Petrol tank leaking

Hi after the help I got off here with my electrics on my xj40, i got it to turn over but now found out that the petrol tank is leaking as quickly as you can put the petrol, I was wondering if you can put in a tank from a xj8 V8 as I found one from a yard that I used to get parts from

There are two completely different XJ-40 tanks with a change at 629285. After XJ40 there are many different tanks in the x300 series XJ6 depending on VIN and market where originally sold. These changes continue further in the two completely different series cars called XJ8. So you will need to start with which XJ40 tank you need and you can be sure that no XJ8 is the same.

Check part numbers

Jonathan …

Have you actually pulled the tank out to determine that’s what’s leaking and not a fitting ? Even if it is the tank it may be repairable.

Always include the year of your car. Earlier models had an external fuel pump and on later models it’s in the tank.

Because of the complications of the fuel line fittings under the car and the filler neck assembly it’s not the easiest tank to remove.

I purchased a XJ40 for a charity run and found rust around the filler side of the rear window, this had allowed water to run down and under the tank, eventually the tank had given up the struggle and started to leak, that may be the case for you.
As has been stated it’s not the easiest job to remove the tank especially if it’s an intank pump style.
The fuel fittings are up behind the diff and you need small hands to get up there.
If it is intank pump the clips only need to be rotated 90 deg to release the pipes.
You could let us know what year car we are addressing in your bio.

Robin …

I Believe that trick of rotating the fuel line clips 90 deg instead of popping them off also works on the earlier models with the external pumps, it did on my '89.

What happens is that due to the hellishly tight quarters up there trying to just rotate a clip often results in it popping off … and THEN YOU ARE IN TROUBLE !! Because of all the crevices around the differential housing / support the odds are very high (depending on what kind of virtuous life you’ve led) that you won’t find it. And as in most things Jaguar you won’t find replacements for these (two different sizes) puppies at your corner auto parts store.

Top tip … before you start playing with those clips tie a string around them (which also isn’t that easy because of the limited space). OK I told you so :sunglasses:

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Hi sorry for the late reply my car is an American spec 1993

I changed the in tank fuel pump on my last car, a 1994 Sovereign. Out of all the jobs I did on that car, and there were many, I think removing the tank was the worst of them all. Even when I had removed the two clips holding the fuel lines both pipes wouldn’t budge at all. They were siezed in place and I struggled for about two days getting them off. It was so much of a PIA that when I suspected the fuel pump might be failing on my current car I paid a Jaguar independant garage to do the job for £350 all in. In 21 years owning 2 XJ40 models that was the first time I’d farmed any job out to someone else.

i had the same problem 10 days ago, for the second time the car did not start after a 2 days rest. After hammering the tank with a rubber hammer the car started again. I found that in the no start situation the resistance of the pump wa megahoms while it was working was almost a short. So there was a false contact in the pump canister. I bring the car to my mechanic without saying i knew the pump replacement was a nightmare. The next morning i passed to tell him also to clean the AC draining tubes and found that he simply rotated the tank and already removed the pump. So i think he spend not so many times in the operation.

I think ease of removal depends on what climate the car has lived in. In countries or parts of countries with high humidity and loads of road salt/brine in winter things are going to get corroded.

That was the case with mine, the two pipes were siezed solid to the tank outlets, plus it didn’t help having to do the job lying on my back with the car on axle stands, barely any room for leverage, I’m guessing it’s far easier with the car up on a ramp because the garage I used completed the job in about 3 hours ! And being another 19 years older now than I was back then it just made sense to pay them to do it :grinning:

Hey I get it! On the one hand I hate to admit I can no longer do the physical things that I could do 10, 20, 30 years ago, but on the other hand, Clint Eastwood nailed it when he famously said “A man’s got to know his limitations…” I would add “…and accept them.” This I learned from my late father years ago, may he rest in peace.

And he also said " get three coffins ready " then a few minutes later added " make that four " :grinning:
It is hard accepting age is catching up a bit, but I think I’m going to make Clint’s " A man’s got to know his limitations " my mantra from now on. It just takes me too long to recover from all the aches and pains after any serious spanner wielding nowadays. :grinning: :grinning: