Diesel fuel tank leak.

Submitted: Sunday, Sep 09, 2012 at 21:02
ThreadID: 97931 Views:10226 Replies:7 FollowUps:2
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Have a very small leak in my long range diesel tank on the hilux. Leak is about half way down at the back on a corner. Presume this was welded then ground down. Have know idea why its started leaking now as its never hit anything. Anyone have an idea for a fix without removing the tank. Have heard that its safe to weld a diesel tank as long as the diesel level is above where the weld will be. No vapour etc. Any other fixes that my be permanent?.
Cheers Graeme.
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Reply By: happytravelers - Sunday, Sep 09, 2012 at 22:08

Sunday, Sep 09, 2012 at 22:08
Hi Graeme

I had a leak in my diesel tank, I used that two part putty type stuff (can't remember the name off the top of my head) where you work the putty in your hand to mix the two parts together and then it sets like metal and can filed, drilled etc. That was about five years ago and the tank's never leaked since.

Just make sure the area is clean, dry and rough up the surface a bit for good contact.

AnswerID: 494604

Reply By: Member - John (Vic) - Sunday, Sep 09, 2012 at 22:43

Sunday, Sep 09, 2012 at 22:43
What brand of tank and how old?

Sounds like a weld is cracking/splitting, take it out and check the whole tank then get someone to do a proper fix.
Bogging it up with some sort of putty won't stop the weld crack/split continuing and it will let you down when you need it the most.

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AnswerID: 494606

Reply By: Ross M - Sunday, Sep 09, 2012 at 23:07

Sunday, Sep 09, 2012 at 23:07
I have welded split fuel oil tanks, 3000litres
I would get a magnifying glass and examine the tank very closely to see EXACTLY where the fuel is leaking. Probably a pin hole in the weld if at a corner. Corners are usually stronger but can leak because of a pin hole.
If quite small I would scratch a few guide lines on the tank to pinpoint the position.
Jack up the vehicle until the fuel is away from the corner and/or drain some fuel out until away from the corner.

File off the top of the leaking area and then run a brief weld at the leak site.
Spray with a bit of carby cleaner to remove any external fuel. Allow to dry and take carby cleaner can away from site.
That is the OH&S bit.
You won't be heating the internal surface to ignition point and there won't be fuel there anyway. You can light a match above a can of Diesel and the smell doesn't ignite.
Just make sure you let all the internal fuel drain from the site before the weld.
If worried about the fuel being lit by the weld, get someone with a mig welder to squirt some argon gas into the tank to drive out the air. CO2 will do.
No oxygen = no flame. Then weld it.
AnswerID: 494609

Follow Up By: Member - graeme W (WA) - Monday, Sep 10, 2012 at 18:34

Monday, Sep 10, 2012 at 18:34
Thanks everyone for the replies.Was going to go the two part but have someone who is going to do what Ross has suggested. looks more like a pin hole than a crack starting but have no idea why its started leaking now.

Cheers Graeme.
FollowupID: 770288

Reply By: Member - Bucky - Monday, Sep 10, 2012 at 04:29

Monday, Sep 10, 2012 at 04:29

Diesel Tanks explode
Make no mistake about it !

Click here

AnswerID: 494614

Follow Up By: Paul and Mel - Monday, Sep 10, 2012 at 20:44

Monday, Sep 10, 2012 at 20:44
they were BRAZING ie using an Oxy/Acet welder, no wonder it went bang. MIG in small doses will be OK.
FollowupID: 770302

Reply By: Bob Y. - Qld - Monday, Sep 10, 2012 at 08:02

Monday, Sep 10, 2012 at 08:02

We had a Hilux on the station that developed a leak, in what sounds like the same place. Think ours may have been a TJM tank???

The safest way would be to remove the tank, and get someone else to weld it. Failing that, either weld it yourself, or use the 2 pack epoxy putty.

If you weld it, then the diesel level should be below the leak, otherwise fuel will leak out & disrupt the welding process. To reduce risk of any dramas, a flexy pipe from the exhaust pipe, with the engine running, and poked into the fuel filler, will reduce any oxygen in the tank.

With the epoxy, it needs to be clean, as Ross suggested, and apply using some pressure to get the epoxy into the crack. Allow to dry before refilling tank.Rock Ape did a very professional epoxy repair on his fuel tank, and it's still there. From memory, his method was quite meticulous, and he finished the job by painting the repair. If you do a search, you may find his post on the repair.

Good luck,

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AnswerID: 494616

Reply By: Member - MIKE.G - Monday, Sep 10, 2012 at 08:22

Monday, Sep 10, 2012 at 08:22
Hi Graeme. Had a seam leak in a Brown Davis tank on a recent trip. Contacted them and they advised a short term fix was to grind back the area, as there is an aluminium coating on the tank, then use an two part epoxy to cover the leak or epoxy a piece of steel over the area. Took it to a mechanic in Atherton and he used Davcon epoxy to seal the seam and painted the exposed area. No problems. The tank has a 3 year warranty which has expired but I have been asked to take it back to the supplier in Brisbane for comprehensive repairs and if need be, they will freight it back to Brown Davis in Vic to assess the fault. Either way I will be getting it repaired properly. Cheers, Mike
AnswerID: 494617

Reply By: Member - hopbush - Monday, Sep 10, 2012 at 17:38

Monday, Sep 10, 2012 at 17:38
Was on a trip recently in my Hilux and whacked my Long Ranger 140 L tank right on the collar around the bung which is situated on the bottom of the tank at the rear and as such, quite exposed. Sent an email to Long Ranger suggesting that it could be a design fault and may be worth looking at re-locating the drain bung to the vertical surface behind the tank. They sent me an automatically generated reply acknowledging my email and a promise to get back to me in a day or so but I have heard nothing to this day and this was about a month ago. The tank is not under warranty and I was not making any sort of claim but I thought thay may have paid me the courtesy of a formal reply.......but obviously not interested.
The tank is only weeping and a bit damp around the damage and does not actually drip so I think at this stage I will simply leave it. I did try some of the metal epoxy stuff but it didn't seem to make any difference, although it is difficult finding the exact location of the leak.
AnswerID: 494645

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