The Truth About “Topping Off” the Gas Tank

topping off the gas tankSome car owners top off the gas tank to reduce the number of trips to the pump station. Topping off means to continue to add a bit more gasoline even after the nozzle automatically clicks off. By doing this, you fill the fuel tank beyond its fill line. This is actually a bad idea for both your car and the environment.

Why Topping Off the Gas Tank Is a Bad Idea

Most pump nozzles stop the fuel flow once the tank is sufficiently full. However, some car owners bypass this by repeatedly pulling the nozzle slightly back, or by lifting the nozzle out of the filler neck to keep the valve open.

Overfilling the tank causes some of the fuel to enter the carbon filter and charcoal canister, both of which are meant to only hold vapor. This eventually destroys the canister. Replacing this component can cost as much as $1,500 at an auto repair shop. Furthermore, gasoline in the canister leads to poorer fuel mileage and reduced engine performance. This goes for all vehicle makes and models, including hybrid cars.

Overfilling Is Bad for the Environment

Fuel in the charcoal canister reduces the evaporative emission system’s ability to collect and re-burn fuel vapors. This ultimately means vehicles emit more harmful emissions. Gasoline vapors contain benzene, a toxic air pollutant that is also found in cigarettes.

In addition, overfilling may result in spilling some of the gasoline onto the pavement. The liquid eventually vaporizes into the air, contributing to bad ozone days.

We’ll Repair a Broken Evaporative Emissions System

Bring your vehicle to Monroe Foreign Auto Repair in the event that you experience emission troubles. Our auto service will repair the charcoal canister or make other adjustments to reduce the vehicle’s emission output. On your end, please don’t someone who is topping off the gas tank.

Edited by Justin Vorhees

Evaporative Emissions System Repair

Serving customers in Clearview, Duvall, Gold Bar, Index, Lake Stevens, Maltby, Mill Creek, Monroe, Snohomish, Startup, Sultan, Woodinville