94 XJ12, any idea why there's so much water in the trunk? It looks like it's been there a while.

 

This seems to be a common problem with these Jags - my own car has suffered this in the past. There are a few places I would look.

1. The fuel filler. The rubber 'boot' part of the fuel filler assembly is prone to tearing and can let water into the car. The whole assembly together bolts to the underside of the trunk compartment has a gasket which can leak. On my car the rubber part was OK, but the gasket was leaking. Heres a photo borrowed from ebay to show the part off the car.

Fuel filler assembly with rubber part in centre and gasket round the edge

2. The grommet around the aerial

3. The trim piece at the bottom of the trunk lip between the tail lights - part 5 in the diagram. This is held on by 3 screws recessed into plastic fixings sunk into the metal. Water can get into the trunk around these fixings. This was happening in my car and sealing these fixings solved my leak. Your car is very late and I have been told that on the last cars the trim piece is held on by double sided tape rather than the screws. My car is a very early battery in trunk car which does have the screws. Another place water can get in is related: part 6 in the diagram, the palstic side finishers fixing to the body beside the tail lights. These are screwed in on earlier cars but affixed with double sided tape on the later type. My car didn't leak here but I noted that although the finishers attached with double sided tape, the screw holes were still there, just no longer used. If you have checked the other known leak areas and still cannot find the leak, it may be that this is true for you very late car with a stick on finisher between the lights. It is worth checking even if your trim panel is not held on with screws.



4. The seals around the tail lights

5. The corners of the rear window. Rust here can let water into the trunk. Your car looks to be from a dry state with excellent bodywork so I doubt this is a problem for you.

6. Around the 'D' pillar trims. Again this is mostly associated with rust. The trim is riveted on to the body. rust develops here and the consequent hole leaks into the trunk. I doubt this is a problem on your car since the body looks to be very rust-free and the pillar trims tend to swell if there is a problem and you would have noticed that when preparing the car for paint.

These are the leak points I can think of - I'm sure someone else will add any I have overlooked!

Edited to add a seventh! - the seal around the trunk lid itself. This seems to be one of the less common leak points though. The fuel filler, aeriel grommet and the trim between the tail lights seem to be the most common leak spots. A potential eighth point is the trunk vent baffle located on the side low down and hidden behind the side piece of the rear bumper. IIRC, this is generally only a problem on earlier front-battery cars.

 

Thank you, I think the culprit is the gas tank filler tube. I can see where someone had tried to spread silicone all over the top of that gasket. We don't have rust here in North Texas. Even it it rains, there's no salt and therefore no rust.

 

Those rubber gaiters/gaskets were NLA when I was trying to find one. I was able to fix a tear in one using Permatex black rubber sealant 80338. The drain tube that runs from the gaiter to the bottom of the boot and out to the ground can also come loose, spilling it all in the boot.

 

Hi from Rodoz, My 93 XJ40 wet trunk was caused by seals around the rear tail light. There was also a hairline crack on the LHS lens so the tailight which had water inside. Only occurred after really heavy rain driving on freeway fast. Re sealed tail lights resolved it.