Fuel Filter - teflon tape on conx?

rjbathgate · 20 July 2011, 03:07

Hey,

I have myself a fuel filter, something like the attached picture.

It has 4 x connections (one in, one out, two blocked).

There is no mention of it anywhere in the small piece of paper that came with it, but should I put (fuel-happy) teflon tape on the threads of the 4 connections before screwing them in, like a plumber would on water or gas connections in your house?

Reason I ask is that I have put it all together and screwed it in, and THEN thought about tape... so if it is 'recommended' or 'required' then I have to drain it and take it all apart... something happy to avoid if there is absolutely no need whatsoever... but also want to make sure I don't turn my boat into a bomb.

Have had it running for 5 mins and no leaks seen...

What would you do?!

captnjack · 20 July 2011, 05:01

Yes to tape, but leave the first few threads of the male end of the fitting tapeless so little flecks don't get into your fuel. Particularly important on the outlet fittings, not a big deal on the inlet of course since the filter itself will catch them and prevent the fuel pump or injectors from clogging with teflon bits.

I'd be surprised if the fittings sealed completely without tape. And leaky fuel fitting are not good.

rjbathgate · 20 July 2011, 08:30

Quote:

Originally Posted by captnjack

Yes to tape, but leave the first few threads of the male end of the fitting tapeless so little flecks don't get into your fuel. Particularly important on the outlet fittings, not a big deal on the inlet of course since the filter itself will catch them and prevent the fuel pump or injectors from clogging with teflon bits.

I'd be surprised if the fittings sealed completely without tape. And leaky fuel fitting are not good.

Damn! Means I do need to flush and take off.... but it is of course best to be safe then very very sorry...

Is it called "Teflon Tape (fuel version)" that I'm after? or have I made that name up?

Erin · 20 July 2011, 08:41

I seem to remember using thread lock on mine. Either a loctite product or hematite. However, I'm sure Teflon/PTFE would be fine and certainly better than nothing at all.

martini · 20 July 2011, 08:44

We normally call it PTFE tape, it's not much good with fuel, better to use a joint sealing compound like hermetite red.

Personally, if it's already assembled and not leaking I'd leave it for now and just keep an eye on it. The thread on your fittings is probably NPT or BSP, both tapered threads so may well seal themselves sufficiently.

jyasaki · 20 July 2011, 14:37

Auto supply places should have gas-compatible thread sealant (aka plumbers putty.) Look for a non-hardening type.

Teflon tape is not advised (but it is usable) due to the problem Jack mentioned.

jky

captnjack · 20 July 2011, 15:21

Quote:

Originally Posted by martini

We normally call it PTFE tape, it's not much good with fuel, better to use a joint sealing compound like hermetite red.

There's a fuel compatible type, I've used it and its still on my fittings. I have no idea were I got it, probably an autoparts store.

Hightower · 20 July 2011, 18:37

It's a bad practice to use plumbers tape (PTFE) on anything carrying liquids such as Hydraulics and Fuel. If the tape gets into the system then it can cause all sorts of problems. Best to back the hose tails out a little and use some liquid sealer such as Loctite 542 or similar. Make sure the fuel system isn't under any pressure and you should be lucky enough to unscrew the fittings without fuel leakage so that you can apply the sealer.

rjbathgate · 20 July 2011, 20:28

Quote:

Originally Posted by Hightower

Best to back the hose tails out a little and use some liquid sealer such as Loctite 542 or similar. Make sure the fuel system isn't under any pressure and you should be lucky enough to unscrew the fittings without fuel leakage so that you can apply the sealer.

I like that suggestion! makes it (hopefully) easier.

Thanks everyone for all ur help