Car Gauges-what they are and their importance for new driver
I just purchased a nice used car for my sixteen year old daughter to drive. Among all the care and usage recommendations I have given her the one thing she’s most perplexed about are the gauges. Can you please explain them and their importance? Also any other tips for a new driver to keep her safe and the car in good condition? Thanks!
— Anita P.
Sure! Many vehicles employ instrumentation beyond just vehicle speed and fuel level. Let’s look at each:
Tachometer, this displays engine rotational speed. Most engines idle at perhaps 600-700 revolutions per minute (RPM) and have a maximum RPM of maybe 5000-7000 RPM. An automatic transmission will typically choose an appropriate gear that best meets power requirements while minimizing fuel use. Higher RPM delivers more power, lower RPM promotes fuel economy. It’s prudent in most cases to run at the lowest RPM possible that delivers needed performance.
Temperature (thermometer symbol): This gauge spans from perhaps 100-260 degrees F. The normal operating temperature of most engines is 195 degrees, the engine should warm up to this level within a few minutes of driving. Temperature may climb somewhat in traffic between cooling fan cycles, or climbing long grades. A reading of 225 degrees would catch my attention, if it drops back down after a given condition, it’s not a concern. Above 240 is of high concern, damage may occur at/above 260! One should keep in mind that overheating an engine can be very destructive, and should be avoided at all costs! An engine that runs too cool should also be checked, but this is of much lower concern.
Oil Pressure (oil can symbol): Like blood pressure this one is vitally important, and higher is better! Typical readings vary from perhaps 15-20 PSI (pounds per square inch) at idle to about 40-70 PSI at higher engine speeds. Pressure is typically higher when the oil is cool/thick and drops somewhat when warm/hot. If the engine is filled to the proper level and oil is checked and changed regularly, an oil pressure fault (low or 0) is incredibly rare.
Voltage (battery symbol): This displays the status of the charging system/battery team, and higher is better — to a point. Key on-engine off, one will see about 12.6 volts, a charged and static battery. A typical running voltage is 14.5 volts (charging is ongoing and successful). At idle with many accessories functioning, this may dip a bit. The most likely fault one might see (perhaps a vehicle with 150K miles or so) is voltage drops to just battery (12ish) while driving (charging is not occurring). Head for home right away with reduced accessories used!
How often should gauges be checked? Ideally a quick visual sweep of all gauges every few moments is best. Or at minimum, an occasional peek when climbing hills (temperature). Some vehicles (I wish all) employ a “Check Gauges” light or tone when something is amiss, and others employ just red warning lights in lieu of gauges, which is unfortunately information too little-too late…
My short list for sparing mechanicals of unnecessary abuse: Apply the parking brake EVERY time, before placing transmission in park. Select a lower gear on moderate to steep hills (spares the brakes from heat abuse, 2500-3000 RPM provides helpful hold-back. Renew brake fluid and coolant, belts and hoses every 4-5 years. Consider a sun windshield shade to protect the vinyl instrument panel. Clean/wax paint every six months, keep seat seams free of sand/debris.
Out of space!