You may not have even thought about what happens when the charcoal canister in your vehicle fails. This is likely because the charcoal canister is one of the most reliable components of a car!
However, if a charcoal canister (EVAP canister) fails, you’ll experience bad fuel economy, hard starting, and increased emissions. Here are the signs of a bad charcoal canister so you can fix it now or pay for a much bigger problem later.
How does a Charcoal Canister work?
In simple terms, the charcoal canister collects excess gasoline vapors and fumes from your gas tank.
The charcoal is activated carbon, designed to have a lot of pores to help absorb as much gas and other toxins as possible.
If the charcoal canister was not present, the vapor would either pool in the gas tank or be purged from the car, into the atmosphere, and often be dangerously toxic for the environment.
Since the canister collects the vapor and uses it to help power the engine, the EVAP system helps improve the efficiency of cars for the environment.
Charcoal canisters are generally self-sustaining because their construction is a relatively simple device.
There may be instances where damage occurs or wear and tear causes a malfunction. The most common charcoal canister problems are caused by “topping off” your gas tank and causing a fuel flood in the canister.
Symptoms of a Bad Charcoal Canister
#1. Check Engine Light.
Your car’s computer could be aware that there is an issue with your car’s charcoal canister before you are. Since this car part operates on its own, this is not likely to be the first item the mechanic looks for when diagnosing a check engine light.
Of course, don’t forget the extra symptoms of a failing charcoal canister so you can properly determine the cause of your automotive problems.
#2. Have Failed Your Emissions Test.
If you see that your car’s emissions have significantly increased, it might be due to a charcoal canister malfunction. The main function of the EVAP system is to help prevent over-releasing gasoline vapors into the environment.
You might notice that your car’s engine is running richer or a more pungent fuel smell from the exhaust. Between the check engine light and the excessive emissions of your vehicle, a faulty charcoal canister can cause your car to fail your state-required emissions inspection.
#3. Reduced Vehicle Performance.
Because the EVAP system connects to the engine via the purge valve, problems with the charcoal canister can yield problems with your car’s performance. If this system is acting up, the purge valve can be stuck open, causing your engine’s air-fuel mix to go bad.
Therefore, you could see a potential decrease in your vehicle’s performance. You might find you are getting fewer miles, possibly trouble starting your car, or a rough idle if your charcoal canister is malfunctioning.
#4. Issues Filling Up Gas Tank.
When a charcoal canister is saturated or the fuel vapor vent line is plugged, one of the first places you may notice an issue is at the gas pump.
You may find you are not able to fill your tank, or that the gas pump nozzle shuts off before your tank is full. If the charcoal canister is unable to remove vapor from the gas tank, those fumes occupy volume, minimizing the volume in your tank to fill.
#5. Fuel Smell in or Around Your Car.
A defective charcoal canister will fail to capture fuel vapors before they escape your powertrain, causing a strong fuel smell around your car.
Sometimes those nasty fumes can accumulate in the cabin, which will be a problem for most drivers. These vapors can be harmful to you if you are exposed for long periods and can make you dizzy, confused, or even cause you to lose consciousness.
Can You Clean a Charcoal Canister?
Some owners may have the industrial means to clean a charcoal canister instead of determining if the canister is faulty or if some of the lines are blocked.
Specifically, you would remove the canister from your vehicle and use an air compressor to blow air through the canister at an appropriate level of psi to clean the canister without damaging internal components.
Check your vehicle’s emissions manual (if you have one) for further information on how to clean a charcoal canister. Also, never pour any liquids into the canister, as this will damage this piece permanently.
In general, it is not recommended to clean a canister, and replacement should be performed instead.
Charcoal Canister Replacement Cost
The cost for a charcoal canister replacement can set you back anywhere from $150 to $630. Generally, a new part will cost about $100 to $500, depending on your vehicle’s make, model. If having a mechanic perform the replacement, labor would generally run an additional $50 to $130.
Accessing the charcoal canisters is generally pretty easy, but working in the EVAP systems can be tricky, so make sure to read your vehicle’s manual on how to make this kind of repair.
Is it Safe to Drive With a Bad EVAP Canister?
Generally, driving with a bad charcoal canister is safe to do in most scenarios. The main concern most vehicle owners will have with a bad EVAP system is that their vehicle will produce considerably more fumes than it did before.
If you are a vehicle owner concerned about your carbon footprint, this may be a good motivator to replace your charcoal canister as soon as you are able, but even still, even if you sit on the other side of the debate regarding climate change, repairing and replacing the canister should be something to put on your agenda.
If your bad charcoal canister creates a strong fuel smell in the passenger compartment of your vehicle, you will want to prioritize this repair.
As we have already mentioned, being exposed to fuel vapors can be very dangerous. If you must drive, roll down a couple of windows to let fresh air into the vehicle.