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Use promotional code MMJ30 at checkout to receive 30% off the following categories: Select Brake Parts, Select Hi-Performance and Truck Accessories, Batteries, Paint, Splash Guards, Select Ventvisors & Bug Shields, Springs & Spacers, Water Pumps, Belts, A/C Parts, Starters, Alternators, Fuel Pumps, Radiators, Radiator Fans, Thermostats, Caps & Clamps, Clutches, Spark Plugs, Plug Wires, CV Axles, Battery Chargers & Booster Cables, OE Locks, Rack & Pinons, Window Motors, RainX Wipers, Appearance Chemicals, Floor Mats, Lift Equipment, Hand Tools, Travel Accessories, Car Covers, Seat Covers, Wheel Covers, Body Repair, Collectibles and Apparel.

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Offers not valid in combination with any other discounts, promotions or items already on sale. Not valid on gift cards, special orders, installed merchandise, commercial or fleet purchases. Those products that are included in these offers will be displayed in product search results and product detail pages. Excludes the following brands: WeatherTech, Champion, Powerstop, Razor, Traxxas, Superchips, Hypertech, Edge, Bully Dog, Diablo, Edelbrock, Holley, NOS, Proform, Specialty Auto, Autometer, Accel, K&N, Kenwood, Pioneer, Sony, Thule, Thule Karrite, JVC, Flowmaster, Hurst, B&M, MSD, Moog, Wagner, Philips and BBK Performance. Valid online until 11:59 PM EST on 11/22/17.

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Gauges 101 | Tachometer | Pep Boys


A car’s dashboard tells you everything you need to know

Gauges 101

The gauges on your vehicle’s dashboard help to disclose the relative health of your vehicle and indicate how well it’s operating. Most gauges measure self-explanatory diagnostics, while others quantify more obscure aspects of the vehicles condition. Gauges have progressed from mechanical to electronic. Some of their messaging is easier to comprehend than others and their functions will diverge from vehicle to vehicle. At Pep Boys we have assembled a directory explaining the various dashboard gauges to help alleviate confusion and assure a long-lasting, healthy ride.


The speedometer measures a vehicle’s speed

The speedometer is the most recognizable of the gauges. It measures the speed the vehicle is traveling in both miles per hour (mph) and kilometers per hour (km/h). The speedometer reading is a reasonably accurate account of the speed the vehicle is operating at that precise moment. In modern automobiles, the speed is measured from an electronic sensor that transfers the wheel rotation rate directly to the speedometer, which displays the findings of that reading in mph or km/h on the dashboard. The driver must continually monitor the speedometer to ensure that they are operating near the speed limit.

Fuel Gauge

The fuel gauge keeps you notified of fuel levels

The fuel gauge indicates the current amount of fuel left in your tank. When the fuel reaches extremely low levels, a warning sign in the shape of a gas pump will appear on the dashboard alerting the driver that fuel is needed immediately. While differing from each make and model of car, the fuel gauge is a not a barometer of the actual amount of fuel left in the fuel tank. The driver should not continually allow the fuel to reach dangerously low levels before refueling. This is because the fuel pump is immersed in fuel and the gasoline acts as a coolant for the pump. When the fuel becomes low, the pump will become exposed to air and can overheat, leading to potential fuel pump failure. This is why the fuel gauge needs to be constantly monitored.


A tachometer measures the speed the engine is rotating

This gauge calculates the speed that the engine is rotating during operation. The tachometer measures how quickly the engine is spinning in revolutions per minute (RPM). If the gauge reaches the dangerously high levels, typically indicated in red, the engine is rotating at a high velocity that can result in vehicle complications. The tachometer should be monitored as it is related to both power output and fuel economy. Generally, the higher the RPM reading, the higher the fuel consumption and power the engine is outputting. Lower consistent RPM levels on the tachometer indicate that the engine is operating at an optimal level resulting in enhanced fuel mileage.

Temperature Gauge/Lamp

A temperature gauge monitors the engine temp, alerting you if it gets too high

Some dashboards include a temperature gauge, while others will display a warning light in the shape of a thermometer to indicate dangerously high engine temperature. The gauge measures the engine coolant temperature. If the coolant temperature warning light appears or the temperature gauge reaches red levels, this indicates that the coolant temperature has reached an extremely high temperature. If you continue to operate the vehicle while these warnings are engaged, the engine can be damaged extensively. Stop the car to attempt to cool the engine. If this does not alleviate the issue then the vehicle will need to be serviced by a professional.

Oil Pressure Gauge/Lamp

The oil pressure gauge lets you know the oil level is low

Another gauge type typically found in older cars is an oil pressure gauge or lamp. Not all dashboards will contain an oil pressure gauge, newer vehicles just have an oil warning lamp to caution the driver that the oil level is low. Oil pressure is vital to your engines performance. Oil surges throughout the engine to lubricate the necessary engine components and keep your vehicle operating. An absence of oil will result in severe engine failure. The gauge measures oil pressure in pounds per square inch (PSI). If the gauge reaches dangerously low or the oil lamp appears on the dashboard, the vehicle will need to be taken to the nearest Pep Boys for service.

Bring your vehicle to the nearest Pep Boys if experiencing any issues or indications with your dashboard gauges. Our team will perform a diagnostic check and determine if your vehicle will need scheduled maintenance.