Hello all!

I've just purchased a 1992 XJ6 XJ40 Sovereign with the boot (trunk) fuel tank. The previous owner informed me of a gas pump issue, however, having noted a substantial amount of rust on the outside surface, as well as a lot of rust and corrosion build up in the fuel filler space, I am going to make the assumption (for now) that I need to source and replace a new tank. There is a very strong odour of fuel (though the tank is empty) within the boot of the car and I've so far managed to get the belts detached and I'll soon start working on the underneath connections. Being based in rural Australia, I'm unsure how easy it'll be to source an XJ40 tank, so I was wondering whether there were any viable alternatives that would fit, even if not using the same brackets as are currently in place.

In the meantime, I'm also looking into a very temporary "fuel tank" system with a jerry can or something to that extent, so that I can test other components such as the very unreliable battery (though this may also be because it has not run since 2017 at earliest, even if the battery is new). Has anybody attempted this before, and if so have any tips? I'm not from a mechanical background but I have a relatively sound knowledge of systems, and have been researching around for a while, just want to be 100% sure I don't end up destroying anything in the process. I'll try to detail with images when I next get a chance where I believe this would attach, and look for affirmation or otherwise.

Thank you in advance, and I can't say how happy I am that I can finally be posting here, even if it is with issues, with my own Jag!

 

Apologies - I should probably note that this is the 4.0L model!

 

If the tank isn't perforated, you can clean it up and reuse it. Treat the rust and you should be good. The pump might be in the tank (early cars were outside on the rear suspension), so a jerry can is unlikely to work, plus you also have the fuel returning to the tank to deal with. If it has sat that long you might have a gummed up pump.

However, this subforum is the generation earlier, the XJ40 is a completely different car, you want to be here: https://www.jaguarforums.com/forum/xj40-xj81-25/

 

Oh damn, sorry I wasn't sure which to post in, but thank you for letting me know!!

I believe the pump to be in the tank as well, very tricky being in the early cross-over period to find until I can actually have a look. What's the best way of treating the rust for longevity, and is there a level of corrosion/rust within the tank at which point I should probably look into alternatives?

 

You can always remove the sender and have a look inside with an inspection camera to see what's in there. Have a new seal to hand, as used ones never seem to reseal.

I'd use a rust converter on the outside and then paint, on the inside, I'd use nothing. Keep the tank full when not in use and it won't rust.

Jaguar's parts listings are invaluable for seeing what you have and part numbers: https://parts.jaguarlandroverclassic...-jaguar-parts/

 

Thank you - that site is perfect! With regards to the sender, is it considered normal for there to be a small amount of space between the edge of it, and the opening of the fuel tank? It's perhaps a couple of millimitres but I wondered if that was potentially a source of the quite potent fuel smell. I don't have a picture when I thought I did or I'd attach it here, but I'll try do do so to demonstrate what I can see when possible. I'll potentially see about adding fuel and seeing how I go then, would a litre or so be enough to run "testing" or is there a number which is considered viable? If there's an issue with the pump or tank I'd prefer to avoid having to drain the tank if possible, but obviously require enough to start the engine. I know of allowing the pump to receive the fuel by turning the ignition to Step II, but my knowledge is patchy. Thank you very much for being a soundboard for my obliviousness!

 

Yes, the sender isn't a tight fit in the tank. It only takes the smallest hole to create a surprising amount of fuel smell, it could be a loose hose on a vent line on top of the tank too. If the tank is dry, you would probably need about 10 litres to bring it up enough to make sure the pump pickup is covered.

However, if it's old fuel, I would drain that fuel and clean the system. Does the pump run with the key on? If so, you can disconnect a fuel line at the engine and use the pump to pump out the old fuel into a container and then put fresh into the tank.

If you have to remove that tank, the lines have to be disconnected I'm not sure about the XJ40, but on the X300 the lines go into the bottom of the tank and are quick connect fittings. They are right above the differential, so not the easiest place to get to. I made a removal tool with a piece of plastic plumbing pipe about 6" long that just fit over the fuel hose, with a lengthwise split so I could get it over the hose. Then push that up into the tank until it unlocks the fingers in the fitting and releases the hose. The hose has a ridge on the end metal portion that goes into the tank, and the catch is fingers like a Chinese finger trap that grabs the ridge. You need the plastic pipe to go over the ridge and push the fingers back, then you can slide the hose out with the plastic over it. It might take some wiggling, as the hose will be held by an O ring inside that probably doesn't want to let go.

Once the tank is out, then you can disconnect the fuel pump module from the top and remove. Again, have a new seal to hand. In Australia, JagDaim in Melbourne are good suppliers

 

Awesome, thank you so much! I'll hopefully get time this long weekend to try and fill her up and try out, with new fuel, the tank is completely empty currently. I've heard the lines underneath are an absolute burden so I'm ready for that eventuality at some point, especially if the pump is in fact a/the problem.

Thanks for the recommendation of JagDaim, and for all your help, sincerely!