WHAT GIL-GAUGE TELLS

NZ Truth, Issue 1194, 18 October 1928, Page 21

WHAT GIL-GAUGE TELLS

You ShouM Understand Language . Of The Needle

THE most important unit on the instrument board by a long way / ; is the oil gauffe, but the information it gives is more often than not misunderstood; ; .;

T7HE pipe to the gauge 'usually comes 1 direct from the oil pump inside the . . engine. It has no connection with the main oil feed 'pipe's running to the bearings, and consequently is not a reliable guide upon; the subject of , those bearings. ; '•'•.' What. .the. gauge - really tells the driver is that, the engine oil pump is working, and that the bearings are probably receiving oil, that .the oil is moving with difficulty or with freedom through the oil pipes, and' that the level of the lubricant m the sump is correct or becoming low. ■' When the engine is started on a cold morning, the oil, being relatively thick, requires more force /to drive it through the pipes; consequently the oil pressure gauge then registers a very high pressure. • . This means that the oil is. not circulating .freely, and the engine, therefore, should not be run fast for a time. When the gauge needle drops to normal, the; oil, having' become heated by its, passage through the engine, has returned to its usual viscosity, and it is safe to open the throttle. A point to remember, however, is that the oil gauge may continue to stand at, say, 301 b., even if one bearing is. not receiving any lubricant at all, for the- pipe leading- tq. that bearing may be blocked. ,■ ■'.-'■ On the other hand,' if the oii;. pressure falls from, say, 301 b., to 101b., -the

fact that the gauge still registers 101 b. shows that the oil pump is 'working, but that there' is something amiss, and a drop of this nature is so serious that the best procedure is to have the en*gine sump dropped, and '. the mischief located before, more harm is done. Any neglect may result m a big repair bill. ,■ . If the oil m the sump gradually drops to a low level it is usual for the needle of the gauge to fluctuate, particularly on a corner, Where, it may read zero at one moment and 101 b. at the next. v ■ ■ '.' . On some cars the gauge will ; show zero when running downhill and go up to 101 b. when the car reaches the level. That indicates that more oil is required at once m the sump. How dust collects all over the engine is well known to all car drivers; particularly those who take pride« m looking after their., motor. . The engine, as it runs, naturally, ab-' sorbs a great deal of this road dirt, and at normal speed, the carburettor sucks m air at a Velocity of more than a mile a minute. Entering the engine, much of this mixes with oil on top of the pistons, and is baked into slag, which is commonly called carbon. ' . ... •■■'• It has been' estimated that' 75 per cent, of carbon comes from road dust, but- that which becomes' carbon' does* the> least damage. ; . '