When we put gas or other liquids in a tank, sometimes gas can come out of the tank when we don’t expect it.
Gas coming out of the tank can be annoying and not safe. It can make a mess, waste gas, and be dangerous.
Knowing why gas comes out can help us stop it from happening and deal with it better.
Dive in to explore the causes of gas spews out of tank when filling and potential solutions to this issue.
The Gas Spews Out Of Tank When Filling: What Are The Reasons?
Gas spilling out of tank when filling can be caused due to filling too quickly and improperly positioning the fuel nozzle.
Moreover, damaged nozzles or stop valves, air pressure malfunctions, and kinked fuel filler neck hoses are other reasons.
Filling Too Quickly
When fuel is pumped into the tank rapidly, the fuel level rises too fast, creating pressure inside the tank.
The venting system may not be able to handle this sudden increase in pressure, causing excess fuel to spew out of the tank before the automatic shutoff engages.
Filling too quickly can also be the recipe for fuel splashing and foaming, further exacerbating the overflow issue. And you have to take some gas out of the car to address this.
Improperly Positioning The Fuel Nozzle
If the nozzle is not inserted fully into the fuel filler neck, fuel can overflow as it tries to find a path of least resistance.
Some vehicles have a fuel filler neck design that requires a slower filling speed to prevent spills. If you set the nozzle too high, the gas spits out when filling tank.
Holding the nozzle at an incorrect angle also forces fuel to splash back or hit the walls of the filler neck, and spillage occurs before the auto-shutoff activates.
Damaged Nozzles
The gas nozzle contains stop valves that control the fuel flow. If these valves are damaged or worn out, they may fail to close properly, allowing fuel to continue flowing even after the tank is full.
This can result in gas spewing out of the tank and onto the ground or the side of the vehicle.
Gas nozzles can also get damaged during refueling when you mishandle or drop it. Besides, it may wear over time if not regularly inspected, cleaned, or lubricated.
Air Pressure Malfunction
In fuel systems with fuel vapor recovery features, the vapor vent valve and associated components help regulate air pressure inside the tank.
Besides, it helps reduce harmful emissions.
Once these components malfunction or become clogged, they can disrupt the proper venting of air flow and vapor, leading to pressure build-up and gas spitting back out of tank.
Spills and potential safety hazards are on the horizon. Moreover, the pressure build-up may interfere with the auto-shutoff mechanism, preventing it from activating on time.
Kinked Fuel Filler Neck Hose
The fuel filler neck hose is like a tube that connects the place where you put gas into the car (the fuel filler inlet) to the actual gas tank.
As the vehicle gets older, this hose can get bent or damaged, blocking the fuel from flowing smoothly into the tank.
When the rubber hose is kinked or damaged, the fuel can’t go into the tank easily, and it can pile up and overflow.
Moreover, someone trying to siphon fuel from the filler neck may accidentally leave small objects inside the neck.
These objects can get entangled and block the proper flow of fuel during refueling.
Pinched Vapor Vent/Breather Hose
In older cars that don’t have the ORVR system, a breather/ fuel vent hose connects the top of the fuel tank to the filler neck.
It allows air and gas vapor to escape from the tank, making space for incoming fuel during refueling.
However, during vehicle servicing, the mechanic may accidentally pinch the breather hose between other objects.
It can block the escape of air and vapor, preventing the smooth flow of liquid fuel into the tank.
Without proper ventilation, pressure builds up inside the fuel tank, and the gas comes out when pumping.
Park The Car Under The Hot Sun
When you park your vehicle under the hot sun, the temperature inside the fuel tank increases, transforming the gasoline into vapor.
This increase in vapor pressure inside the tank creates back pressure in the filler neck, which is the tube connecting the fuel tank to the gas cap.
When you try to refuel your car under these conditions, the back pressure prevents the smooth flow of fuel into the tank.
As a result, the fuel can overflow, and the gas spills out of tank when filling up.
How To Fix If Gas Spills Out Of The Tank When Filling Up?
Fill Up The Gas Properly
Insert the gas pump nozzle into the fuel filler neck until securely in place.
Besides, avoid overfilling the tank. When the fuel level reaches the tip of the gas nozzle, listen for a change in the fuel filling sound and pitch.
Stop filling when you hear this change to minimize spills.
Check And Replace The Damaged Part If Necessary
Inspect the gas nozzle and fuel filler neck hose for any visible damage or wear. Replace when it’s damaged to ensure smooth fuel flow into the tank.
Inspect the breather hose and the anti-spill back valve for any pinching or blockage. You can ask a mechanic to help you unclog or replace the damaged parts if needed.
FAQs
Gas Keeps Clicking Off When Filling Up – What Is The Reason?
The gas pump keeps clicking off, mainly due to the fuel tank venting system. The nozzle has a safety device that shuts off the fuel flow when the tank is full to prevent spills.
However, if the nozzle clicks off repeatedly when the tank is not full, it’s likely due to air vapors not escaping fast enough.
It causes the nozzle to get covered in gasoline, creating a vacuum and shutting off the flow prematurely. The vent tube may be kinked or obstructed, triggering this issue.
Why Can’t Pump Gas Into The Tank Fast?
The gas tank may not fill quickly due to a saturated charcoal canister, part of the vehicle’s EVAP system.
Over time, the charcoal in the canister can become saturated and less efficient in trapping vapors.
When this happens, the canister may fill up quickly, causing it to become air-locked and preventing the normal fuel flow into the gas tank.
At this point, refueling becomes slower and may require frequent stops as the fuel pump keeps clicking off.
Is It Normal For A Gas Tank To Release Air?
No, it is not normal for a gas tank to release air when you unscrew the gas cap.
There might be a hole or something not working right in the system that controls air and gas vapors in your car.
This can make air out of the gas tank and let gas vapors into the air.
It’s best to have a mechanic check and fix this system to ensure it works correctly and follows the rules for keeping the air clean.
Conclusion
Gas spews out of tank when filling for many reasons. However, It is important to find out why and fix it.
It’s best to fill the tank slowly and put the nozzle right. If it keeps happening, have a mechanic check the car.
Besides, maintaining your car regularly keeps it safe and working well.