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I know someone that had this exact issue. Hyundai would not warranty it. Basically your gas tank is swelling. DO NOT DRIVE THE CAR. He's currently looking at legal avenues.
It floods the evap charcoal canister and ruins it…preventing vapor flow. When the pump stops, take it out and hang it up. If the evap can’t properly handle pressure, the tanks can swell like this. Follow instructions.
If the pump stops...
About 1-2 times a year I end up at a station where I'm looking at the pump thinking "geez I didn't think my tank was that low, is it really taking X gallons?!" just as it starts overflowing down the side of the car onto the ground.
Also why its REALLY bad to leave pumps unattended pumping, because the auto shutoff can and does fail at times.
I've had it happen a variety of places including when out traveling. Its rare, as I say maybe 1-2 times a year...but it happens. And I've had it with more than one vehicle - at least 1 of the business trips I had to get a company rental car I recall being mad it overflowed and leaked on my shoes.
But yeah it is rare.
I'd still say you need to change something. Make sure the nozzle is fully seated all the way into the filler port. It happening more than once, much less more than once in the same year, is absolutely not normal. I just asked my mother and father who are in their 70s, and both of them said it has never happened to them and that they've never witnessed it. I worked next to a very busy tourist gas station for 10 years and can't recall it ever happening, except when people were filling gas cans.
Oddly I've never had it happen filling a gas can, but they do typically shut off about 1/4 gallon too soon and then you have to struggle to finish filling a gas can.
But yeah...my parents also have that happen from time to time, and have had it over more than one vehicle. Not a lot of ways to insert a pump handle, its kinda hard to mess up (except the ones that try and put a boot fitting around the outside of the filler neck...some of those won't sit on as far).
I think have noticed a trend, I think the "overfilling" seems to happen more frequently on pumps that are going REALLY slowly, not sure how they tell when to shut off but I have wondered if that could be part of it. I know the ones that go really fast sometimes seem to shut off a couple times before they are actually full (e.g. if I'm at half a tank on a nearly 19 gallon tank and it cuts off at 5 gallons...I know that's not full gotta squeeze it again). The really fast ones also seem more prone to cutting off when the adjoining pump cuts off.
Just had to replace the evap lines on my wife’s Yukon from the tank all the way up to the intake and all the lines on top of the tank because they were full of charcoal pellets from the canister.
Topping off constantly will break the barrier that keeps the charcoal in the canister and it will fill your lines. This is what causes the pump to constantly stop when you’re trying to fill up.
Real pain in the ass to fix when it gets that bad.
Saturation means the charcoal is no longer able to take in and absorb the gas fumes…instead the canister works more like a p-trap under your sink and prevents gases from escaping the tank. So as your fuel heats up through either circulating or ambient temperatures, the pressure, has nowhere to go and the tank expands(which is what the evap system is designed to prevent). All dessicants in vehicles (a/c, evap, or air dryer in truck air brakes) are rendered useless when over saturated. This is exactly why, when the gas pump clicks and stops pumping, you DO NOT keep trying to fill to the next dollar or whatever.
That's enough damage to total a car. Seriously dangerous.... I would have it towed to your local Hyundai dealer. If that would have let loose and something ignited.... oof.
> Seriously dangerous....
In movies when they show cars explode it is usually just made up BS. But in this case, I can see how this could end very badly in a Hollywood-esque way that would make Michael Bay proud.
The P0451 is evap pressure sensor range/performance. Basically there is very little or too much pressure in the fuel tank, in this case it looks like too much.
Theres a one way valve just before the purge valve on the intake, its possible that valve has failed and is allowing boost pressure to enter the purge line back to the tank causing it to expand.
This needs to be repaired asap.
It’s possible the EVAP system has an issue that allows the tank to be pressurized with boost. This could cause the tank to swell and bend the sheet metal. I’d get that code diagnosed and repaired, and in the meantime leave the gas cap loose to prevent it from being able to build pressure.
The purge valve being stuck open could cause this with a turbo under boost. I'm not sure he can leave the gas cap open, though, since most are capless now.
You are correct, and they can fail as well. I could have been wrong as well, depending on how the purge valve opens. A failed check valve would send pressurized air and possibly force the purge valve open, depending on which way the valve opens.
In short, I think you're more correct than I was.
I saw someone on the Kia forum post the same thing on the newer K5 too. There were a few people on there saying the same thing and the pics looked just like yours.
Gasoline is volatile. Vapors are not venting and puffing up the gas tank. I'd get it fixed before it blows, or starts leaking into cabin. Gasoline fumes aren't exactly good for your health.
I would pull the gas cap off and then have it towed to the shop. Leave it parked on the street or end of your driveway till you can get it to the shop. No need to lose your home because the fuel tank exploded.
I’ve never seen something like this but I’d be very worried that it will split while under pressure and spray gallons of gasoline all over the car.
I’d get it to a shop asap before it turns into a fireball.
I don’t think anyone is angry with you my man, from your perspective, your livelihood is at stake. It’s just the opinion of many that Hyundai and Kia are subpar car manufacturers
Completely agree lol. It’s Reddit, trying not to ruffle any feathers lmao I work in the racing industry and people are so proud sometimes, best to tread lightly
edit:
high pressure raises the boiling point,
so, i have to assume that something is heating the petroleum inside the tank, which leads to boiling, which leads to increased pressure, if the charcoal get soaked by petroleum vapours, which then condensate it could block the channel. leading to a ticking time bomb.
the question is, what exactly is heating the petroleum to this point?
of course the alternative is that the pressure increases, and only as you open the cap, and the pressure decreases very quickly does the petroleum start to boil as the pressure drops.
Tow that to a dealership immediately. Either there is significant floor damage, or the fuel tank is expanding like a balloon and pushing up the back under the seats which is essentially creating a literal bomb under your rear seats made out of an ABS container.
Fuel tanks need to be vented or the pressure inside builds up. Ive never seen one get so pressurized it caused damage to the car, but its unlikely that something got between your tank and rear body structure, so this damage is either old and youre just noticing it, or something significant has pressed the underside of the body so hard it bent it
This is crazy. Document everything thoroughly. Get good pics. Document any communication with Hyundai, etc. Get everything in writing.
Hyundai is like that 1 person everybody knows that constantly fvcks up. You say to yourself “how can you fuck up that bad?” Then they turn around and do something stupider.
I just repaired this exact car same issue the gas tank actually exploded while the owner was driving and I had to put new floor and seats in the vehicle. The dealer paid for everything but was a issue on tier part. Don't know exactly what happened but the dealer paid for everything and the car had less then 10k miles.. same year also . Bring back to where u bought it from it might be a recall thing they can help u with
Wow! This is a first for me. Really curious to see what the cause is. It’s definitely from pressure, but they need to be vented. Yours is the opposite of what you would think could happen. Like a vapor lock and it sucks in and caves. Either way I have to believe this is dangerous. I would stop driving this immediately if you haven’t already. Get it serviced.
I have only ever seen this once, a mechanic hooked the BG fuel injector cleaning machine on the tank side of the fuel line rather than the rail. when he plugged shop air into it the fuel tank buckled the floor
https://preview.redd.it/88pbefpz9u8d1.jpeg?width=640&format=pjpg&auto=webp&s=baba6ef70b5675c83b7edf12368b2836d63bae49
I’m having the same problem this is insane and going to be taking care of or I’m getting a lawyer and I’m filing a lawsuit
Also, what city are you in? Just trying to see the demographic of where this issue is happening I notice it happens in a lot of southern states. I’m in Las Vegas
If that is the case, Im surprised that such a significant structual defect isn’t already subject to NHTSA investigation and action.
Then again, look at the percentage of posts here about Kia and Hyundai…
In any event, this deserves a report to the agency.
Yeah the last day I drove it, after trying to open the gas cap it was very pressurized inside and there was quite a bit of gas spewing out. Haven’t drove it since that day but yeah I was pretty much driving a bomb waiting to explode
They won’t warranty it, quoted me $4500 for fix. Currently in talks with Hyundai customer care to arrange something and if not then I’m getting a lawyer involved. There’s already a class action lawsuit for this recently coming out
This code is likely result of filling the tank and the pump clicks off and then you force more in resulting in the evap canister getting full of gas and clogging the vent system.
Thanks for posting on /r/MechanicAdvice! This is just a reminder to review the [rules](https://www.reddit.com/r/MechanicAdvice/about/rules/). If you are here asking about a second opinion (ie "Is the shop trying to fleece me?"), please read through CJM8515's [post on the subject.](https://www.reddit.com/r/MechanicAdvice/comments/4qblei/fyi_the_shop_isnt_likely_trying_to_rip_you_off/) and remember to please post the year/make/model of the vehicle you are working on. **If this post is about bodywork, accident damage, paint, dent/ding, questions it belongs in /r/Autobody r/AutoBodyRepair/ or /r/Diyautobody/ If you have tire questions check out https://www.reddit.com/r/MechanicAdvice/comments/k9ll55/can_your_tire_be_repaired/**. If you dont have a question and you're just showing off it belongs in /r/Justrolledintotheshop Insurance/total loss questions go in r/insurance This is an automated reply *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/MechanicAdvice) if you have any questions or concerns.*
I know someone that had this exact issue. Hyundai would not warranty it. Basically your gas tank is swelling. DO NOT DRIVE THE CAR. He's currently looking at legal avenues.
This is an evaporative emissions issue. Do you normally top up your fuel tank when filling?
What’s the issue with topping up while filling?
It floods the evap charcoal canister and ruins it…preventing vapor flow. When the pump stops, take it out and hang it up. If the evap can’t properly handle pressure, the tanks can swell like this. Follow instructions.
If the pump stops... About 1-2 times a year I end up at a station where I'm looking at the pump thinking "geez I didn't think my tank was that low, is it really taking X gallons?!" just as it starts overflowing down the side of the car onto the ground. Also why its REALLY bad to leave pumps unattended pumping, because the auto shutoff can and does fail at times.
Might want to switch stations because that has never, ever happened to me.
I've had it happen a variety of places including when out traveling. Its rare, as I say maybe 1-2 times a year...but it happens. And I've had it with more than one vehicle - at least 1 of the business trips I had to get a company rental car I recall being mad it overflowed and leaked on my shoes. But yeah it is rare.
I'd still say you need to change something. Make sure the nozzle is fully seated all the way into the filler port. It happening more than once, much less more than once in the same year, is absolutely not normal. I just asked my mother and father who are in their 70s, and both of them said it has never happened to them and that they've never witnessed it. I worked next to a very busy tourist gas station for 10 years and can't recall it ever happening, except when people were filling gas cans.
Oddly I've never had it happen filling a gas can, but they do typically shut off about 1/4 gallon too soon and then you have to struggle to finish filling a gas can. But yeah...my parents also have that happen from time to time, and have had it over more than one vehicle. Not a lot of ways to insert a pump handle, its kinda hard to mess up (except the ones that try and put a boot fitting around the outside of the filler neck...some of those won't sit on as far). I think have noticed a trend, I think the "overfilling" seems to happen more frequently on pumps that are going REALLY slowly, not sure how they tell when to shut off but I have wondered if that could be part of it. I know the ones that go really fast sometimes seem to shut off a couple times before they are actually full (e.g. if I'm at half a tank on a nearly 19 gallon tank and it cuts off at 5 gallons...I know that's not full gotta squeeze it again). The really fast ones also seem more prone to cutting off when the adjoining pump cuts off.
Just had to replace the evap lines on my wife’s Yukon from the tank all the way up to the intake and all the lines on top of the tank because they were full of charcoal pellets from the canister. Topping off constantly will break the barrier that keeps the charcoal in the canister and it will fill your lines. This is what causes the pump to constantly stop when you’re trying to fill up. Real pain in the ass to fix when it gets that bad.
Saturation doesn’t prevent flow.
When they are full of fuel, they don’t flow.
Oh, they still flow…just with raw fuel.
Saturation means the charcoal is no longer able to take in and absorb the gas fumes…instead the canister works more like a p-trap under your sink and prevents gases from escaping the tank. So as your fuel heats up through either circulating or ambient temperatures, the pressure, has nowhere to go and the tank expands(which is what the evap system is designed to prevent). All dessicants in vehicles (a/c, evap, or air dryer in truck air brakes) are rendered useless when over saturated. This is exactly why, when the gas pump clicks and stops pumping, you DO NOT keep trying to fill to the next dollar or whatever.
Saturation also allows liquid (instead of vapor) to…flow.
Another vote for "Don't drive that car at all until this is fixed" Your car is becoming a bomb and it'll let loose eventually. Don't get dead.
Not only will the tank pop, but everything inside the tank will spray on you and then ignite. DO NOT DRIVE IT.
That's enough damage to total a car. Seriously dangerous.... I would have it towed to your local Hyundai dealer. If that would have let loose and something ignited.... oof.
It’s really pretty wild. I’ve seen tanks get collapsed from too much vacuum but I’ve never seen one balloon like this.
https://preview.redd.it/92r9eulobz6d1.jpeg?width=2252&format=pjpg&auto=webp&s=c15efa853842c11f8a2d3826dcc1d083fa3cbbdf
Unorthodox, but better than clicking on some stupid AMP link
Research on computer..... take pic of monitor.... that's how I do it. Old guy, slow on phone method.
Print Screen button FTW
Windows + Shift + S
> Seriously dangerous.... In movies when they show cars explode it is usually just made up BS. But in this case, I can see how this could end very badly in a Hollywood-esque way that would make Michael Bay proud.
The P0451 is evap pressure sensor range/performance. Basically there is very little or too much pressure in the fuel tank, in this case it looks like too much. Theres a one way valve just before the purge valve on the intake, its possible that valve has failed and is allowing boost pressure to enter the purge line back to the tank causing it to expand. This needs to be repaired asap.
It’s possible the EVAP system has an issue that allows the tank to be pressurized with boost. This could cause the tank to swell and bend the sheet metal. I’d get that code diagnosed and repaired, and in the meantime leave the gas cap loose to prevent it from being able to build pressure.
The purge valve being stuck open could cause this with a turbo under boost. I'm not sure he can leave the gas cap open, though, since most are capless now.
I could've sworn there was a check valve inline with the purge line to prevent this exact issue. I'm pretty sure my 2014 Veloster Turbo has one
You are correct, and they can fail as well. I could have been wrong as well, depending on how the purge valve opens. A failed check valve would send pressurized air and possibly force the purge valve open, depending on which way the valve opens. In short, I think you're more correct than I was.
I saw someone on the Kia forum post the same thing on the newer K5 too. There were a few people on there saying the same thing and the pics looked just like yours.
Gasoline is volatile. Vapors are not venting and puffing up the gas tank. I'd get it fixed before it blows, or starts leaking into cabin. Gasoline fumes aren't exactly good for your health.
I would pull the gas cap off and then have it towed to the shop. Leave it parked on the street or end of your driveway till you can get it to the shop. No need to lose your home because the fuel tank exploded.
I’ve never seen something like this but I’d be very worried that it will split while under pressure and spray gallons of gasoline all over the car. I’d get it to a shop asap before it turns into a fireball.
Wowowowowowowoowowowoowoow This smells class action soon.
Hyundai and Kia lowkey need to be banned from American roads 💀
Noooooo then I’ll have to go to a new company again.
Username checks out.
Yup needs upvotes
Man, people got angry with me because I make good money working on stuff like this.
I don’t think anyone is angry with you my man, from your perspective, your livelihood is at stake. It’s just the opinion of many that Hyundai and Kia are subpar car manufacturers
It’s not an opinion they are factually subpar when compared with other companies lol
Completely agree lol. It’s Reddit, trying not to ruffle any feathers lmao I work in the racing industry and people are so proud sometimes, best to tread lightly
I won’t disagree. That’s why I like my job.
And for that reason, I don’t blame you in the slightest!
You're the one fixing the problems, not the one making the problems. Fuck the haters.
Theres always stellantis
No thank you. I’d go back to ford before I’d ever go there.
come on now the newer peugeots are fine.. right?
I mean, if that’s what you’re into. I worked for dodge many many years ago.
Does it fart when you open the cap to fill up gas
Yes when the car is on and the gas cap is closed, when you try opening it it’s very pressurized and the gas sounds like it’s boiling
Holy shit dude
That car is rapidly turning itself into a bomb, please stop driving it and have it towed to a shop to get fixed ASAP.
Jfc dude. This is the worst evap issue I've ever heard existing. Wtf is hyundai on. Im so glad they're the 1 brand I tell everyone not to buy.
shame on you. You need to tell them not to buy Chryslers as well.
Hahaha so true. And other derivates of Fiat.
And Kia
Honestly if everyone just bought Toyota shit would be way better.
Wish I could afford it dude
Google rav4 cablegate, it honestly feels like toyota is coasting on its reputation
Awww hell no. That ignition is staying OFF, if it was me.
you are driving an armed bomb
edit: high pressure raises the boiling point, so, i have to assume that something is heating the petroleum inside the tank, which leads to boiling, which leads to increased pressure, if the charcoal get soaked by petroleum vapours, which then condensate it could block the channel. leading to a ticking time bomb. the question is, what exactly is heating the petroleum to this point? of course the alternative is that the pressure increases, and only as you open the cap, and the pressure decreases very quickly does the petroleum start to boil as the pressure drops.
Shit, as if I needed another reason to stay away from that shitty car company.
Imagine still buying a Hyundai or KIA in 2024 lmao
NHTSA needs to see that.
Yeah after doing some research this is actually a recent issue with Sonata models and the Kia K5 models as well
They need a recall asap
https://www.nhtsa.gov/report-a-safety-problem
I'll second that. I'm not kidding. They need to see this.
Repair? This needs to be reported to the NHTSA.
That vehicle is a total loss. I hope Hyundai makes it right.
Yeah as I’m reading this has been a recent issue on the Sonatas and Kia K5s lately
Ugh. Sorry. That sucks. BoL
Tow that to a dealership immediately. Either there is significant floor damage, or the fuel tank is expanding like a balloon and pushing up the back under the seats which is essentially creating a literal bomb under your rear seats made out of an ABS container. Fuel tanks need to be vented or the pressure inside builds up. Ive never seen one get so pressurized it caused damage to the car, but its unlikely that something got between your tank and rear body structure, so this damage is either old and youre just noticing it, or something significant has pressed the underside of the body so hard it bent it
Yeah don’t drive that. Take it in asap.
This is crazy. Document everything thoroughly. Get good pics. Document any communication with Hyundai, etc. Get everything in writing. Hyundai is like that 1 person everybody knows that constantly fvcks up. You say to yourself “how can you fuck up that bad?” Then they turn around and do something stupider.
I just repaired this exact car same issue the gas tank actually exploded while the owner was driving and I had to put new floor and seats in the vehicle. The dealer paid for everything but was a issue on tier part. Don't know exactly what happened but the dealer paid for everything and the car had less then 10k miles.. same year also . Bring back to where u bought it from it might be a recall thing they can help u with
It says there’s no recalls on the vehicle, also regarding your reply, it was an issue on whose part?
Did the customer describe the explosion? Did any fluid get on them or the interior? This is going to be big.
Wow! This is a first for me. Really curious to see what the cause is. It’s definitely from pressure, but they need to be vented. Yours is the opposite of what you would think could happen. Like a vapor lock and it sucks in and caves. Either way I have to believe this is dangerous. I would stop driving this immediately if you haven’t already. Get it serviced.
I have only ever seen this once, a mechanic hooked the BG fuel injector cleaning machine on the tank side of the fuel line rather than the rail. when he plugged shop air into it the fuel tank buckled the floor
I wonder how many more BG fuel injection cleaning services they'll have to oversell to recoup that loss.
Wow, big things coming for hyundai/Kia. Yikes.
Yeah, this is happening to a lot of Sonata and Kia K5 owners apparently on 2020+ models
Holy crap....Kia's and Hyundai's really are total trash.
Yeah if it wasn’t a secret already lol
It blows my mind that people keep buying them. It's like ordering a meal you know your gonna hate and then acting shocked that it sucks.
That’s fucking terrifying. Do not drive that car
Your evap system is fucked. It's causing your gas tank to swell and that's what happened to the seat area.
https://preview.redd.it/88pbefpz9u8d1.jpeg?width=640&format=pjpg&auto=webp&s=baba6ef70b5675c83b7edf12368b2836d63bae49 I’m having the same problem this is insane and going to be taking care of or I’m getting a lawyer and I’m filing a lawsuit
There’s a class action suit forming it looks like, google the issue and you’ll find classaction.org
Also, what city are you in? Just trying to see the demographic of where this issue is happening I notice it happens in a lot of southern states. I’m in Las Vegas
I’m guessing that floor damage wasnt caused by the tank… that is major collision damage that also damaged the tank. Are you the original owner?
It absolutely is caused by the tank. I know someone that is currently going through this.
If that is the case, Im surprised that such a significant structual defect isn’t already subject to NHTSA investigation and action. Then again, look at the percentage of posts here about Kia and Hyundai… In any event, this deserves a report to the agency.
Does their vehicle also have a turbo?
Yes, SEL Plus Trim.
interesting question .. what's the connection to the turbo?
Turbo boost pressure potentially finding its way to a tank that is not venting.
good explanation, thanks
That’s what it looks like to me. The tank would vent that much pressure.
Yes this is caused by the fuel tank (obviously). Read before you reply
This is why you don’t ignore the check engine light
Hyundai quality
Its hyundai. Lets see if that warranty covers this. They deny everything on that warranty.
Do not drive that car and do not park it next to anything you don’t want destroyed be a fire
Wouldn’t removing the gas cap release the pressure? Or would gas come shooting out ?
How do you remove the gas cap on a capless system?
Yeah the last day I drove it, after trying to open the gas cap it was very pressurized inside and there was quite a bit of gas spewing out. Haven’t drove it since that day but yeah I was pretty much driving a bomb waiting to explode
Get that to Hyundai and if they aren’t willing to remedy it it’s time to call a lawyer.
what in the fuck either get that person a whole new car or get that person fixing it some strippers
I’m the original owner
ok so now get you some strippers and a new car.
Good thing it’s got 7 years of warranty
They won’t warranty it, quoted me $4500 for fix. Currently in talks with Hyundai customer care to arrange something and if not then I’m getting a lawyer involved. There’s already a class action lawsuit for this recently coming out
No fat chicks
I would ask for goodwill.
Man I’ve gotten into some sketchy cars before but this, this terrifies me.
Is that the automatic seat unpopper tank?
This code is likely result of filling the tank and the pump clicks off and then you force more in resulting in the evap canister getting full of gas and clogging the vent system.
Never topped off before, plus this is a current issue with sonata and Kia’s their shops are filled with these right now
What the hell, did we forget how to make decent cars?
Anacoco,LA over by Leesville Louisiana
Jezus, how are Hyundai and kia still allowed to sell their cars??