Diesel Leaks

[jaminb]

My winter maintenance has resulted in diesel leaks.

Leak 1. I replaced the primary filter with a copy Racor filter. This appears to weeping diesel from the threads of the tails / barbs. I had to buy new genuine racor tails that were for 8mm pipe but did remember to put the sealing washers in before I screwed in.

Leak 2. I brimmed the diesel tank whilst out of the water and it appears the pressure has caused a leak around the sender unit. This is held in place with 6 self tapers screwed into the plastic fuel tank and looks like it could pull out with the slightest knock.

Heldite appears to be a forum past recommendation but this is not suitable for ethanol and I think diesel now has an element of ethanol in it?

Any other recommendations please? thanks

 

[Boater Sam]

Bad idea to brim a fuel tank.
Check the vent, if its blocked the expansion will cause leaks or even the tank to burst.

 

[jwilson]

Leaks in thin moulded plastic diesel tanks are a nightmare. Ultimately you will have to get inside the tank and reinforce with an inner plate or plates all fittings that are currently held in with self-tappers.

The first time you have a leak in (for instance) the sender you may get away with unscrewing it, cleaning it and the tank surface up, with petrol, making a new cork-nitrile gasket and sealing it down with Hylomar red and/or blue using one size up thicker self-tappers. Red Hylomar better for flat joints, blue good for getting screw threads sealed.

While the sender hole is open, get a long tube and suck some diesel out from the lowest point of the tank. Bet you get some black muck with it......

 

[jaminb]

thanks JW helpful response. Do you have an opinion on CT1 ? If it is as sticky as some other silicones and diesel resistant maybe a possibility?

BS thanks v. helpful after the event. I was following other advice to try and avoid condensation forming over winter. Surely emptying a jerry can down the inlet pipe cannot create anything like the same pressure as a half full diesel tank slopping around in a heavy swell? Bursting the tank!!

 

[wingcommander]

On a warm day the excess diesel should expand out through vent . And leave a nice diesel streak line down the freshly applied antifouling ..Note to self don't overfill.. If the vent is blocked its gotta expand somewhere.

 

[Laysula]

If you have copper washers on your filter you can re anneal them by heating on the gas ring until red and the plunge them into cold water. or alternatively replace them with dowty washers.

 

[jwilson]

thanks JW helpful response. Do you have an opinion on CT1 ? If it is as sticky as some other silicones and diesel resistant maybe a possibility?

Don't use anything that sets as sealant on polyethylene tanks. Before CT1 existed I used a veery expensive hybrid sealant that was claimed to be diesel-proof: it did not work sealing tank fittings on a plastic tank. You need something that stays sticky like Hylomar or similar.

 

[geem]

thanks JW helpful response. Do you have an opinion on CT1 ? If it is as sticky as some other silicones and diesel resistant maybe a possibility?

BS thanks v. helpful after the event. I was following other advice to try and avoid condensation forming over winter. Surely emptying a jerry can down the inlet pipe cannot create anything like the same pressure as a half full diesel tank slopping around in a heavy swell? Bursting the tank!!

We used CT1 on our tank inspection lid. We used a cork/nitrile gasket and a smear of CT1 either side. Seals well

 

[jwilson]

We used CT1 on our tank inspection lid. We used a cork/nitrile gasket and a smear of CT1 either side. Seals well

Was that on a quite flexible polyethylene diesel tank?

 

[[70521]]

If the vent is blocked its gotta expand somewhere.

Usually up the filler tube. Quite safe as it is capable of holding far more than any expansion in the diesel.

 

[geem]

Was that on a quite flexible polyethylene diesel tank?

No, our tank is built in to the boat. GRP tank with 600mm diameter inspection lid about 10mm thick. Definitely not flexible. The gasket and CT1 are flexible so should work on a flexible tank

 

[jaminb]

Usually up the filler tube. Quite safe as it is capable of holding far more than any expansion in the diesel.

That is what I thought, it should just overflow the filler pipe. I think there is a roll over valve on the overflow so it does burp when filling and I think this may have stressed the sender seal. The retro fitted fuel take off for the heater appears to be sealed with a bed of silicone.

Red Hylomar for the threads on the Racor tails?

 

[wingcommander]

Usually up the filler tube. Quite safe as it is capable of holding far more than any expansion in the diesel.

Unfortunately my vent wasn't blocked, and the week of recant warm weather ( good for antifoul applying) confirmed the fact .lol