This article is for all of you out there that HAVE to get to an even number, the nearest dollar, etc. when gassing up your car. The question is, is this really good for your car??? Well, the short answer is NO! Many of the last drops of gas are managed by your vehicle’s Evaporative Emissions System or evap system for short. If the system senses vapors, it will hold them in a canister. When you overfill your tank, this is where those extra vapors go.
The extra gas vapors go into the charcoal canister. The vapors are then pumped back into the engine and burned. Liquid fuel can make the charcoal in the canister break apart. When the charcoal breaks apart it gets pumped back into the engine. The charcoal being pumped back into the engine is not the issue, the issue is the damage done to the canister and the control valve.
Eventually, the control valve will get clogged with charcoal which will cause the “check engine” light to come on. If the control valve gets damaged beyond repair, the consumer will have to replace the control valve, a
nd flush the engine to get all the remaining charcoal out of the system.
Now ask yourself, was it really worth adding that last little bit into the engine????