Sticky Blue Goop

[sailon]

Last weekend here in Florida I noticed a sticky blue substance under the wing just outboard the wheel well, and on the pavement under the wing.  My wing tanks have been replaced with bladders.  At first I thought it was a fuel leak, however, the substance was the consistency of tar, blue in color, and very difficult to remove.  We recently have had a cold snap (by Florida standards that is).  Has anyone seen this before?

Thanks

[Prior owner]

Hmm.. I have seen tar like deposits that were old fuel leaks. Eox cleaner dissolved them with a gentle scrubbing

[orionflt]

Make sure your bladders don’t have a leak. The area you are talking about probably has a coupling between bladder segments. 

As for cleaning old fuel stains, I use fresh fuel to clean it off. Then just wipe it down with a mild cleaner. 

Brian

[sailon]

I have never seen a fuel leak with the consistency of tar or chewing gum.  Have you?

 

 

[orionflt]

I have, but all old fuel that had been there for a while. A good picture would help otherwise we are all just guessing 

Brian

[Prior owner]

Does it look like this? I Don’t have a pic of the really thick stuff that I found on my own plane, but here is a little bit of goo from a leaky drain valve and sending unit...

Edited February 5, 2019 by PilotCoyote

[carusoam]

With a Mooney....

You Only have so many choices...

Blue, is common, since it is THE fuel additive to indicate it is 100LL... The sticky brown stuff is probably the TEL that is being left behind...

Fuel tries hard to leak out...

When it does, it likes to seep far and wide from its source...

While researching a plan of attack....

Consider studying the various connections between the various parts of the individual bladders... 

Then go find the one that is leaking...

If your mechanic is familiar with the bladder system used in Mooneys this could be quite easy...

Use caution with powered screw drivers while searching for fuel leaks... static electricity during the dry winter months can also be a similar challenges...

Got a pic of where the leak is showing up?

Look up threads regarding bladder installation for examples...

Some people believe with bladders... they won’t ever have a fuel leak... Realistically, they have a bunch of connections, and hoses, and other things still that leak....

Check the logs to see how old the system is, and where it was installed... additional info that may be helpful to finding answers...

PP thoughts that come to mind...

Best regards,

-a-

[MinneMooney]

I would recommend using mineral spirits versus 100LL. It is much safer to work with from a flammability and skin exposure standpoint. It should do an equally good job of dissolving tar-like deposits, but it will still take some elbow grease. 

[Boilermonkey]

Some anti corrosion fluids are that color too.

Sent from my SM-G960U using Tapatalk

[sailon]

1 hour ago, Boilermonkey said:

Some anti corrosion fluids are that color too.

Sent from my SM-G960U using Tapatalk
 

Now that is what I was thinking of.  There is a drip on the hangar floor, but it did not spread.  It glopped up like tar, and 100 LL does not dissolve it readily.  Fuel that falls to the floor disappears and leaves a stain on the floor but not a glop.  I can send photos when I get home tonight.  I was thinking of either anti corrosion fluids or perhaps some old tank sealant that dissolved slightly when I filled the tank last.  This is a weird one.

 

[carusoam]

Don’t expect tank sealant to dissolve on a good day... without the really specific sealant dissolver...

was anyone cleaning the old tank sealant out lately?

 

 CorrosionX feels kind of waxy, looks kind of brown in thick layers...

Probably doesn’t flow much after a few moths after application...

 

Evaporated 100LL feels kind of sticky, extra dark like a good beer... in thin layers, when wiped with a towel... it is blue...

 

none clean up very easy without a good solvent...

 

Hope for a good hose clamp solution...  

 

PP thoughts only...

Best regards,

-a-

[jaylw314]

Maybe this is an obvious question, but is it actually from your hangar roof?  I don't always get my plane in the exact same spot every time...

[skykrawler]

Some fuel bladders are 'self sealing' if they develop a hole like from a rivet head.   Some old military bladders are designed to take a projectile and re-seal.  I have seen older Cessna 182 bladders emit a goop in this process...typically getting near the end of life.  C182 bladders are 10-15 year things.  Seems like there would be some goop around the source hole on bottom of wing.

[Prior owner]

Having stripped a tank, I cannot believe that it would be possible for tank sealant to dissolve unless it was on fire