Fuel Leak

[ecoangel]

I had a fuel leak that appeared to be between the tank and the filler neck joint under the car. Noticed this on the Flavia forum:

Author: carlo venturi (146.133.224.---)
Date: 07-01-02 09:13

Dear friends,
has anyone faced some fuel tank leakage from 815 models? I discovered, from years to date, my 1.8 coupè having it from the threaded collar joining the long iron filler to the threaded brass trunk welded to the fuel tank. I begin to believe that convoluted iron filler culprit of that leakage because I found it not firm in his position (it has no screw\bolt fixing it to the body). I made many attempts to solve the question (changing sealer, removing tank, etc). Is it only a question of torquing that castellated collar to hold in position that long filler? And how can the trunk welding resist against the torque? Tell me also, if anyone checked his fuel tank at a professional shop. Regards, Carlo.

P.S. Flavia 815. spare parts manual, does not state any improvement during fuel filler construction.

But no replies.

Anyone had similar experience?

[Huib]

There should be a rubber ring between the filler pipe and the thread on the tank. The rubber itself has a square cross section. I simply install an O ring. I don't trust rubber with petrol so I use a Viton O ring

[m!]

I had a similar experience of losing fuel but it was solved by tightening the collar somewhere along the pipe that leads to the tank.

I don't think the problem reoccured

m!

[P. de R. Leclercq]

Yes, Huib's procedure is identical to that which we used at Evolution.

We could never source the square O rings so we used round-section Viton ones. I also used to add a bit of black Silicone sealant, just to be sure.

Recently on a Fanalone I had an emergency. The filler pipe had worked loose owing to an over-stiff filler cap. The looseness had caused the ancient O ring to start to disintigrate. With no alternative and no time, I "rebuilt" the O ring with the magic "Aero" silicone, tightened it all up and fitted a better filler cap.

And now it's fine!

Paul

[Randy Adams]

Somebody once told me that the silicone sealer expands when it makes contact with gasoline, sometimes so much as to clog passages. I never tested this myself.

[P. de R. Leclercq]

Yes,

Well often I have taken engines apart that have been bunged up simply because people do not understand the simple fact that "more is often too much".

Sealants should always be used sparingly.

Paul

[Thibaut]

Hello all Lancia enthusiast, and long 2007 year !

by the way, i post a complementary question about fuel leek, concerning a fulvia coupé (mine).

i found recently that turning (sharp) left side would lead to a fuel smell in the cockpit
no smell when turning right, no smell at low speed : i thought about a level of gaz leeking from the top of a gaz capacity in the engine compartment : either the fuel filter bowl or the carbs themselves.

but the point is i can't find where is this leak, the top of the carbs has been tightned properly, no trace of fresk leakage there...

by the way, i should ask a beguinner question here : how can i check the fuel level in the carbs properly ?

Thanks a lot to all of you,
Thibaut

[Huib]

S1 coupes and Zagato's except for the latest ones occasionally suffer from petrol fumes on winding roads. Even more so in hot weather.
It is related to the ventilation of the tank. The ventilation hose goes toward the C pillar and then through the bottom of the boot under the filler cap box.
The later S1 Fulvia's and all S2/3 Fulvia's have a black box bolted to the right rear wheel arch. They don't have the problem.

Taking the filler cap off and putting it back keeps the fumes away for some time.

I have never solved it and in fact it is some years ago that my coupe suffered from it. The last few years no fumes. I did not conciously alter anything. Since winding roads include bot left hand turns and right hand turns, I don't know if either contributes and the other does not.

Good of you tho bring it up. Next time it hapens I will check if it is on left turns only.

The black box on the later Fulvia's is an empty box. Apparently the ventilation system for the tank needs more dumb space to hold expanding gasses.

[thibaut]

Well, i should ride the car more , but i am pretty sur this phenomenon occurs when i turn left, letting the centrifugal forces push the gas the right side, where are all the gaz related items (filling tap, neck at the rear, filter/decanter, carbs at front)
i do think it could occur from the back of the car, even if the "logic" would lead to think that one smell more a fume from the front of the car.

as my car has mounted the plastic black box described by Huib, i could think of possible leakage (fumes or gaz leakage) from the filler neck (wich brass nut was found to be lousy once last year), and/or the tap (reassembled with a bad gasket made of air chamber.
turning left would get gaz fumes to move out from there, and enter slightly in the car. As i had to remove the back seats, it could explain...

Let's inquire more and wait and see... !


Thibaut

[Tim Heath]

On this subject I noticed recently on filling my series 2 zagato up full of fuel a strong smell of petrol immediately afterwards. This has happend twice recently and I suspected the new fuel tank I fitted.

However, I can see no leaks - they would be very obvious as petrol leaches across the the matt black painted tank and I would see this very easily. More curiously the smell disappears after about 10 minutes driving and certainly never comes back. Does anyone suspect the breather box having a leak??

By the way, I can confirm that when I took the filler pipe off the old tank the rubber seal crumbled into a thousand pieces. Needless to say the new tank was supplied with a flat rubber gasket from our good friends Cavallito.

Tim