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Fleet Management 101: How maintenance affects miles per gallon

101_Series_Badge-1.pngWhen we think about fuel economy, our minds tend to go right to the type of vehicle in use. We think about smaller, lighter vehicles, or hybrid electric models. This makes sense, but it doesn’t help our fleet after the deal is done and the vehicle is sitting in the lot.

The good news is no matter what type of fleet you’re managing, there are always ways to save on fuel. That’s because the way vehicles are driven and maintained contributes to miles per gallon. In fact, according to the Department of Energy, fixing a serious maintenance problem, such as a faulty oxygen sensor, can improve mileage by as much as 25%. Ideally, however, you’re performing regular preventative maintenance, which the DOE says will increase fuel mileage by an average of 5%.

Here are some major areas where proper maintenance makes a difference in fuel economy:

New spark plugs

Spark plugs work in an incredibly hostile environment. If a vehicle has more than 30,000 miles on it, change the plugs to fresh ones that aren’t covered in carbon deposits.

Change the air filter

Your engine “breathes” in 14 million gallons of air through the filter every year. On pre-1999 vehicles a dirty air filter increases fuel usage by almost 10%. On newer vehicles, the internal computer is smart enough to detect the lower airflow, so it cuts back on fuel use. This is a great feature for fuel, but not for vehicle performance; when this happens, your engine will lack power and pick-up.

Our tip: check the filter when you change your oil and replace it at regular intervals.

Use proper motor oil

You can improve your gas mileage simply by using the manufacturer's recommended grade of motor oil. For example, using 10W-30 motor oil in an engine designed to use 5W-30 can lower your gas mileage by 1–2%. Thicker oil is more difficult for the engine to pump and therefore requires more fuel.

Replace your oxygen sensor before the light goes on

Oxygen sensors monitor the efficiency of combustion by tracking the amount of oxygen remaining in the exhaust. Over time, these sensors degrade and need to be replaced. Failing to do that on time can cost you up to 15% in gas mileage. On 1996 and newer vehicles, you need to replace these sensors every 100,000 miles.

Check the fuel cap

Vehicles in your fleet are likely equipped with an evaporative emissions control (EVAP) system, which is designed to store and dispose of fuel vapors before they escape. After containing the fumes, the system condenses them into droplets and reintroduces them in the form of fuel back to the engine. If a fuel cap is broken or missing, gas fumes are escaping.

Check the tires(!)

We talked about this in our last blog, but it bears repeating: properly inflated tires improve fuel efficiency. Underinflated tires burn more fuel. If tires are 8 pounds underinflated, which is not an uncommon condition, rolling resistance of the tires increases by 5%, and that robs your vehicles of gas mileage. It’s also important to keep your tires aligned. Misaligned tires drag instead of rolling freely. Improper alignment can reduce fuel efficiency by as much as 10% – about 31 cents per gallon.

If your fleet has already implemented these tips, you’re probably getting the most out of your mileage. Now all you have to do is make sure your drivers are keeping their speed below 60mph, the speed at which fuel efficiency drops significantly.

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