Fill Valve Leak

[CNGBiker]

Hey Fellow CNG'ers!

Have you ever had your fill valve leak?

I have twice now and it's got me nervous! I bought my 2001 Crown Vic used and it didn't have a dust cap.. needless to say I've now got one on order!

What happens is when I'm done with a fast fill and remove the hose, the fill valve on my car is hissing and leaking CNG! Nervously, I re-attach and remove the pump's hose a few times. Fortunately, this seems to stop the leak..

Has anyone else had this happen to them? It's got me rattled and afraid of being stuck somewhere.

Should I look into replacing my fill valve? Is it on it's way out, or is this just a case of random dust/debris messing things up?

Thanks!

[Highmarker]

Re: Fill Valve Leak

CNGBiker,

This is quite a common problem with the Chevy Cavaliers. The following thread might have some useful information. There is also another thread link inside that thread.

http://www.cngchat.com/forum/showthread.php?t=2733

[siai47]

Re: Fill Valve Leak

I don't understand why this is a "common" problem with just the Cavalier . The fill nozzle, of course, is the primary check valve and there is a secondary check valve located at the end of the fuel fill line just before the HPL. When you fill, the entire fuel system is pressurized up to the LPL. If you get a leak (ice or dirt in the nozzle) the most fuel that should vent is what is in the line between the fill nozzle and the tank. If that check valve also fails you would get the additional fuel from the regulator to HPL added. If both check valves failed and you turned on the key, the tank would pressurize the lines again for a moment and then the HPL would close, venting fuel again. So---until you can get the nozzle repaired---try to leave the fill hose connected a little longer before releasing it to allow it to vent through the station plumbing. If you do remove the nozzle and it is still venting, I would not try to re-attach it for fear of a spark from a static discharge between the vehicle and the fuel hose. Just let go. It should stop venting quite quickly on it own.

[notdeadyet]

Re: Fill Valve Leak

Yes the fill Nozzle is failing after close to a decade of refueling. the problem will get worse. Over the years debris has scored the seating surfaces. SNO-Motion Solutions/ Go Natural CNG can build you one for about 300.00 an OEM will cost around 700.00.

[Hewey]

Re: Fill Valve Leak

Howdy All,

My fill valve used to leak after filling, but since I started to lubricate the fill valve O-ring regularly with a touch of grease, it has not done it since.

I mentioned this tip previously in a similar thread, but have not heard whether the trick works for others too. Please try it and tell what happens.

I'm not sure of the details, but a dry O-ring seems to make the fill valve to leak after filling. By the way, those of you who have leakage after filling, have you drilled a hole to the dust cap? It's kinda frustrating to try to use it when even a little leak pops the cap off from the nozzle.

Best Regards, Hewey

[TOMTGT]

Re: Fill Valve Leak

Sometimes when it is cold your fill recpticle will leak. Dont be afraid. If you are at the fill station push the nozzle back on, ( the hose should not make a spark it has a high resistance ) then turn the threeway valve to the center position so you can stop the flow. Stopping the flow will stop the additional freazing (JT ) If the gas has moisture in it will make the nozzle leak. You have to warm it up, the first step is stopping flow of the gas.

On some vehicle we actually put a 1/4 turn valve just behind the recepticle. If you do this on a Cav. you will have to bag it and vent it to the outside but it is not that hard to do. This will give you a positive gas stop. We have replace so many recpticles on Cavs I cant count. If you rebuild the secondary check valve you should use a Kel-F oring in the Hoke check valve, We have them in stock. $15.00. A rubber o-ring will fail again. The Kel-F is almost permanant. There is no one size fits all fix. I hope this will help you
Tom Sewell
Tulsa Gas Technologies.
918-665-2641

[Tax Counsel]

Re: Fill Valve Leak

Hey Fellow CNG'ers!

Have you ever had your fill valve leak?

I have twice now and it's got me nervous! I bought my 2001 Crown Vic used and it didn't have a dust cap.. needless to say I've now got one on order!

What happens is when I'm done with a fast fill and remove the hose, the fill valve on my car is hissing and leaking CNG! Nervously, I re-attach and remove the pump's hose a few times. Fortunately, this seems to stop the leak..

Has anyone else had this happen to them? It's got me rattled and afraid of being stuck Thanks!

I had the fill valve on my '97 Crown Vic replaced at Alt Fuel Technologies in Huntington Beach.

I'm not sure if they're still around, but here's the phone number I have on file:

714.842.3017

Edit: I just checked the number, it rolls to their voicemail so I assume they're still in business.

Edit: I also recall that they re-plumbed the fill pipe and used a standardized fill nozzle for $400 in lieu of the OEM fueling stem (which was $1,200 at the time).

TC

[Curtis]

Re: Fill Valve Leak

I think the key here is that you have no dust cap. Debris can collect in the nozzle when the cap is not in place. The smallest amount of dirt can cause the check ball to not seat correctly.

I would wash the nozzle as best you can and use high pressure air to clear and dry the inside of the nozzle prior to putting the cap back on to prevent dirt from getting into the cap and contaminating it.

Be cautious that you don't blow out the o-ring inside the nozzle and inspect it for wear. Replace it as needed. The only problem I see with lubricating the area (as previously suggested) is that grease and oil collect dirt and dust and could add to the problem over time.

[Hewey]

Re: Fill Valve Leak

Curtis: Thanks for your thoughts about this issue. I thought already that no one is taking me seriously.

I have doubts that the debris would really be the worst thing with these after filling leaks. As soon as my receptacle started leaking, the dust cap became practically useless as the leak would have blown it away. If not directly, the following ice-buildup would mess it up. So I have not used it since. I just briefly wipe the receptacle clean with fingers before connecting the filler hose. When you connect the filler hose, some gas will go upstream and blow the rest of the dust from the receptacle to the drain line. If the dust cap would be so critical to use on the car, why doesn't the filling hose nozzles have dust caps too? They are in the open air all the time and if you look into them, they're not so clean many times.

What really made the difference was the O-ring lubrication. I use regular lip balm, just a thin layer, which practically dries on the O-ring surface. It is only really needed in wintertimes, when the freezed O-ring looses it's flexibility.

What comes to the ambient temperature and waiting for the ice to melt, it's natural that in summertimes it helps when you wait after the fill-up with the hose still connected. The high ambient temperature will heat up the system, which was cooled below the freezing point (because of the leaking connection), and got ice formed inside of it. When the ambient temperature goes down, near to the freezing point, you'd have to wait kinda long for the system to heat up and melt the ice. When the ambient temperature goes below freezing point, waiting will only support more ice-buildup. But this whole waiting thing is just a remedy for the root cause, which to my understanding is leak during filling, due to dry/hardened O-ring. Go ahead, wait as long as you like, build extra valves, read out loud magical spells when disconnecting/connecting the hose, what ever...

I'm not encouraging others to neglect dust cap protection, please use it to be on the safe side. Maybe drill a little hole on it, if the receptacle sometimes still leaks a little. I just don't care anymore, because to my experience it is not really connected to any of the problems I've had with the system. I recently changed the particle filter and it was not very dirty. 130 €'s down the drain. I think the fluidic contaminants are more of an issue for the system and thus the coalescing filter cup bleeding would be the important thing to make regularly. And if the coalescing filter seems to work fine, collecting oil and water away, why should it ever have to be renewed? (80 €'s down the drain last summer) It should not be plugged by particles, as the upstream particle filter covers this job. The filters cost pretty much, so I'm not going to change them anymore if they really are not plugged at all. Maybe there can be big differences with the gas purity around the globe, but I don't like paying for contaminated fuel and then for cleaning of it myself.

I'm not trying to be hostile against anyone, I'm just getting bored with NGV's. The whole idea why I tried the whole thing, COST SAVING, has backfired on me. Every freaking part costs like hell and the original service network will rip your guts off if you can't do the job yourself. Poor individuals try to survive with their uncommon cars, fooling everybody (including theirselves) questioning whether it is really worth it or not. Before the number of NGV's really go up, people have to pay the prize of limited to none aftersales business competition. My thumbs are up for new NGV drivers, may your journeys start better than mine.

Best Regards, Hewey

[notdeadyet]

Re: Fill Valve Leak

On this whole fill nozzle thread if you are leaking while filling it is a bad O-Ring!
If leaking after then it is the fill nozzle the overall life span seems to be around 9 to 11 years depending on location.

[medgerton]

Re: Fill Valve Leak

On this whole fill nozzle thread if you are leaking while filling it is a bad O-Ring!
If leaking after then it is the fill nozzle the overall life span seems to be around 9 to 11 years depending on location.

I have a 2001 F150 that fills fine and starts to leak out the fill nozzle immediately after removing the filling hose. I put the plastic cap on and it stays on but CNG is leaking the whole time. The truck starts and runs fine. But leaks from the filler nozzle until the tank is empty.

What is the fix?

[larrycng]

Re: Fill Valve Leak

Sound like you have more than one problem Medgerton.

If you have have fuel coming out the filler nozzle then check valve in the Ford fill valve is leaking, replace the fueling connector.

When the vehicle is parked and turned off (you say it is still leaking) then where is the fuel coming from? Probably from the fuel tank throught the tank valve (and then out through the fueling connector). There is a solenoid valve on the inside of the tank valve that is spring loaded closed when the key is off or when the key is on (after about 2 seconds) and the engine is not running. It sound like the seal on the plunger of the solenoid valve is leaking or there is a piece of dirt on the valve seat allowing fuel to leak back to the fueling connector. Defuel the tank and replace the tank valve.

I would have the above done by a trained professional. If you are trained and know the system, you might able to check both of the valves to determine the cause of leakage -- you might get lucky.

If you wait a while you shouldn't have to defuel the tank it will empty itself from what you say. Alway double check to make sure there is no pressure in the system before you break any connections.

That is might take on it.

Larrycng

[Hewey]

Re: Fill Valve Leak

Medgerton: Would you be kind enough to test my trick? I was having the same problem, almost every time when I filled up the tank and disconnected the filling hose, the filling nozzle kept on leaking.

So if you want to try this, drive the gas tank empty so there is no leak anymore. Let the system heat up to the ambient temperature, overnight would be surely enough. Blow any debris out from the nozzle by pressing the nozzle check-valve with something sharp (I use the car key, which happens to be small enough, but a little screwdriver would be perhaps better). Of course you can use also compressed air or just blow it yourself. Apply a thin coat of lip balm or something similar onto the O-ring. Fill up the tank again.

This trick will work if your O-ring is just old and hardened. If it is worn out, try to find a replacement O-ring before changing the whole filling nozzle. If even a new O-ring will not do the job, go ahead then and change the whole nozzle and/or more components from the system. But why change expensive units, when the chances are that only one little thing in it has malfunction?

Best Regards, Hewey

p.s. it would be nice to hear from the fellows who are helping others here, whether they have had similar problems with their own cars, and how&why they have come up with certain gear renewals. There should be a clear line between sharing good practices and component sales marketing.

p.p.s. I'm not sure even if the lip balm could have aided the check-valve seating surfaces too, since I applied it pretty much the first time. Maybe some of it was carried onto the valve surfaces by the gas during the fill-up. This or that, since I started to apply some lip balm into the O-ring, the filling nozzle has not been leaking ever again.