Tips for Troubleshooting Poor Gas Mileage in a Car

If you seem to suddenly be filling up at the gas station more often than usual, there are a number of potential causes for this. It’s good to have them investigated, as suddenly getting poor gas mileage usually means a problem under the hood of the car. Getting this repaired as soon as possible can mean not just saving on gas, but also reducing the risk of the problem becoming more serious down the road. Note a few tips for troubleshooting poor gas mileage in a car and then discuss these with a mechanic if they’re outside your area of expertise when it comes to fixing your own vehicle.

1. Wrong oil viscosity

The word viscosity refers to any fluid’s resistance to flow, or its overall thickness. The numbers on an oil canister tell you about its viscosity; the second number you see refers to the viscosity, so an oil rated 10W-30 has less viscosity, or is thinner, than one rated 10W-40. Note that fluids often tend to get thicker in cold weather, so if you’re using an oil that is too thick and you live in a very cold climate, it might not be flowing through your engine very freely. In turn, the pistons and other parts in the engine cannot move as easily so that the engine works harder and your gas mileage suffers. Check your owner’s manual for the recommended oil viscosity rating for your car.

2. Dragging brakes

If the brakes of a car are engaged in any way, the car will need to work harder to move. You may want to check the handbrake and see if it’s engaged slightly even if the dashboard light is not on. If the calipers to your car’s brakes are also engaged slightly, they will pinch the brake pads against the rotors and in turn, the car works harder to move the wheels. The brake pedal may also need readjusting, if it’s slightly depressed and engaging the brakes.

3. Slipping transmission

If the clutch or any other part of a transmission is slipping, your gas mileage usually drops. The engine will lose power before that power reaches the wheels when the transmission slips, so it works harder and burns more fuel. Note if there are other signs of a slipping transmission, such as the engine revving slightly before it jumps forward or in reverse, or a hesitation or grinding when you change gears.

Author: Cory Anderson

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