How To Test A Gas Cap For Leaks

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Being able to test a gas cap for leaks is an essential part of taking care of your vehicle. If a gas cap is leaking, the inside of your car will probably smell like gasoline – it will be a strong odor and you will most likely smell it right away. Leaving this issue unfixed will damage your car and it may lead to a serious engine leak. Plus, it will make that gasoline smell nearly impossible to get out. Keep reading to learn how to test a gas cap for leaks so you can avoid this problem with your vehicle.

Step by Step Guide On How To Test A Gas Cap For Leaks

1. Problems Tightening the Cap

Gates 31838 Fuel Tank Cap

If you are struggling to tighten your gas cap, that is most likely a sign of a broken gas cap. The cap will usually click into place when you attempt to tighten it, and if you don’t’ hear that click, it is most likely broken. In this case, you will need to replace the gas cap right away before a bigger problem occurs. 

2. Strange Coloration Around Your Gas Tank Mouth

If you notice any strange coloration at the gas tank mouth, that is a sure sign you may have a gas cap leak. This may not be something you would notice offhand, which is why this sign is most commonly ignored at first. 

3. Foul Gasoline Smell While Driving

A foul gasoline smell while driving is the most common sign of a leaking gas cap. Most people notice this right away because of how strong the smell is. If you notice a strong gasoline smell in your car, you should not continue to drive around for a long period of time. If possible, drive home or stop somewhere close by. The longer you leave this problem unsolved, the more likely you are to experience engine damage to your vehicle. It is essential to pay attention to your vehicle and to maintain it so that way it lasts for a long time. If you take care of your car, you will avoid paying heavy repair costs. 

4. The Check Engine Light Comes On

When the check engine light comes on, it could mean a variety of things. There are many car problems that occur that can spark the check engine light to come on, and a leaking gas cap is one of them. Of course, when the check engine light comes on, you may not be sure what the problem is. If you experience a strong gasoline smell around the time the check engine light comes on, then that is a sure sign you have a leaking gas cap. If you do not notice a smell, be sure to check for a leaking gas cap anyway. It is always better to be safe than sorry when it comes to your vehicle. 

5. Poor Fuel Economy

If you notice that you are using up an excessive amount of gas to go to nearby places, that is a sign that you have a leaking gas cap. There is most likely a trickle of gas leaking from your vehicle as you’re driving. If you notice this happening, you should stop driving immediately. If that much gas is leaking from your car, that is a safety risk and should not be ignored. 

6. Evaporative Emission Control System (EVAP) Self-Test

Modern vehicles have an automotive diagnostic system known as OBD-II (on-board diagnostics). This system monitors a number of engine and emissions-related components. The system ensures that everything in your vehicle is in working order. The (EVAP) can detect fuel vapor leaks, that allow gasoline fumes to escape from the gas tank and EVAP system. A large leak such as that caused by a loose or missing gas cap will set either a code P0455 (large leak) or a code P0457 (loose gas cap). Small pinhole-sized leaks will set a different code, and it will usually be P0456 (small leak).

Related Codes:

Final Thoughts 

Taking care of your vehicle is essential to your safety and your vehicle’s longevity. If there is something wrong with your vehicle, it could be a potential safety risk for both you and your passengers, so make sure you pay close attention to your car as you drive it. If you do notice a gasoline smell or your check engine light goes on, you should stop driving as soon as possible. If you cannot fix the problem on your own, you should bring your vehicle to a mechanic you trust so inspect it. Remember that it is always better to take care of the problem right away than to leave it unsolved.

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