Can I use RTV as Pipe Thread Sealant?

[rbattelle]

I've got a 3/8 NPT fitting that will NOT stop leaking. I've tried Teflon tape 3 times, and SWAK (Swagelok anaerobic pipe thread sealant) 2 times and it still has a minor leak. It's only carrying about 14 psi of diesel fuel for my fuel system.



I bought this stuff called "Rectorseal" but it looks awful runny and it's non-hardening. So I was thinking of just going right to RTV on the threads. Is this acceptable?



Any advice is greatly appreciated. This fitting has been driving me nuts for 2 weeks now.



-Ryan

 

[bmoeller]

If the leak is after the fuel filter, I would NOT use it for sure.



I have heard that using the tape AND thread dope together works well. Haven't tried the idea yet.

 

[supeerman4422]

tefflon tape and pipe dope is the way to go! trust me im a plumber!... well an aprentice anyway lol!



-Tom

 

[rbattelle]

Fortunately, the leak is at the INPUT to the filter, so there's no worry about contaminants getting in. I had considered using BOTH tape and sealer, but I didn't think that was accepted practice and didn't want to end up with a total mess.



I ordered a tube of Loctite thread sealant number 565. In the meantime I put a double-layer of teflon tape on the fitting. It's a very very slow leak; if I weren't so obsessive about leaks I wouldn't even bother with all this effort.



-Ryan

 

[nickleinonen]

rtv can work, so can permatex #2 and hylomar works too... i use plumbers teflon dope most of the time. it works very well. [heck i have used the dope to seal up leaking jic fittings that had the sealing face slightly damaged - suction side of electric oil pump though]

 

[rbattelle]

rtv can work, so can permatex #2 and hylomar works too... i use plumbers teflon dope most of the time. it works very well. [heck i have used the dope to seal up leaking jic fittings that had the sealing face slightly damaged - suction side of electric oil pump though]

I'm not entirely sure what you guys mean when you say "pipe dope". Is there a difference between it and "thread sealant"?



-Ryan

 

[Tony T.]

Ryan



My understanding was teflon tape is not compatiable with diesel fuel unless it's a certain kind made to be compatiable, of course that may be what your using. When I did the vent kit on my fuel tank that Dave supplies, he listed a compatiable sealant to use which is Permatex (thread sealant with teflon 14H Item #80632). I purchased the 4oz bottle at the local auto parts store. Something you might try,hope you get it fixed.



Tony

 

[nickleinonen]

I'm not entirely sure what you guys mean when you say "pipe dope". Is there a difference between it and "thread sealant"?



-Ryan

they might be the same... the brand i use is masters pro-dope... it might be a local product as their HQ is 30 min north of me... it is the teflon gooey paste that can be found at homedepot or other building supply company in their plumbing section [usually by the black iron pipe and teflon tapes] it comes in a tin can [±3. 5" diam x ±3" tall with brush applicator on cap]



i am not actually 100% sure it is diesel rated, but we use it at work on diesel fuel lines and don't have any issues [then again, we use regular plain teflon tape on those lines too with no issues... ] and we use it on the water lines and lube oil lines that have npt fittings... when i was working in building maintenence dept. at work, i used this same dope on the HP wash system pipe fittings too. . they run at ±2,000psi and it sealed better there than permatex #2 did... when i was working on the boilers for the maintenence, we used it on the natural gas lines too [also used the lead based pipe sealent there too]

 

[Yo Hoot]

I've got a 3/8 NPT fitting that will NOT stop leaking. I've tried Teflon tape 3 times, and SWAK (Swagelok anaerobic pipe thread sealant) 2 times and it still has a minor leak. It's only carrying about 14 psi of diesel fuel for my fuel system.



I bought this stuff called "Rectorseal" but it looks awful runny and it's non-hardening. So I was thinking of just going right to RTV on the threads. Is this acceptable?



Any advice is greatly appreciated. This fitting has been driving me nuts for 2 weeks now.



-Ryan

If it's a real b-buster I would suggest replacing the fitting. Sometimes the fittings aren't made just right and can be much easier to just change out than to play with a leak.



Now when I have a real problem and I have to use the fitting I use this blue stuff called BLOCK. Get it at the plumbing dept at Home Depot or Lowes. Made by Hercules. It's thick and it cures to a solid but flexible bond. Reading off the can..... "Use for water, steam, oil, gases, gasoline and more"



Everytime I have used it on a problem fitting it worked first time. I now use it all the time.



Never heard of Rectumseal :-laf

 

[JBlock]

There actual a yellow tinted teflon tape made for hydrocarbon service if you can find it. It does breakdown over time. Joe

 

[rbattelle]

I am using standard white Dupont Teflon tape on 3 of my fuel line fittings (inlet/outlet from the pump, and now the inlet to the final filter). Have not yet had any problems at all with those, but I will monitor closely.



This "Block" stuff sounds interesting... I will look for it.



-Ryan

 

[JBlock]

Block

"Block" that my last name cool

 

[Yo Hoot]

Looks like this...



#ad




#ad

 

[JCyrbok]

I have never had a problem with Permatex #2. I even use it if I am doing plumbing behind a finished wall, like a shower or faucet stub out. It have never failed me.



Hope this helps,

J-

 

[DAWG-1]

Tape

If you use the white teflon tape it "will" breakdown over time. You need to go to the plumbing section and find the Yellow Gasline PTFE Tape. The round plastic container it is in is yellow also, it will be right next to the white teflon tape at Lowes. When wrapping tape on any type of threaded fitting never wrap any tape on the first TWO threads or you could get the tape plugging up something. Sam

 

[rweis]

I've had fairly good success with Rectorseal #5. However NEVER the first 2 thread chanels, EVER with ANYTHING. I stir the Rectorseal up some so you get the thicker googy stuff not just the thin liquid.



Bob Weis

 

[JHardwick]

Ryan!!



Stop with the band-aids, lol. Check the tapped hole and the fitting

 

[Elite1]

I have used "Rectorseal" for years on all types of threads, it works better than teflon tape... & yes it is "pipe dope. "

 

[rbattelle]

Ryan!!



Stop with the band-aids, lol. Check the tapped hole and the fitting

You're right. I've already ordered a new fitting, but the tapered hole would require buying a new Stanadyne filter ($70), so I'm hoping the new fitting and some of this "Block" stuff will make everything excellent.



-Ryan

 

[rbattelle]

Why did this get moved to the 3rd gen forums? It's not vehicle-specific!



Anyway, I wanted to put in a plug for Block. It is a very impressive sealant. Cures super-fast to a consistency somewhat like clay. I really like it.



-Ryan