Q: possible evap charcoal canister

asked by on

By the gas cap there is a black like charcoal substance that looks as if maybe an over flow as well. The cel isnt on nor do i smell gas, not sure if i have over filled gas tank please help
My car has an automatic transmission.

I’ve not heard of charcoal appearing by the filler neck before, but I have seen canisters break up and regurgitate their contents into the connecting hoses, so I suppose its possible that what you are seeing is charcoal from the canister. If you are in the habit of topping off your gas tank, that might be a contributing factor. Many people like to fill their tank all the way up the neck and that can potentially fill the canister with fuel. The canister is designed for fuel vapor and is not built to be full of liquid gas. From now on, when you fill the tank, just run it until the pump shuts off, and don’t continue to pull the trigger. That leaves enough airspace in the tank for the fuel to expand when it’s hot without flowing up into the lines and canister. If you’re not experiencing any other symptoms, it probably won’t cause any other problems, but if you smell fuel or see puddles, you should contact YourMechanic and get them to send a technician out to look things over.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. possible evap charcoal canister

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My AC bearings are making noise - what does this mean?

Hi there. I am not quite clear which bearings or other components you may be hearing. The most likely noises coming from the engine compartment would be the AC compressor clutch bearing, and the compressor itself. While the clutch bearing...

Q: Have oil in the intercooler and the motor has no power 2004 VW Jetta Turbo-diesel

Hi - I suspect the [turbocharger oil seals have blown out](https://www.yourmechanic.com/question/turbocharger-leaking-oil, and are leaking oil into the air intake/intercooler piping. This is also reducing turbocharger efficiency, and power generation. I recommend a loss of power inspection performed by a mobile,...

Q: Will a very small crack in my intake manifold cause major damage if I wait about 3 months to fix it?

Unfortunately, there is no way to tell how long the crack will last without getting worse as many things can affect the progression of something like this such as heat, excessive warming up and cooling down and how long the...

Related articles

What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.