Follow-up on can't fillup


So the new to me '02 Sonata spent the day at the dealership to try to diagnose the difficulty with the gas tank that prevents gas fill ups. It seems like the car has had work done on the Valve Assembly-Fill Vent and the filler tube is also new. The diagnosis for now is that the Overfill Valve is stuck closed and needs to be replaced. Parts $5, labor 4hrs, which adds up to ~$500 in this area. Now my understanding from my search on this forum was that when I shove a tube down the filler neck it should have opened this valve, am I not pushing hard enough? Also there is a recall on a valve that prevents gas spillage on rollovers, but my car is not in the same production months and also I am not sure if these are the same valves.

When I learned to work on cars the gas tank was much simpler. This car has left a sour taste, I guess I can buy a gas container and fill my tank through that.


Getting service at a dealership, unless it is for warranty work, pretty much guarantees the highest cost wherever you live. I’d get a second opinion from another shop.


I have been to 5 local shops. They just don’t want to touch this. It seems that the parts are dealer only and they sense headache as far as the fix. This forum is really my second opinion.


I wonder – do you really need an overfill valve? If this is such a troublesome item, can’t you just remove it and throw it away?


I was exactly thinking the same, I guess then the pump will not shut off. I am not sure also what happens when your car rolls over and such. I didn’t put this as an option because, I am sure the dealer would not do this out of fear that they might get sued over something. What kind o a val is this? What should I push down the filler neck to open this “permanently”.


Not certain, but I think the gas pump is unaffected by this valve. The nozzle has its own shutoff mechanism. And I am not too concerned about a rollover, but that’s just me. It won’t hurt to ask a mechanic – there ought not be any liability on his part if he is following customer’s instructions, but he may or may not agree. I still would investigate removal, but it seems as though the same labor is involved in either removal or replacement.


Is the problem that the gas pump auto shut-off immediately kicks when you try to fill up?

This was a somewhat different vehicle, but my '76 Chevy pickup does that exact same thing with some gas pumps, especially ones with the little vapor-capture devices. The solution was just to find a gas station with an old-style nozzle. This might be a problem if you’re in California, but I found even with the eco-friendly nozzles, if I didn’t put the pump in quite all the way, leaving a little air gap, I could usually fill up if I held it in place and on half-flow and was very careful not to overfill it. It’s a pain in the butt, but it might be worth it to avoid paying for this repair.


I can only find a manual for a 2000 Accent, but from my reading of it, I believe that this valve isn’t located in the filler neck, but rather between the gas tank and the evaporative emissions control devices. I believe it regulates the airflow to the Evap system during a fill up so the pump shuts off at the right time, as opposed to physically blocking the filler. Simply judging by the fact that it’s a 5 dollar part, but a 500 dollar labor charge, I would presume that this part is probably not going to be any easier to remove than to replace. I would guess it might involve removing the gas tank.


Well yes we happen to be in CA. I have not found a gas station without the fancy nozzle. The filler neck is kind of long so you end up advancing the nozzle some to just make it pump. I have to press the handle to a level less than the slowest speed on the pump handle and still would shot off 15-20 times per fill-up. I have not been able to get the tank to more than 3/4 full and have to go to the stations at late night otherwise people get annoyed by me standing there forever. I just want to be sure that this $500 will resolve the issue.


JUst took a look at my 02 Sonata shop manual & cant find anything on an “overflow valve”. Are you sure thats what the dealer called it?

You might want to go to & signup for an account.

Then go to the detailed drawing of the fuel vent system on page EC-14 of the service manual. It shows exactly how it’s plumbed. It also makes me glad my daily driver is an 87 Ranger.

Page FL-115 is also worth a look.


So the new to me '02 Sonata spent the day at the dealership

Dealers are no better (or worse) than independent mechanics for almost anything you might need done on your car.  They will almost always charge more per hour and often more for parts and supplies.  They also tend to look at repairs a little different than the independent. 

A dealer may well recommend work that strictly may not be needed, but could be connected to the problem or maybe replace a part when a little repair would fix it ALMOST as good a new.  

There is no need to bring your car to the dealer for any service other than service that is going to be paid for by a recall or original warrantee.  During the warranty period be sure to have all required (as listed in the owner's manual) maintenance done and to document all maintenance work.

I suggest that most people would be better off finding a good independent (Not working for a chain) mechanic. 

Note: Never ever use a quick oil change place. They are fast cheap and very very bad.


As I mentioned no local shop was willing to touch the thing. The local shops per hr labor is not much different than the dealer, but I know the dealer would probably charge more. In this case they quoted a flat $55 for the diagnosis which was much better than the open end quotes from reluctant shops.

I have this schematic, the hma site does not work on my new vista PC. My car and PC suddenly decided to go sour together.,2782&groupid=2783&subgroupid=9621&componentid=0&makeid=13&model=Sonata&year=2002&graphicID=1022585&callout=11&catalogid=2&displayCatalogid=0