Smell gasoline from the trunk

guys … in n I understand what happened! since I took steps to solve the infiltration of water in the trunk, I can smell gasoline in the passenger compartment, but only if I open a window. I had removed to repair the fuel cap bowl but then everything was perfectly put back in place. why is there a smell?

This is absolutely standard thing. It was even adverised as standard / invluded during brand new sale. The vapour ftom the boot is squeezed out by air coming/pulsing/leaving the cabin. In other words, vairation of air pressure moves the air here and there…
The more air-tight your boot is, stronger the smell of petrol vapour will be.

What a load of nonsense

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but something must have happened … that it was a pressure problem was obvious … but it didn’t happen before …

If you had water in the trunk then I would be inclined to remove the tank to check that it hasn’t developed pin holes.
I purchased a ‘40 that had a leaking window seal and that had holes in the bottom.

this is impossible the tank has been resin-coated inside and outside and the boot has been reclaimed from infiltrations … precisely for this reason the fuel cap was restored, a silicone gasket was built … before it smells, however, no they felt

You probably already double/triple checked that everything was put back together perfectly, but if not, I’d do that. I’d probably do that again even if I had already checked everything.

Also, my 40 had a very very slight trickle leak around the seal of the fuel sending unit that caused a noticeable gas smell in the trunk. I never noticed the smell in the passenger compartment, but I rarely ever drive with a window open.

Larry, not really.
The legend says that Jaguar allowed to build Jaguar Lynx - just to get rid of the “fuel smell in the boot” problem…

Larry, I’m guessing you don’t have a sense of humorur.

Now seriously,

Fuel smell will travel from dark places to entirely unpredicted (my jag was triggering hydrocarbon detector below the passenger’s seat)

Best thing you can do:
1.Buy hydrocarbon detector. It’s £25 for basic or £100 for much better. With this thing you will be able to diagnose any vapour leak - considering that you’re doing it in the garage with static air.
2. Buy bottle of fluorescent dye for leak detection (fuel, aircon etc) and make sure you have UV torch somewhere. Best to diagnose old hoses starting to sip.

  1. Max, have you changed any hose or connection/compression fitting during tank assembly/disassembly???
    Also, new cap gasket doesn’t mean it’s sound, usually Jaguar has a small problem with tiny sealing lip going internally on their caps, this is your main place to look at, especially with mentioned earlier hydrocarbon detector. Every disturbance of the hose and fitting which is 30+year old equals catastrophy. Same thing with “good and cheap” efi fuel hoses made by garage business.

Jaguar is the most fusty and behind the times with nothing else than fuel systems. Their unchanged ‘retro’ design from 70s was still present in the cars with catalytic converters…

My car doesn’t stink unless I go fishing so no need for any detector other than my nose, but thanks anyway. Already have UV lights, dye, leak detector left over from the rebuild of the A/C some years back.
No idea what a Jaguar Lynx is either BTW
Have you actually examined an XJ40 screw-on fuel cap? Not much chance of seepage with that, maybe old XJS’s are not quite so good?

I don’t think Jaguars have a problem with a fuel smell in the boot, unless of course there is a leak somewhere. If you have had the tank out to ‘resin coat’ it I would carefully check the rubber hose that connects to the filler tube and every other pipe and connection that comes from the tank. If you can’t actually see fuel anywhere in the boot the chances are it is vapour that you are smelling, the tank is known to build up a slight pressure sometimes so when you remove the filler cap to refuel you can feel a ‘whoosh’ of air, this slight pressure can force vapours out of any loose connection or split hose.

I think he might be talking about the 'Lynx Eventer ’ it was an estate version of the XJS built in limited numbers by a company called Lynx. I can’t see any connection to that car and Jaguar having a fuel smell problem though ?

Lynx Eventer build by retired bus drivers - was having cabin connected with the boot, hence no complaints related to fuel smell in the boot… Britain is famous from simple and effective solutions.


This is a nice sentence. Really gets to the point… I don’t think we have bad weather in UK, unless of course it’s raining somewhere.

You are saying Jaguars are known to have this problem of a fuel smell in the boot, I am saying they don’t. Any car with a leaking tank in the boot will obviously smell but Jaguars are not particularly known to have fuel leaks any more than any other car. Where are all the posts from XJS owners complaining about this problem which was only rectified by making their car into an estate model ? To suggest Jaguar allowed Lynx to build the estate version just to cure a non existent problem is ridiculous.

I am crushed by your sense of humor, Casso… No wonder you’re a Jag owner…

It’s not about fuel tanks but permeability of fuel hoses. None of the manufacturers these days is making EFI fuel hoses with consideration of permeability as quality factor. Maybe one or two. People are buying EFI hose that is designed to run externally since beginning of 90s (with some Jaguar exlusions).
Other people are taking out their tanks for refurb, forgetting that the rest of their system has more years than oldest porn stars.
Frankly, there is still marine grade EFI hose that can be your best pick.

Lynx Eventer XJS conversion as shown in the foreground of this photo of a 43rd scale model. The XJS that had the most issues with fuel smells in the trunk were the Hess & Eisenhart convertible conversions done in the USA. IIRC some 1996 were produced in 1988 in Cincinnati Ohio by H & E. The issue was the upper and lower dual tanks in the boot and all the attendant piping for fuel and vapor recovery. 1980 XJS Eventer MKII estate

the work on the tank was done 2 years ago and I never had any odors … only 2 months ago when we fixed the water leaks in the trunk it appeared. we fixed the area of the gas cap but everything seems to be fine … only now I smell.

maybe you knocked off a vent hose there’s one near the tank filler spout inside the trunk

I wouldn’t rule out the possibility that something in the fuel tank system has gone bad coincident with your fixing water leaks, i.e., bad luck. So, checking the things that have been called out seems worthwhile.

Or, is it possible you’ve had a gas/vapor leak for a while but didn’t notice it until you made the trunk water tight (and also air tight to some degree.) The same diagnostics would be required in this case. Just a thought.

Or, I hate to state this one, your gas tank reconditioning treatment has failed, though this one seems a bit too coincudental.

this of the tank is the only one that I exclude … for two years no problem and as it happens the smell coincides with the arrangement of the petrol cap … for some arcane mystery the problem is there … even if everything looks in order.