gas tank gurggle

[jenz]

I am having a gas problem. Not me personally but my van. What happens is this: when it is very hot or when I am driving at high altitudes, above 7000ft there is a very strong gasoline odor and a boiling noise. As if liquid is boiling on a stove. You can actually feel the vibration if you touch door to the gas filler area. If I open the gas cap, pressure will come from the tank for over 10 minutes, thats with it just cracked. If I open it all the way, gas will actually spew out. It takes an extremely long time for the pressure to release completely.

Here are a couple of fixes that we have tried:
1. changed the gas cap, 3 different times, no change.
2. changed the fuel filter, assumed it probably wouldn't do anything but couldn't hurt. No change
3. used a high octane gasoline the last few times I filled up, no change
4. just got it back from the shop and they said that there is a screen on a purge valve that was plugged and they cleaned it. I thought that would be it. I just returned from driving about 40 miles, its 100 degrees out and i live at about 4700 and when I got home i could smell fumes, i cracked the gas cap and tons of pressure and gasoline came out. No change!

The vehicle is a 2000 Rialta which is essentially a eurovan with a winnebago camper.

Any ideas? Anyone out there here of this issue? Any solutions? I am to a point where I am a bit afraid to drive it as I really don't want it to catch on fire and blow up. Please help as I would love to get out of the heat and up into the mtns!

 

[mloganusda]

Go to the yahoo Rialta-Tech site and join. Search the files and message info for this problem. It has been discussed several times lately.

 

[newuserguy]

Please post solution here if you figure it out. I had the same thing happen to me while driving through the Nevada desert last week. Very concerning.

 

[newuserguy]

The answer is basically a combination of the gas tank over heating because it's located directly aft of the engine (most vehicles have the gas tank further away), over filling the tank (which I did the very first time I filled it), and altitude.


From Rialta-Tech:


"This has happened to me as well, in fact just about every time I drive in
temperatures over 90 degrees it happens. From what I have been able to figure
out, it's a common problem for the Eurovan, as the gas tank is right behind the
engine and all the hot air from the engines flows past and around the tank.
When you reach a certain temperature, the fuel starts to boil and the pressure
inside the tank soars, and if there are any holes/gaps in your fuel lines
(including the one to the generator, which is where I have issues) they're going
to start leaking.

Most vehicles the fuel tank is a long way from the engine air flow, the Eurovan
was almost unique in putting it so close and right in the air flow.



REPLY:



WHOAAAAAAA Dobbin!!!

Don't rush into the VW dealer for an emission job. I was quoted $1,200 to
replace the EVAP canister last year. The part was $296 making the labor roughly
$900. A local independent shop doing only German vehicles quoted me the same
$300 for the part but only $400 for labor. I did the job myself in an hour for
just the $300 for the canister. Having done the first one (on my back), I could
do one in 15 to 20 minutes max. It's six screws, 2 bolts and 3 lines.

The place to start is the purge valve. It's a small round barrel looking valve
near the firewall about an inch and a half long and maybe a little larger than a
quarter in diameter with a hose on each end. When the system is working properly
as fuel evaporates in the tank, its accumulated in the EVAP canister, which is
just a big plastic box filled with charcoal pellets. It's stored here until the
engine is started. When the engine is started the purge valve opens and the
engine vacuum draws those fumes from the canister into the intake manifold where
they are burned rather than released into the atmosphere like the good ole days
when tanks were just vented to the outdoors. To test the purge valve, first
locate it. Then start the engine and let it idle. You can touch the valve and if
it's working properly you should feel a slight rattle or vibration as the little
ball moves back and forth. If the ball (valve) is stuck, you might be able to
clean it with a good solvent like mineral spirits, or carb cleaner until you can
get the ball to rattle. If cleaning won't get the job done, a new one is about
$65 from VW if memory serves me correctly.

Here's my caveat. When the EVAP canister fails it's a result of topping off the
tank. The pellets were designed to handle vapor, when you top off the tank
liquid fuel flows into the canister, in effect enlarging your fuel tank capacity
by about a gallon. Unfortunately this turns the pellets into a charcoal mud,
that will eventually outgas the fuel vapors "maybe" allowing a slight venting,
which is likely to sound like the gas boiling in the tank. The next step will
likely end up being only able to get less than a tenth of a gallon into the tank
at a time before the shut-off stops it. It will take you 45 minutes to fill the
tank when that happens. You'll see 18-wheelers filling and going while you're
still there with the hose stuck in your spout. Check the purge valve first (mine
was fine), and if that's not it....look to the canister....sadly there's no test
for it.
Denny
02-HD"



Basically, if it only happened once, my understanding is the pellets in the EVAP canister should be able to dry out and function again. If you flooded it too many times or got unlucky, you should test that part and replace it if it failed.

 

[Bernie-ClassB]

To Rialti - Tech


I have the same problem with my 2000 Eurovan camper. Maybe the Eurovan is running hotter than designed because of the extra weight from the camper. Would it help to wrap insulation around the exhaust pipe adjacent to the gas tank?


Bernie

 

[mloganusda]

Wrapping the exhaust pipe close to the gas tank would not be a bad idea. You can buy the exhaust wrap at most auto parts stores as it is used on turbo and header exhaust pipes.

 

[Merri Lu Park]

Hi jenz


Can you update me. We are the proud owners of "Dewberry", our 2001 FD. We have a very similar problem. We have not driven for more than a week but still hear the bubbling sound sometimes. Did you fix the problem? What worked for you? How many miles have you drive since trhe fix?

 

[Merri Lu Park]

Please excuse my typos. Next time I will read it before I send.