Fuel leak in rear

Hi all,got a fuel leak and dripps behind rear wheel. How many places can leak beside bottom screw?
I want to avoid to take take down/out but is not sure if it comes from bottom screw.
It is a serie 3 xj6.

Br johnny

It can be all connections, that’s fuel sender, drains, feed and return line or the tank itself has rusted through.
My advice is, pump the tank dry (turn key to crank in D and collect at the fuel rail for example) and then have a closer look. Unfortunately it all collects at the bottom of the tank so look with a flashlight while it’s still wet.

Good idea so I dont waste the fuel.
Will do that tomorrow.

Good luck. You could of course use the drain plug but that’s messy and you’ll reek of fuel so I‘d make use of the powerful pump which leaves just a bit in the tank.
Removing the tank is some work so try the fuel sender (behind the rear light) and drain plug first. Those are the ones with large rubber seals.

The tank seam (pinch-weld) is a common area to leak on the cars. I used to send them to a radiator repair shop to get ‘brazed’ back in the 1980s and 1990s.

Sometimes you can remove a tail light and see the leak.


most times the leaks will only get noticed due to fuel smell, as fuel evaporates quickly. As a consequence, if you can see the puddle behind the wheel, your leak is very sizeable. If it occurred quickly, i.e. from one week to the other, my money would be on rubber hoses gone or gaskets broken. And David is right. If the fuel pours out so quickly, you might try to save it. No matter which cause, all of them aren’t really funny as you have very limited access through the rear light and in most cases will end up taking down the bumper and the quarter panel.

Good luck - and for the moment maybe disconnect the battery:-)


75 XJ6L 4.2 auto (UK spec)

Any hose and any connection, the tank unit’s seal (tanks full), Johnny - and rust, anywhere…

The gist is to find the leak, which certainly is no easy task - from ‘anywhere’ gravity takes over, and the fuel will follow odd paths downwards. Do check the tank unit seals, readily accessible by remove rear light cluster - and may offer some views in other nooks and crannies…

Is the dripping constant, or related to fuel pump running beforehand? If the changeover/return valve set-up fails; a tank will overflow - though that is not a ‘drip’…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

And that I believe (it’s been a while but I managed to lose some fuel that way) would come out the filler cap and run down the drain tube and down the paint, and at the very least the tank would be obviously and definitely full.