Tacky or Techie? The Tachometer.
May 9, 2021
There's a gauge that many vehicles have that says RPM on it. And there are a lot of people who either don't pay any attention to it or don't even know what it is. Here's why it's a good gauge to know about.
It's called a tachometer, and that "RPM" label means it is measuring how many revolutions per minute (RPM) the engine is turning. Automotive experts know that a vehicle's engine can be damaged if it turns too fast (revving too high) or too slowly ("lugging" the engine).
A tachometer (sometimes called a tach) is almost a "must-have" gauge for vehicles with a manual transmission; the driver has to manually change gears; the tach helps the driver know when revolutions are in the optimal range.
Some say you don't need a tachometer if you drive a vehicle with an automatic transmission. It's true that most drivers of automatics don't even look at it. But there are times when paying attention to the tach can help you prevent an expensive repair.
Here's a good example. Manufacturers now build many of their automatic transmission vehicles with shift paddles. They let you shift gears without a clutch. That's manual shifting, and drivers need to know they're not revving the engine too high. That's where the tachometer comes in, since it shows you visually when you are in the red zone (RPM too high).
Here's another way the tach can help you: fuel economy. Generally speaking, the lower the RPM, the better the fuel economy. It's not good to go too low, of course, and the tachometer will help you find that spot of maximum efficiency.
You can also spot problems by paying attention to the tach. When your vehicle stays in first gear longer than usual (higher reading on the tach), then the RPM dip lower than usual after shifting, it may be that your vehicle's transmission is skipping a gear. Plus, if your vehicle's RPM go up but your speed doesn't, it could mean your transmission is slipping. Either situation should be checked by a trained technician.
If your commute takes you down some long grades, you might like to put your vehicle in a lower gear to help slow down the car (and not burn up the brakes). Having a tachometer keeps tabs on when your engine is revving too high.
So, consider the tachometer a "bonus" gauge. It's one more helpful assistant that can help you spot and prevent problems in your vehicle.
Need Service?
More articles from Charlie's Fast Lube Jackson

A Most Important Part (Serpentine Belt Replacement)
February 8, 2026
Your vehicles engine is an engineering work of wonder with many complex parts working in harmony to get you down the road. One of those simple but important components is called a serpentine belt. It is driven by a pulley on the engine and transfers that power to many of your engines most importa... More

The New Blade in Town
February 1, 2026
If your windshield wipers are streaking and chattering when you turn them on in the rain or snow, it's time for a little "blade renewal." And when it comes to new wiper blades, there are some new designs that are worth a look. One of the latest is called the beam blade. It's different than conve... More

Light Up your Life (Headlamp Replacement)
January 25, 2026
Did you know that having a burned out headlight can result in your rearview mirror reflecting some flashing lights? In other words, you might get pulled over by the police for only having one working headlight, because in most places it's against the law. Not only is it illegal to drive with one... More
