Under Dash Fuel Shutoff

[spinelll]

Do I use Permatex #2 on the threads between the shutoff and the fuel tank?


Len

[Dick M]

I use NAPA product #56521 "High Performance Thread Sealant" made by Permatex. I do not know if this is the same as Permatex #2, however, the #56521 is made for threads exposed to gasoline. Works very well...

[Big hammer]

I use Permatex 2 for late 31 indented firewall gas valve , no leaks and you can remove later without issues

[JayJay]

I use Permatex 59214 "High Temperature" thread sealant. No reason for the "high temperature", it's what was available at my local O'Reilly when I went looking. I let it set up for 24 hours before refilling the fuel tank. I've used it several times with good success.

It's not the same stuff as Permatex #2. For one, it's white not black, and secondly it's a lot thinner. I don't think Permatex #2 has Teflon in it, which is desirable to prevent galling when fitting dissimilar metals (the tank is steel, the valve is brass).

A word to the wise - I have not yet found a thread sealant that lists compatibility with gasoline. Lots with oil, several with diesel (including the #59214), some for use on "fuel systems" but none that specifically state OK with gasoline, especially the alcohol-infused crap we have to buy in the People's Republic of California. But the #59214 seems to work for me in the tapered fitting on the bottom of the fuel tank.

JayJay

[katy]

Originally Posted by spinelll

Do I use Permatex #2 on the threads between the shutoff and the fuel tank?Len

No need to use it on the flare nuts threads.

[Bill G]

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5 years ago I replaced the valve under the dash and no sealant at all. Not a drop in all that time.

[Ray in La Mesa]

Yellow Teflon tape has worked for me for many years.

[Hughes Automotive]

I would only use sealant if you are repairing a leak.

[rich40701]

Years ago I was working on an inboard and OMC recommended using Permatex high temperature thread sealant and 17 years later still no leaks. I have also had good luck with Loctite PST 592 pipe sealant with PTFE; both need to cure before use.

[dave in australia]

I use permatex #3 non hardening sealant. I don't recommend teflon tape as small strands can tear away and block different parts of your fuel system further down stream.

[Tim Ayers]

I used ARP sealant since I had some left over from the engine build. It's only been 6 months, but no leaks.

[midgetracer]

I use a product called Gasoila. It is white paste and I have never had a leak with it. My local NAPA store handles it because the oil industry folks here requested the handle it.

[31a]

No knowledge of yellow Teflon tape??

[1crosscut]

Are the folks here that are using a sealant doing so because they had a leak or is this something that was done as a precautionary measure?

I've not had an issue as of yet assembling them bare.

[Ray in La Mesa]

Yellow tape is used by the propane/ LPG industry.

[dave in australia]

Originally Posted by 1crosscut

Are the folks here that are using a sealant doing so because they had a leak or is this something that was done as a precautionary measure?

I've not had an issue as of yet assembling them bare.

I use sealant so I don't have to over tighten the fittings to get them to seal. I've had a couple weep, and with 90+ year old metal and fatigue, figured sealant is the safer option against cracks/breakages.

[katy]

Anyone on here use Red Rubber Grease for a sealant? It's impervious to gasoline.

[JayJay]

Originally Posted by 1crosscut

Are the folks here that are using a sealant doing so because they had a leak or is this something that was done as a precautionary measure?

I've not had an issue as of yet assembling them bare.

In my case, both. I've found gas tanks that have apparently had the female tank fitting "chased" with a tap such that the valve bottoms out on the threads before it is tight. In that case the sealant works to allow the threads to seal without as tight a fit as I'd normally like without sealant. Other tanks I use the sealant as a combination lubricant/sealant to make sure I don't gall the brass threads against the steel threads.

Which serves as a reminder to avoid "chasing" threads where you cut fresh steel. If you want to clean out rust, fine, but don't go overboard. Applies to straight threads as well but especially tapered pipe threads.

JayJay

[Tacoma Bob]

I was told it's used for gas pipelines.

[katy]

Did Ford use anything on said threads at the factory?