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Discussion Starter #1
I've used silicone to stop a diesel leak - it's fine for a month or so before the silicone goes all funny and the diesel starts leaking again.

Is there a diesel resistant equivalent to silicone sealant/tape.

Cheers
 
J

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Where's the leak?

To elaborate on Kenty - if it's a broken hose, replace it. if it's the fuel tank, replace it (or patch it over with a little plastic weld).

It's easier to use heat on diesels cos it doesn't really burn that easy unless you warm it up, and it's not that volatile..

There's a video somewhere of a bloke with a big stick on fire and he dips it in a barrel of diesel to put it out.

---- Just realised I went on a right tangent there :thumb:
 

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Discussion Starter #5
The leak is at the fuel rail pressure sensor- it simply screws into the fuel rail - it keeps on working loose and silicone tape wrapped around the threads is only a temporary solution.

Peugeot say that the pressure sensor cannot be replaced - well yes it can - but it leaks if you don't keep on tightening it up or applying silicone tape.

There must be some kind of diesel resistant thread lock?
 
J

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PTFE - Polytetrafluoroethylene - but in it's tape form. Plumbers use it to create a tight seal within threads.
 
J

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LOL no way omg lmao you're funny rofl. btw wuu2? bbiab.

Did you understand that? :D
 

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Does the sensor originally have a tapered seat? The pressure in that rail is pretty emmense, maybe 15000Psi at full tilt! My guess would be a tapered seat or 'cone' as it is sometimes known, as o-ring seals don't usually get used for anything that high. My guess is that the reason you need to keep tightening the sensor, is that the seat is damaged, and the pressure cycling in the rail, and vibration , are causing it to work loose. If the seal is a tapered seat, the only permanent fix would be to re-cut the seat on the rail and cone on the sensor.

As suggested, PTFE might hold it, but I wouldn't like to guess how long for...
Don't mean to warn you of the obvious, but the pressure in that rail could cause you a really bad day if that sensor came off.

If you have to keep tightening it, it will wear the threads over time ,and at the risk of sounding extreme, could weaken them to such an extent that the threads won't be able to hold back the force created by all that pressure, and the sensor will blow out.

I know this is a bit dramatic, but I am a hydraulics engineer, and design cylinders for a living, including calculating thread strength requirements etc, etc......High pressure fluids are dangerous. I think for peace of mind and safety, you'd be better to get a new rail as soon as you can. :thumb:

Cheers,

Mark
 

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Discussion Starter #14
It's not a tapered thread.

Looks like Loctite 55 - which is a nylon sealing thread will do the job - being nylon it's diesel proof.

I tried ptfe - it sort of dissolved and didn't last as long as the silicone tape.

God bless Loctite.

I'm too tight to replace the whole fuel rail - and the cost would probably be more than the value of the car. If I can just keep it going until the lease car arrives in September.
 

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Discussion Starter #16
Just checked the pressure sensor this morning - leaking again - no signs of the silicone tape (wrapped around the thread) - it must just get dissolved.

Anyway in desperation I tried the same trick (wrapping around thread) with normal pvc electrical tape - cut into a thin strip and stretched over the thread. Well bugger me its worked, no diesel leak, nowt.

I still nipped into the local Screwfix for the Loctite 55 - just in case - but at the moment fingers are crossed.
 
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