Topping off can also cause harm to the charcoal canister of the onboard refueling vapor recovery (ORVR) system in your car. Consumer Reports points out that “adding more fuel after the gas pump clicks off can damage the charcoal canister by saturating it with fuel and cause the check engine light to illuminate. If the ORVR is damaged, it won’t adequately capture those harmful vapors.”**
*EPA, June 26, 2004, “Don’t Top off Your Gas Tank -- Save Money at the Gas Pump and Help Protect the Environment”,
https://www.epa.gov/archive/epapages/newsroom_archive/newsreleases/714cf2672631269e852570d60070fe91.htmlwww.epa.gov
**Devin Pratt, November 13, 2021, “Should You Top Off Your Car’s Gas Tank?,” Consumer Reports.org https://www.consumerreports.org/car-maintenance/should-you-top-off-your-cars-gas-tank-a1176503026/
Photo by Mike Mozart, Flickr Commons