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Drip….drip…

JwWright57

Well Known Member
I was going through my 12Is after the first flight and found a drip on the lower fuel tank line (feed to fuel pumps). It’s really strange. At first i thought it was oil blown back from the engine (oil was a little overfilled) . It has the consistency of oil and no gas smell. So i cleaned everything off and did some pattern work and then let it sit and this was the pic next time. It’s obviously gas, but it doesn’t smell like gas! It’s almost like jellied gas. It has the right color, the car gas i’m using is yellow and this is intensely yellow.

I cleaned it all up again and ran both fuel pumps and stared at it for a few minutes and didn’t see any leakage whatsoever. Double weird!

I guess the next step is to drain the tank and take off that line and see what the heck is going on.

Anybody seen anything like this?

BTW, engine seems like it’s running fine. I did have a slightly low fuel pressure while doing the climb to 10k test ( at around 9400 feet) don’t know if that means anything.
 

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Drip..... Drip

It is gas that is a very slow seeping leak. It turns to a dark oily drip. I hand to reseal twice. You just have to figure if a fitting or a seam
 
This is what happens when accelerated evaporation happens.

Some of the petroleum components in the fuel are more volatile than others.
Add some airflow to carry away the vapors and you end up with what you see.
 
I had a weeping carb bowl gasket and it looked like oil in the drip tray when I did my preflight inspection. AVGAS is less ambiguous leaving a blue stain.
 
update.......

It looks like my little weep is coming out of the connectors at the bottom of the tank.

I'm on my second 45degree fitting, the first one seemed like it was a little stripped and was leaking when I filled the tank with water for a test.

So I replaced it and made that sucker as tight as I could get it and still have the right orientation. Alas, it seems like there is still a tiny, tiny leak there. Not sure what to do about that and would LOVE some suggestions.
 
If it is coming from the threads, a fuel-compatible thread sealant like Loctite 567 should stop it. If it is coming from somewhere else around the fitting, good luck!
 
To confirm the location of the leak, tie lengths of string to each possible location. Let each string hang down. The gasoline will follow the string down. The wet string will lead to the leak. If Loctite 567 isn't fixing the problem, consider using fuel tank sealant.
 
To confirm the location of the leak, tie lengths of string to each possible location. Let each string hang down. The gasoline will follow the string down. The wet string will lead to the leak. If Loctite 567 isn't fixing the problem, consider using fuel tank sealant.

yes I was thinking the same thing. I'm going to loosen the 45 as much as I can (it'll only go a qtr turn before hitting the other fitting) and throughly clean, put some pro seal on the threads and tighten back up and hope for the best.

I'd really like to know why the aluminum block fitting is not long enough to take the 45 degree fitting off without having to remove the other one first. It's a major flaw in my opinion. I'm guessing Vans gets these off the shelf somewhere. Also, why not just two straight fittings? It's easy to put a bend in the fuel line. Then you don't have to worry about cocking the 45 a certain direction and can get it as tight as needed.
 
Yes, Jeff, the 45 deg fitting is a real issue and doesn’t allow one to follow the latest condition inspection check list regarding the finger strainer. I had initiated this post asking what others were doing, but the defending silence pretty much answered my question. And Van’s Support couldn’t tell me how they address this on their trainers either.

https://vansairforce.net/community/showthread.php?t=197084&highlight=Finger+strainer
Yes totally agree. If I have to proseal the fitting to stop it from leaking there is no way I'm going to ever take that off again.
 
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