Piaggio Porter - Leaking fuel tank options

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Tue 15 Aug 2023 19:15
Piaggio Porter - Leaking fuel tank options - badbusdriver

So following on from an earlier post stating petrol smell but no sign of leakage, it definitely is leaking!. Must only be when above a certain level because I filled up today and had a look under the back when I got home. There is a visible drip every 4-5 seconds, which is not great but does go some way towards explaining why it seems to be thirstier than I'd expected!

I have three options.

First is a new tank, obviously the most expensive but best for peace of mind with long term ownership in mind?. Cheapest seems to be from the Italian Piaggio Porter specialist I have used a few times now, but still just under £400 inc shipping and tax (I've seen ones at nearly twice that!)

Second is to try and repair the one on the vehicle. But that would entail a lot of hassle re draining, removing and prepping the tank (I had been looking at using something like POR15?).

Third option is to try and find a used tank and do as above but while able to continue using the vehicle till ready to swap them over. To that end, there seems to be one used tank on Ebay (204418864549) at £50 plus postage (probably more for me than the £8 stated due to my location.

Any opinions gratefully received on any of this. Whether to bite the bullet and get a new one?, how easy/successful a repair would be?, and whether the one on Ebay looks OK or too far gone?

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Tue 15 Aug 2023 19:47
Piaggio Porter - Leaking fuel tank options - paul 1963

Presumably as you've mentioned por15 it's a metal tank? Personally I would get a new one if funds allow, second choice would be to remove it and repair, soft solder would work OK providing its cleaned well.

As a after thought I seem to remember ( or dream?) That the vintage motorcycle brigade use some sort of liquid sealant that's sloshed around the inside of the tank...

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Tue 15 Aug 2023 19:57
Piaggio Porter - Leaking fuel tank options - Adampr

As previously mentioned, Knightcott Motors is near me. As well as selling Piaggio, they break them. Website suggests they have tanks; new and used.

If you go down that route, I can collect from them and send it on at cost if they get funny about delivery.

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Tue 15 Aug 2023 20:04
Piaggio Porter - Leaking fuel tank options - paul 1963

A very generous offer Adam! I'm the same, I'll always help a fellow ( regular) contributer if I can.

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Tue 15 Aug 2023 20:31
Piaggio Porter - Leaking fuel tank options - badbusdriver

As previously mentioned, Knightcott Motors is near me. As well as selling Piaggio, they break them. Website suggests they have tanks; new and used.

If you go down that route, I can collect from them and send it on at cost if they get funny about delivery.

Keep forgetting about them Adampr, it was the chap there put me off the "shortened" lhd one I was looking at online a few months ago!. But I will have a look at the website.

A very generous offer re sending it though, so thank you very much!.

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Tue 15 Aug 2023 19:59
Piaggio Porter - Leaking fuel tank options - elekie&a/c doctor
Repair or replace involves the same amount work . Once the tank is off the van , I’m sure there are plenty of specialist rebuilders that can advise whether the tank is economically repairable.
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Tue 15 Aug 2023 20:36
Piaggio Porter - Leaking fuel tank options - badbusdriver
Repair or replace involves the same amount work . Once the tank is off the van , I’m sure there are plenty of specialist rebuilders that can advise whether the tank is economically repairable.

I figured that if I am to try and repair it myself, doing it with the tank that is on the vehicle means that it will inevitably be off the road for the duration. Which, if I mess it up (entirely possible) could end up longer than ideal!. If I am working on another tank, I can keep working in the meantime.

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Tue 15 Aug 2023 21:45
Piaggio Porter - Leaking fuel tank options - Metropolis.
Repair or replace involves the same amount work

Not sure I agree with this elekie. If you have a new tank, you are just swapping them out. If you repair, you are also paying (or DIY time) to repair before refit. In both circumstances it’s a case of remove and refit, unless you can manage to repair in situ.
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Tue 15 Aug 2023 20:27
Piaggio Porter - Leaking fuel tank options - badbusdriver

Presumably as you've mentioned por15 it's a metal tank? Personally I would get a new one if funds allow, second choice would be to remove it and repair, soft solder would work OK providing its cleaned well.

As a after thought I seem to remember ( or dream?) That the vintage motorcycle brigade use some sort of liquid sealant that's sloshed around the inside of the tank...

As far as I can tell, that is what POR15 is Paul. You pour it into the empty and clean tank, slosh it around and then remove what is left. Looking at reviews, it does seem to be effective assuming prep and instructions are followed correctly. Though I have read that because it is so runny initially, pinholes may need something like duct tape to temporarily seal them while it cures. And apparently can be several days before it properly hardens. Which is one of the reasons I thought getting another 2nd hand tank might be a good option.

Edited by badbusdriver on 15/08/2023 at 20:33

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Thu 17 Aug 2023 01:42
Piaggio Porter - Leaking fuel tank options - edlithgow

I've used an external glass fibre and resin patch on a Marina fuel tank leak, which held for a few years until the car was scrapped. A few decades ago, though, and its alleged that more recent petrol formulations are more aggressive and will dissolve polyester resin.

If I had such a problem currently, I'd try epoxy externally, assuming I could locate the leak. I have some JB Weld and some other epoxy stuff that I bought for a damaged spark plug hole.

Brazing you have to fill the tank with water and manouvre the hole to be the highest point, otherwise you risk an explosion in the vapour filled void space.

I believe POR15 is an epoxy. Didn't know it was used as an internal tank sealer, but Americans seem to use it for everything. With such sealers, you are supposed to clean up the tank (which will probably be rusty inside) by shaking it with gravel or nuts and bolts.

Electrolysis might be a good option too,for motorcycle tanks, with the tank as the cathode and a sacrificial anode down the filler, but this might not be easy to arrange with a car/truck tank. Maybe the fuel guage sender port would give anode access.

When I had this problem on a 2-stroke motorcycle I initially just stopped using the tank, and ran it on petroil premix from the separate wee oil injection tank. Longer term I planned to use a scooter plastic tank disguised as/in a top box, but was able to source a new steel replacement tank fairly cheaply.

Id think with the relatively good access of a trucklet there might be a possibility of sourcing and mounting a plastic (or steel?) tank, either from something else, or improvised from a jerrycan or similar.

Dunno about MOT inspection though.

Temporary/emergency fix, soap is said to work, though I've never tried it.

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Tue 15 Aug 2023 21:38
Piaggio Porter - Leaking fuel tank options - Metropolis.
Are you sure it is the tank that’s the problem and not a fuel line running from the top?

If it is the tank, I suggest taking the initial pain, if you can manage it, and buying new, the one on eBay looks close to end of life and you might end up buying twice, and fitting twice.

Always a good idea to know the part number if you don’t already, searching by that can yield many more results from OEM suppliers.



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Tue 15 Aug 2023 22:46
Piaggio Porter - Leaking fuel tank options - bathtub tom

The only times I've experienced leaking tanks was:

1. Austin Princess with a corroded seam. Replaced.

2. Austin Allegro that had a rusty hole near the top that the owner wasn't aware of until they filled it for a long journey. Replaced.

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Wed 16 Aug 2023 06:08
Piaggio Porter - Leaking fuel tank options - badbusdriver

Are you sure it is the tank that’s the problem and not a fuel line running from the top?

No actually. Went out later last night to put a container under it, to get an idea just how much was leaking, and it wasn't dripping any more (fuel gauge is still showing full)?

I'm sure it must be "losing" petrol while I'm driving because it is using a lot more fuel than I expected. Owners reports suggest 38-42mpg average, and though I haven't worked it out (no trip meter), I'm sure it is some way south of that!. Caddy was averaging around 43-45mpg and one tankful at around £80 (from the light coming on) would do most of my monthly round. Yesterday I put £40 in for the third time this month and I've still a third of my round to do.....!

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Wed 16 Aug 2023 06:58
Piaggio Porter - Leaking fuel tank options - Metropolis.
www.whatvan.co.uk/buyers-guide/buying-a-used/buyin...d…-piaggio-porter#:~:text=What%20you%20are%20looking%20for,has%20not%20done%20so%20already.


“If you are contemplating buying a second-hand Porter then the first thing to do is to peer underneath from the rear, according to the advice from website UsedVanExpert.co.uk. What you are looking for is corrosion on the fuel pipes towards the centre of the van and where they meet the fuel tank. If present, then sooner or later fuel will start to leak, if it has not done so already. Those pipes will need replacing if they are rusty, says UsedVanExpert, so you should get the van’s price reduced by £200.”


Worth a look
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Wed 16 Aug 2023 07:27
Piaggio Porter - Leaking fuel tank options - Metropolis.
Interesting that it didn’t drip despite being basically full.

Have you tried idling it for a while stationary with the bucket underneath and see if the fuel appears that way?
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Wed 16 Aug 2023 07:37
Piaggio Porter - Leaking fuel tank options - paul 1963

Needs to go on a ramp so you can have a good look around.

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Wed 16 Aug 2023 09:39
Piaggio Porter - Leaking fuel tank options - Andrew-T

<< I'm sure it must be "losing" petrol while I'm driving because it is using a lot more fuel than I expected. >>

Of course that could be due to line leaks, or simply fuel sloshing about while you drive, and reaching a leak near the top of the tank. Agree that the first step is thorough examination from below.

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Wed 16 Aug 2023 16:25
Piaggio Porter - Leaking fuel tank options - badbusdriver

Thanks for all the great advice. I've decided to hold off on the replacement tank (new or used) till I've had a chance to properly investigate what is going on. Once I've got this months round finished, I will take everything off the back and get the tipper body up so I can have a good look at the fuel lines (which own F did recommend on a previous thread). It does seem like a known problem area going by the What Van quote from Metropolis.

Is replacing fuel lines a tricky job or something a (relatively) unskilled DIY-er could do?, or would it be better going to a garage?

New starter should arrive tomorrow, that does appear fairly straightforward to do, though I'll need to work out how to access the battery as the lock on the case doesn't seem to work.....

The joys!

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Wed 16 Aug 2023 17:01
Piaggio Porter - Leaking fuel tank options - elekie&a/c doctor
Replacement of fuel lines shouldn’t be too difficult. Really depends on access to the routing . It’s probably a combination of steel and flexi pipes . Any rubber type pipe needs to be the correct specifications for the rated fuel pressure.
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Wed 16 Aug 2023 17:22
Piaggio Porter - Leaking fuel tank options - badbusdriver

Thanks Doc!

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Thu 17 Aug 2023 01:47
Piaggio Porter - Leaking fuel tank options - edlithgow

Couldn't you use Cunifer (sp?) brake pipe? Easier to bend, and wont ever rust, (though I suppose COULD be some electrolytic corrosion where it meets steel.)

Not big enough bore? Run two?

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Thu 17 Aug 2023 08:38
Piaggio Porter - Leaking fuel tank options - John F

Thanks for all the great advice. I've decided to hold off on the replacement tank (new or used) till I've had a chance to properly investigate what is going on.... so I can have a good look at the fuel lines (which John F did recommend on a previous thread).

Two posts, umpteen replies, and still no precise diagnosis of the incontinence! Can't advise treatment without diagnosis.

Is replacing fuel lines a tricky job....?,

Not if you only have to replace a short corroded stretch that's leaking (see my post in your previous thread. Tools required - small hacksaw, a length of rubber reinforced fuel line, two small jubilee clips. Cost - a few pounds only. Do keep us posted.....

PS Clean and protect the rest of the fuel line while you're at it.

Edited by John F on 17/08/2023 at 08:41

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Tue 22 Aug 2023 01:05
Piaggio Porter - Leaking fuel tank options - edlithgow

PS Clean and protect the rest of the fuel line while you're at it.

I rub with aluminium foil for this, initially dry, to remove surface rust, then with vegetable oil, for protection and cosmetics.

If in a hurry, linseed oil sets faster, "boiled" linseed oil faster still. You should have very good access on a tipper trucklet.

Note that this will fill pits and I'd think it would be quite able to fool an MOT inspector, so you have to be your own inspector, and not treat anything that looks actually dangerous

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