cools off or until it is started again, a perfectly normal state of affairs.