How to Vent a Gas Tank on a Car

Gas tanks are an important part of a car that keeps it running. However, they also have to be vented from time to time for safety reasons. Keeping your gas tank ventilated is just as important as checking the air in your tires and oil levels. This post will cover how to vent a gas tank on a car properly so you can get back on the road again!

The first step is to use a vent kit. These kits are available at most auto parts stores and usually come with various-sized hoses that fit the specific type of gas tank filler neck and a can of compressed air or an air compressor. Before purchasing your kit, you will need to know which size hose you need. We have mentioned some steps below so you can take them if you need to do them yourself.

How to Vent a Gas Tank on a Car

8 Common Gas Tank Vent Problems:

Here are some of the most common reasons why people have trouble with their gas tanks.

1. Your gas tank has rusted to the point that it is beyond repair.

2. You are trying to install a second fuel level sensor or purge valve in your car.

3. You are refilling your gas tank but can’t eliminate the vacuum.

4. You can smell gas fumes but don’t see any leaks.

5. Your car starts and runs fine, but you have no fuel pressure at higher RPMs.

6. There is a constant drop in fuel pressure as your engine gets warmer, and the problem goes away after it has been running for a while.

7. You have replaced the fuel pump, and the problem continues.

8. Your gas tank has been replaced, and it’s still not holding gas/fuel pressure.

5 Gas Tank Vent Solutions: How to Vent a Gas Tank on a Car 

Many people get confused when trying to figure out what is causing their issues with their fuel tank venting. A few things can cause this, and we will review some of the most common in today’s article.

1. The Actuator:  

When you say your gas cap won’t open, my first guess is normally to check if the actuator moves at all. If it moves, the problem is just the piston/vent assembly inside the tank. If you can move it up and down, but it’s still not opening, then the issue could be either the actuator itself or, at times, some hoses run through your gas tank that can get pinched, which will prevent it from venting because of pressure build-up.

Some Hoses Run Through Your Gas Tank

2. The Vent Assembly:  

This fairly common issue can be fixed by replacing your old vent assembly with a new one from your local parts store. I recommend CARiD because they carry all of the best brands and the customer service is the best in the industry.

3. The Gas Cap: 

If you have a check engine light on from the computer telling you that your gas cap is loose, then it’s time to replace it! There are two different types of caps, one will need to be replaced every so often, and the other would be a lifetime replacement, but the cost to do it is around $50.

4. Loose Fuel Filler Neck: 

This can be a hazardous issue if not handled correctly, so please consult a professional or call your local dealership for some help if you have any issues with this point. This one is pretty self-explanatory; tighten the two bolts on the filler neck and replace the gasket if it is damaged.

5. Fuel Tank Pressure Sensor: 

This one can be a little confusing because you might not even know that your car has one of these, but your car most likely does. They are normally located at the top right-hand corner of your gas tank with a black plug that looks like a black rectangle with two thin white lines running vertically.

It Might Be Difficult to Figure Out the Problem

If you have an issue here, it might be difficult to figure out the problem, but if you look at your gas cap and notice that two small pins are going through it, this sensor will fit in the hole where those pins holes are located.

You Can Check It Out To Bypass Flammable Vapor Sensor

Five Gas Tank Venting System and Methods:

1. Isolate the vehicle’s fuel system by shutting off the fuel supply and ignition switch, opening the appropriate compartment(s) to expose the tank, then disconnecting any auxiliary components that connect it to the engine (such as vapor recovery hoses).

2. Locate your gas tank filler neck, which is usually located on one side of your trunk or underneath the gas tank door.

3. Extend a piece of tubing from your kit’s smallest fitting to the open end of the filler neck as far as it will go, then clamp it in place with a setscrew or crimp-style hose clamp.  

4. Use an air compressor to pump enough air into the gas tank to force out whatever gasoline remains in the filler neck.

5. Unclamp and remove your tubing before closing up your kit’s storage compartment, then close up the fuel tank door or any other compartments opened during this process.  

As a safety measure, you should never attempt to open a car’s fuel tank while the engine is running. When working on your vehicle, always wear safety goggles, gloves, and work clothes if exposed to gasoline or another flammable liquid. Use a tarp or other cover at the end of the job to clean up any spills that could damage your car’s paint job.

 Open a Car's Fuel Tank

Final Words:

The steps outlined in the blog post on how to vent a gas tank on a car are easy to follow and should help you vent your gas tank on a car without any problems. Remember never to use anything but a vacuum cleaner when doing so because any other device could cause sparks that might ignite fumes inside your vehicle’s gas tank. 

If, at any point, you get stuck or have questions about the process of removing fuel from an automobile, please feel free to contact us for assistance. We’re always happy to lend our expertise when it comes to automotive repair jobs like these!

Check out our article How to a Gas Tank Door From the Outside.

Jennifer Branett
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