Fuel tank rust

In 2018, the original petrol tank in my 1990 Clipper had rusted to the extent that it had to be replaced.  So it was.

What a job!

But I assumed this would put the problem to rest for another 25 years.

Wrong!

New fuel filters now clog up within 20 miles after installation.  And bits of rust are visible within them

I have been told that this is because although the original tanks were galvanised, the replacements available now are not.  That's worrying, because it suggests that if I replace the tank again, the replacement may only last another five years or so.  That's an expensive game.

So, a couple of questions, please.

- My former (now retired) mechanic tells me it is possible, although awkward, to clean out the tank through the gauge sensor hole under the back seat.  First with cloths on sticks, then with a vaccuum cleaner.  Well, fine, but how long would that be effective?

- Is there any form of rust passivator one might apply to the inside of the tank, that is immune to petrol, to slow the rust reappearance?

- Are replacement galvanised tanks available anywhere now?

- My mechanic suggested that water had got in after the replacement through the filler (we had replaced both the throat and the cap at the same time, but who can tell how watertight the cap is, although IIRC it was a proper VW one?).  Is there a history of these caps letting water in?

- My car is duel-fuel (with LPG), so I don't have to use petrol.  Except that if I don't for a while, the carb jets tend to clog with dust, which is tedious to fix.  So I normally switch to petrol just before I park for the night.  I have previously had a Clipper with the carb replaced with a Weber, which I think was less touchy.  Is that Weber still available?  Which model is it, please?  Any idea of the price?  I replaced the carb in my present car with a new Pierburg about 10 years ago, but they have a baddish name so I might be prepared to let it go.  It may be getting near its replacement time anyway.

- Any other suggestions, please?

Thanks for your help.

Geor.
 

Firstly and most importantly do not, under any circumstances put a vacuum cleaner in the fuel tank, even if completely empty the fuel vapour will go bang when it gets to the vacuum cleaner motor. Not good.

If you have a new tank (and it's a late model car) then it probably doesn't have a swirl pot in it, in this case that is a good thing.
What you can do is take the tank off, clean it and seal it with a fuel tank sealer. This will coat everything inside the tank with a protective coating that should make it last a lot longer. You can't use it on original tanks as they have a plastic swirl pot and the sealer would bung it all up.

POR15 Fuel Car / Bike (Motorcycle) Tank Repair Sealer (473ml)

or

https://www.rust.co.uk/product/slosh-petrol-tank-sealer-7

J

Hi, I knew someone that dropped a big dirty magnet into his tank - all the rust particles really stuck fast. Not a perfect solution but a temporary measure maybe...?

You Don't need to drop it in the tank, you can get a good rare earth magnet and let it attach to the outside….If it is large enough then you get a bigger field and the rust or Iron will stick to a wider area……

If you have Totally emptied out your tank and Disconnect the fuel lines in a well ventilated area WITH THE TOP DOWN.
If you use a Shop Vacuum on blow and totally dry out the tank of residual gas and fumes, you should be able to clean it with rags on wooden Dowels, don't use metal.
DO NOT ALLOW THE VACUUM MOTOR IN TO THE CABIN OF THE CAR LEAVE IT OUTSIDE OF THE CAR…

If you can't see the rusticated areas of the tank, you may want to take it out and run it to a Radiator Shop and have them Boil it out for you… Then you can use a product like POR15 to seal it internally or a two part epoxy or urethane coating that is designed for coating the insides of tank trucks carrying Fuel or Corrosives.

I would suspect that you also need to look at the fuel filler tube as they rust over the years, and if you replace the tank and not the filler tube you may be looking at the wrong culprit for your new rusting.

my 2 pence.

I'm sorry, but I think this won't work.

AIUI, Magnetite (Fe3O4), one of the iron oxides, is quite strongly magnetic, and so a magnet in the tank could collect it.  However, it is relatively uncommon, and so probably makes up a tiny amount of what is in my tank.

OTOH, Rust (Fe2O3), another one, is effectively non-magnetic, so a magnet in the tank would have almost no effect on it.  It is the most common form of iron oxide,and so probably makes up most of what is in the tank.

So it seems I need to pursue the sponge-out-and-apply-goop approach. [sigh]

But thanks!

Geor.



 

If you park up the car over the winter it's best to leave it with a full fuel tank as that will help reduce any rust as it's full of petrol.  

mark1gls said

If you park up the car over the winter it's best to leave it with a full fuel tank as that will help reduce any rust as it's full of petrol.  

Don't forget to add a fuel stabilizer to it, and run it up to temp then let it idle and cool occasionally.