Anyone tried Leak Seal on a petrol tank?

[JonB]

Hi

I have some petrol smells in my car and while removing the rear seats for cleaning, discovered that the horsehair matting under one of the bases smelled suspiciously "petrolly". It's not a strong smell, but I suspect a leak in the tank.

Now, a long long time ago I had a TR7. I was going along a motorway and hit something. There was a "klonk!" and suddenly a lot of exhaust noise. Maybe my exhaust clamp came loose. When I looked under the car, I found fuel dripping out of the tank, which had been hit by something and perforated. Not good when you are lying under the car on the hard shoulder getting soaked in fuel.

I called for assistance and the Fire Brigade turned up and emptied the tank, throwing the fuel in the verge. The car was recovered to a local garage and I repaired the exhaust. However, for the tank it was a bit trickier and the only solution I could come up with was to clean the rust away from the perforations and apply a layer of this stuff:

http://www.loctite.co.uk/loctite-4087.h ... 2657075201

Once it had set I refilled the tank and no leaks occurred, right up to the time I sold the car.

My question is, has anyone tried using this gunk on an Elan tank, and was it a good repair that lasted? I'm sore tempted to try it, if I do find a leak.

[draenog]

Yes, I have. I found a leak just over 3 years ago:

lotus-carbs-f40/fuel-tank-replace-repair-t32729.html

I did a temporary fix at the time using Leak Seal and the tank's still fine. I did pick up a very good condition petrol tank at Castle Combe this year, but I'm in no hurry to remove the tank again...

[nmauduit]

to my limited experience it works best as preventive precaution (when you notice oxidation in the tank but the sheet metal is still solid). When pinholes start to drip, usually the side of the pinhole(s) are very thin and weak, and when you brush or push the pinhole becomes too big to hold the goo. Next step would be to patch with fiberglass or at least epoxy on fabric grabbing on suitably scratched surrounding so that the goo would just have to seal the inside and not achieve any mechanical function.

[alan.barker]

If the Tank has a hole fit a new one. Petrol and grp burn very well
Alan

[steve.thomas]

Jon,
The petrol smell in the area of the rear seat squabs may well be from the tank breather pipes that exit the floor pan. The pipes should have a rubber grommet but it may be missing or perished. There are many threads on here about the issue of petrol smells and some modifications you can make to overcome them. I've found that plugging the pipes with wooden pegs that have a much smaller diameter hole thru them has eliminated the smells but still provides enough breathing for driving, although filling the tank is slow.
Regards
Steve

[alan.barker]

I suggest you do the mod to the filler neck with a MX5 non return. This stops fuel leaks with a full tank and fuel all over the wing when taking bends.
Alan

[JonB]

I suggest you do the mod to the filler neck with a MX5 non return. This stops fuel leaks with a full tank and fuel all over the wing when taking bends.
Alan

Got a link?

[vincereynard]

I think there has been a few. Here's one -

lotus-carbs-f40/fuel-spillage-from-filler-t31759.html

[alan.barker]

That's the one, fantastic mod and no more destroyed paint on the back wing
Alan

[JonB]

I did find another one which didn't use the MX5 part. It was in the Club Lotus magazine and involved threading a smaller diameter breather pipe up through one of the existing fat pipes, then connecting LH/RH pipes together with a tee off to the filler neck, and a second tee to the small diameter pipe. Followed by blanking off the breather hole in the fuel cap. This resolves both issues (sloshing fuel and petrol smells in the garage) and looks easy to do. Doesn't preclude fitting the MX5 valve later, so this is what I'll try first.

Edit: the attachment in this post has the article: lotus-carbs-f40/fuel-tank-fuel-filler-leakage-t32899.html#p222091

[alan.barker]

Even if you solder the little hole in the filler cap it will still leak on corners with more than half a tank of fuel.
Putting the MX5 non return in the rubber filler neck is very easy and cheap.
The mods to the breathers is nothing to do with the MX5 non return.
Alan

[Elseezed]

Back to the topic. Yes I used POR 15 tank sealer after a small hole was patch welded.
To apply, the tank has to be out of the car.
My tank was like new inside apart from that small hole. I used the sealer as insurance.

Patch

Les