I’m pretty sure I know what’s going on with my car, but before I take it in and the mechanic shop tries to charge me an arm and leg, I’d like someone else’s input.
My car’s (2004 Hyundai Elantra GLS) check engine light came on awhile ago, so I took it to the local car part store and they put it on a sensor and got a reading of PO442 and PO456. One of the most common causes is a leaky gas cap, so I got a new one and reinstalled the gas cap, cleared the codes, and drove it for a day and to see if the codes come back, which of course, they did. Then a new symptom showed up.
The new symptom? Whenever I put gas in the car for the past few times, there are drips of gas as I am pumping. As soon as I stop adding gas, the leak stops. It drips–not pours. (I’d prefer that it neither drip, nor pour.)
I crawled under the car and couldn’t see anything obvious–nothing like a crack anywhere–so I’m thinking there’s a leak probably close to the entrance of where the cap is.
After extensive consults with The Google and The YouTube, I’m thinking the fuel tank filler neck might need to be replaced. How difficult would that be–is it something a “back yard mechanic” might be able to do? Might there be some way to patch or plug the leak (and if so, any suggestions on what to use)?
The car has over 173K miles on it, and although I’m not in the market to buy a new one, I’m also not in a position to drop several hundreds of dollars into it either. This is keeping me up at nights, so I’d really like some news I can work with here…
you’re barking up the correct tree. both of those codes are evaporative emissions faults, so those combined with the leaks you see when filling up means it’s likely the fuel filler neck is effed up. without knowing how the one on your car is designed, I can’t say what it would take to fix it. It might be a rust-through in the metal filler neck, or one of the rubber joints might have started leaking. Fixing it might entail dropping the gas tank.
I’d say, just from your description, that there is a problem with the vapor recovery system. You might try and google information on the vapor recovery system. My guess is that a reputable mechanic would charge somewhere between $200-$400 to diagnose and fix this. While you aren’t in a position to drop this kind of money into the car, this is less than a typical monthly payment on a new car, so you might want to look at it that way. As it is keeping you up at nights, you probably should find the money and fix it. Worse case, the car catches fire from a gas leak.
By the looks of it, I don’t think the gas tank would need to be dropped to get to fuel filler neck. (However, of course, no local parts store carries the fuel filler neck…I’d have to order it online, and it ain’t cheap.)
Theoretically it’s fairly straightforward on most cars. The possible big challenges would be if the attachment hardware at the top of the filler neck is badly rusted, and if the access to the hose clamp at the bottom of the neck is obscured. I suggest have the tank no more than half full when doing the repair.
You might be able to repair the leak with two part epoxy or something else that will withstand gasoline. The patch area will need to be rust free and clean, which will almost certainly require removing the neck to prepare it properly.
Thanks, Gary. I ordered the repair manual–even though it looked pretty straight forward when I crawled under the car and on what limited videos I can find online, I know it can turn complicated really fast. If it needs to be replaced, I’ll still have to order the part online. I’m hoping not to have to sink a few hundred (or more) into this car, but I do need it running.
Until the leak gets to the point of being a fire hazard this is something you can ignore indefinitely.
The check engine light is there to tell you (in this case) that you’re polluting more than the law allows. That’s the end of the significance for the operation of the car.
If you don’t have the money to get it fixed, quit worrying. Do pay attention when fuelling. If it starts leaking enough that you’re worried about starting a fire that’s the time when ignoring it quits being an option and you need to fix it.
In an ideal world all of us could afford to maintain our pollution control in perfect working order. And we’d all drive vehicles that get good gas mileage. And drive gently. And I want a pony.
In the real world compromises must sometimes be made.
Well, that’s one reason. If it’s a steady-on light, then as you say, there’s an emissions control problem that you may want to get around to fixing some day when you have the time and money to do so. If it’s a flashing light, then there’s a serious problem that could do permanent damage if you continue to drive the car.
When I had a Hyundai I got lots of great advice and DIY tips at this forum: www.hyundai-forums.com. If you’re lucky someone else has already dealt with this and posted about it. The part is out of stock at Rock Auto, so it might be a common issue.
This is a problem with my dad’s Ford Taurus, for what it’s worth. He’s been waiting for his mechanic to find a replacement from a junkyard for quite a while now. The mechanic, like LSLGuy, said it’s nothing to worry about until it’s time for e-check.
Auto parts stores at least used to sell generic bendable fuel filler hose by the foot. Depending on how the vent hoses are arranged, that still might work with a newer car.
I’ve been tempted to buy a funnel to bypass any rusting/hole that’s most likely towards the top while I’m putting gas in the car. Bypass the possible hole, and gas doesn’t leak when I’m adding it, right?
Ought to work. But you’ll be stuck holding the funnel and the dispenser nozzle in place the whole time. You’ll also be dispensing about half-speed or less or else you’re going to be wearing a lot of back-splash.
I hope it’s warm the next few months where you live.
But that doesn’t address the ECM code, or your fuel losses to evaporation. But even so, that’s probably better than leaving a puddle of fuel on the ground every time you gas up.
Or you could keep a gas can in your trunk. Put it under the leak when filling up and soon you’ll have an emergency fuel supply (or a ready supply of gas for the mower/snow blower/generator).
I wanted to post an update, in case anyone comes along in the future, looking for possible solutions. I also wanted to thank everyone for all their suggestions–it was very helpful to get your thoughts and ideas.
My son-in-law came this weekend, and although he’s not a mechanic, he is very mechanically inclined. He pulled off the wheel and we could easily access the fuel filler neck and it’s cover. I’d read on other boards that the cover, while protecting the lines from all the crap kicked up by the tire, can also trap stuff under it (and cause rusting of the line). Sure enough, we pulled that off and out fell tons of debris. We could easily see where the line was rusting, so we took a stiff brush and brushed off the surface. (I was afraid to going too deep with it, as I didn’t want to brush rusted debris further INTO the fuel line.) We then used some epoxy putty that I picked up at the auto parts store (made for things like fuel lines) and covered the entire area (including around the line where it wasn’t rusting to secure it). After letting it set up (it was “set” in about an hour, but we waited several hours), I filled the car with fuel, and no leaks.
I realize it’s not a long term solution, but the car has over 170K miles on it…It cost $4 for the putty, and if it can save me a $160 part (plus the cost of having it installed), then it’s completely worth it to me.
