Cleaning the petrol tank

Would appreciate any tips regarding cleaning the petrol tank from a 1966 Series 1, 4.2, 2+2. I have removed it from the car and found rust inside, including the petrol sump device. Tried various methods, among others, citric acid, baking powder, but to no avail.

Call your favorite supplier
Get a new tank
They are coated for ethanol
Brand new fits great today
They are around 500 dollars or less
I think Welsh might have a sale with 200 of them on the shelf

Mine had sat for 25 years before I got it, so full of rust and crud. The sump was pretty easy to clean. I believe I may have used some diesel fuel or penetrating liquid to free up some of the junk, but then also used a wire brush device in a drill to clean out the rust.

As for the tank itself, I’m in Joey’s camp on this one. I was originally planning to rehab my existing tank, but decided to just get a new one. Just too much work for a questionable end result. I got mine on sale from Welsh a couple months ago, as Joey mentions. I don’t think that sale is still going, because the current price is $595. I’m gathering from your use of the term “petrol” you may be from the UK, so you would likely look to one of the UK suppliers.

Sorry neither of us has actually answered the question asked, but felt the need to offer the opinion. I try to reuse original parts when possible for the dual purpose of originality and thrift, but on this one I think a new tank is worth it.

Hi Charlie,
We clean quite rusty fuel tanks by the following method:

  1. Strap it to the mouth of a small, portable cement mixer.
  2. Place inside the tank 1 kg of sharp blue metal gravel, along with 1lt of Phosphoric Acid based metal conditioner.
  3. Set the cement mixer in motion for a couple of hours.
  4. Empty Fuel Tank, flush with water and then methylated spirits.
  5. When dry, coat with one of the many fuel tank sealers available.



Me too. I followed Joey’s advice and just replaced it with new.

Evaporust works, but surfaces must be kept wetted…perhaps the cement mixer trick.

If I had decided to go the renewal route instead of replacement, I would have used the gravel method Brent suggests.

I didn’t have a cement mixer so I used the tractor.


Here’s the manual version of the cement mixer I used ball bearings but the gravel sounds better.

Give it a twirl every so often

John North
S2 Coupe


I took mine with me on my morning walk every day for a week…

Woke too many of the neighbors on Sunday though… :smiley:


The creativity in this group is just amazing.


Did the neighbors think you were nuts, before this phase?



That’s funny
Vinegar works well you can get phosphoric acid from a pool company
Gravel or nuts and bolts the trick is to agitate it . I’d be reluctant to slosh it the crap fails and then you end up with it in your fuel system
Ask me how I know
Anyone can buy a new one it takes genius to fix the old one as you can see.
It’s not happening over nite give it time

I feel so much better! I thought I was the only nutty one using gravel!

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I took mine to a radiator shop that also cleaned and coated fuel tanks. They tanked it to remove the rust and the coated the inside with a reddish substance that reminded me of strawberry jam. The cost was ninety dollars and six years later I have zero regrets.


I did an electrolysis treatment on a really crusty xjs tank that did a surprisingly good job.

I can’t recall all the details anymore, but you can look it up on the internet. I’ve also used the gravel method which works well if you have the means to get all the stones out!

By far, post-treatment is the most important step to prevent the rapid return of scale.

I’m still laughing about the fuel tank cleaning methods that’s just hilarious


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$500 seems like a bargain now, doesn’t it?

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Depends do you have to buy a tractor …are you on a walking path ? Jim

I cleaned out my original 1966 tank using a kit from Eastwood’s with good results. Then I found pin hole rust through in the area of the support pad. The drain tube from the filler had broken and allowed water into the area below the tank soaking the pad. I replaced the tank and the drain tube. The moral of the story is check for pin holes (and a broken drain tube) before rehabbing the tank.