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Fuel Thread Sealants?

I just replaced my failed red fuel cube and used Loctite 565 per Van's support recommendation. They specifically said do not use RTV, Teflon tape or fuel lube. I understand the RTV and Teflon tape. In a lengthy discussion with my A&P he stated he only uses EZ Turn. In searching other posts some are redoing their NPT fittings with Loctite 567 after using EZ Turn. My question is what is the problem with EZ Turn on fuel fittings since many mechanics use it.
 
leaks

All I can say is I do NOT use Fuel lube EZ turn for sealant anymore because I have had it leak in some very hard to work areas in the past.
Not going there again. I have been using Aviation grade Permatex or other stuff I have.
Art
 
There are many different fuel and temp proof thread sealants, and personal anecdotes notwithstanding (this IS the internet, after all), it's unlikely that any one is much, if any, better than another. Over the last couple of decades, I've used many different thread sealants in a variety of automotive applications and strongly doubt that there's a whit of difference between them. Looking at the cabinet in my garage where I keep the stuff...I see that I have more LocTite 567 than anything.
 
I just replaced my failed red fuel cube and used Loctite 565 per Van's support recommendation. They specifically said do not use RTV, Teflon tape or fuel lube. I understand the RTV and Teflon tape. In a lengthy discussion with my A&P he stated he only uses EZ Turn. In searching other posts some are redoing their NPT fittings with Loctite 567 after using EZ Turn. My question is what is the problem with EZ Turn on fuel fittings since many mechanics use it.

I don’t know any mechanics that use fuel LUBE as a SEALANT. Fuel lube or EZ turn is a lubricant, great for fuel shut off valves, but it is not a sealant. When you assemble tapered pipe fittings, there’s a spiral path for fuel to leak at the root of the threads. Using fuel lube is like using vasoline or grease to seal a fuel leak. If the fuel is low pressure, it may hold up for a while intil the gooey ness of the fuel lube starts to move, then it WILL leak. You should always use a sealant that’s made to seal, not a lubricant.
 
So, what’s the difference or advantage of 567 vs. 565? Don’t have both to be able to easily compare. I used 565 since it was recommended by Van’s in Section 5.

Edit: Answered my own question. In case any others were interested - higher temperature and pressure.
 

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Vans now recommends 567 in the latest version of the MM. It's just a higher temp version of 565. (page 1-11)
 
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IMHO, Loctite 567 works great for fuel, hydraulic, and air lines -- it has no issues with ethanol-laced fuel either. EZ Turn/Fuel Lube is great for sticking washers and nuts on your fingertips for easier insertion in tight spaces (I'm talking "airplanes" here). ;)
 
I no longer use “EZ Turn” for anything, switched over to Krytox. Expensive, but works wonderfully on my gascolater bowl and fuel caps.
EZ Turn, for me, wasn’t so “easy” and finally gave it up.
 
I no longer use “EZ Turn” for anything, switched over to Krytox. Expensive, but works wonderfully on my gascolater bowl and fuel caps.
EZ Turn, for me, wasn’t so “easy” and finally gave it up.

For O-rings, I use a product called O-ring grease, I think it’s a Dow Corning product. I used EZ turn on the faces of a tight fuel valve, and it works awesome for that! Many years later, it still moves nice! Amazing when you use a product for its intended purpose!
 
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