[C320-list] Leaky fuel tank?

[Marek Fluder]

Rick,

Thank you for your advice.
Fuel was pooling at the lowest (forward port) corner of the tank before
overflowing the foot-frame that secures the tank in place.
In the past I have sealed my leaky sender unit on the top of the tank
(another common issue).
This time I did not see any evidence of any leaks from the fittings, hoses
and the side walls therefore I concluded it must be the corner or the
bottom where I cannot see without pulling the tank.
I have snapped some pictures.
<http://www.catalina320.com/mediagallery/album.php?aid=297&page=1>
Your idea of pressurizing the tank partially filled is going to be my next
step.
I would like to have a clear evidence before dropping close to $1000CAD for
a new tank...

Thanks again.

Marek
2005 #1028

On Wed, Jun 22, 2016 at 7:56 AM, Rick <rsulewski at bex.net> wrote:

> Mark,
> I replaced my tank a year ago because I had experienced a nasty sender
> leak over the winter from an overfilled tank and did not want to endure
> another fuel clean up mess over in the next several years given the age of
> my hull (20 years) when the tank could be expected to begin leaking.   My
> reasoning was  why wait for a fuel leak that day was predictable?
>
> Based on my research of aluminum tank leaks across several manufacturers
> most diesel aluminum tanks can be expected to develop leaks within plus or
> minus 5 years of the 20th year.....a matter of not if, but when the tank
> can be expected to leak.  My review of the 320 discussion list pointed
> toward many 320 tank leaks occurring at the lowest portion of the tank's
> seam weld or the lowest portion of the wall nearest the tank's welded edge
> near the forward & portside corner area.
>
> Did you see any evidence of fuel residue in the suspected area of the
> typical 320 tank leak? Have you considered pressurizing the tank with a
> small portion of fuel in the tank? Given the 320 discussion list tank leak
> details I observed, owners seem to report evidence of tanks weeping well
> before the leaks growing worse over time.
>
> When I received my new tank, the tank's fuel filler hose was securely
> sealed with a flexible cup like cover that was pushed onto the filler inlet
> that could also be clamped to that fitting. Also, all of valves were
> closed. When I opened a valve I could clearly hear the air pressure
> equalizing within the tank, suggesting that the tank was still under
> pressure when it left the factory, perhaps due to the temperature
> differences from when it was packed or the elevation differences from when
> & where I am located. This suggested to me that the variables involved in
> pressurizing the tank where tightly controlled by the tank's sealed valves
> and the filler pipe seal and that the tank was still under several PSI for
> a sustained time.  That is why I suggest attempting to replicate the tank
> weeping with a small amount of fuel in the tank for a period of time while
> the tank is left under pressure vs. simply looking for an air leak bubble
> with soapy water.
> Rick
> 1995 320 hull #277
>
>
>
> -----Original Message-----
> From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On
> Behalf Of Marek Fluder
> Sent: Tuesday, June 21, 2016 9:30 PM
> To: C320-List at Catalina320.com
> Subject: [C320-list] Leaky fuel tank?
>
> I have pulled my diesel tank today for inspection based on research on
> this list archive and my observations of diesel showing up in bilge area
> and around the tank. All fittings and sender unit on top were dry. Now I am
> puzzled as I pressure tested the tank spraying soapy water and nothing. The
> tank looks solid. Question to listers that replaced the tank - was the leak
> on the tank obvious?
> I am stumped.
> Marek
> 2005 #1028
>
>