I have no battery vent system installed and plan an installation. After removing the battery I discovered a tube about 3/8 diameter that pierces the floor through a grommet under the battery. Following the hose it went up about 12 inches and disappeared into the right rear fender well. I am not aware of its function: battery fuel, or other.
Next to this tube and on the floor is another hole with a one inch diameter. Is this the hole for the battery vent tube? I would like to get the battery vent system back to stock, but have never seen an XJS and obviously the battery vent system. I have seen the drawing that has the #3 vent pipe, but it is incomplete. Would appreciate your imput
As an aside: i sprayed the battery area with bicarb of soda and H2o and got no foaming reaction....YES there is a Jaguar god!
1993 XJS Coupe
P.S.For the aviation members perhaps I should have said vent tube rather than relief tube

 

On my car the battery tray vent goes down from the tray to a spigot in the floor more or less underneath the tray. This was a safety precaution against the buildup of inflammable fumes from the older type of non-sealed battery. The 1 inch grommet nearby is either just a floor pan plug, or, if it is below the surge tank, it is that tank's drain plug access point from under the car boot floor, or if not below the surge tank one of the holes for the boot automatic venting system vents which on the HE at least, have little vents popped into a row of about 3 or 4 holes across the forward boot floor.

I think that the tube you describe may have been incorrectly connected from the battery tray vent to the boot gutter drain spigot, which also goes pretty much straight down from the boot gutter RHS hinge corner to a spigot in the wing bottom, outboard of the exhaust tunnel. The LHS has one too which also has a Y connection to the filler recess drain.

Greg

 

Thank you Greg for your reply:
Crossing the Atlantic the Colonials change your language
These are questions, not an English lesson.
Spigot is a faucet or tap?
Boot gutter is the flange that circles the outside of the boot?

In your first paragraph: When looking into the boot I see three or four one inch holes open to the ground across the rear of the boot. One of which is under the battery tray

In your second paragraph: A continuous tube exits into the floor below the tray and extends up about a foot and exits through a hole in the right side of the boot about six inches below my interpretation of the gutter(?) Its upper destination is unknown. The installation looks professional and could be made by Jaguar(?) If this tube is a fuel expansion overflow I do not want to modify it. This begs the question “Where is the exit for the battery vent hose?”

In my further unwanted knowledge of batteries and automobiles there is agreement that all batteries stored in a car’s boot or interior must be vented. That applies to sealed and unsealed batteries. From experience with an E-Type, one spark can have you standing next to a crispy critter.

The car is a 1993 facelift, or rhytidectomy, a surgical procedure to improve visible signs of aging.

 

THESE are the vent holes which on my car have a plastic vent in them. As your car is a facelift, it may or may not have the small surge tank below the battery, I am not sure. If you lokk at Jaguar Classic parts, in this sort of area, you may see the diagram that fits your car, which I probably incorrectly assumed was a V12. 2 and 3 are labelled as battery vents parts:

Battery and Cable - Parts For XJS from (V)179737 to (V)226645 | Jaguar Heritage Parts UK

I do not quite follow, maybe because your car is a facelift. Can you post a pic? If not, are you saying a tube does go from the battery tray to the floor? I got the idea it went from the battery tray somewhere else?

If the tube you are talking about goes from the "flange that circles the outside of the boot" and then goes from below that flange down to the hole in the floor below the battery tray, then yes, that is the RHS boot gutter drain. If your battery tray has a spigot coming out of it, and IF the tube currently there definitely does come from the gutter drain, there is no reason not to plumb in a tube from the battery drain into it. But it would be best to understand how OEM it was done before making those changes.

I highly doubt that a fuel vent would be routed through the trunk (boot !). But best to definitely find the end of that hose!

Greg

 

Looking at the Heritage Parts diagram, I have 1, 6, and 7. Nothing else. Two and three are vent components presumably fit in the side of the battery and out the floor. The cable going through 5 is a mystery to me. In the morning I'll look at the gutter and see if there's a drain hole. Your term "spigot" in the US would mean a tap to allow a liquid to flow or not flow. Is that what you mean? If it is i definitely do not have one in the car
Let me clarify the tube location. It comes out of the boot right side wall about six inches below the boot upper edge and a couple of inches back from the boot front wall and goes from there under the battery tray and out the floor.
Thanks for listening.
afterburner

 

The cable going through 5 is the main positive feed to the front of the car which runs from the battery through 5 and then under the floor to the firewall positive posts that feed the starter, alternator charges into etc etc.

Over in the old country a spigot can mean what you indicate, but it also just means a small tube with nothing else in it that comes out of something else (eg the boot gutter !).

On pre facelifts there is a spigot let into the RH front gutter near the rear window corner and LH side ditto. This is a short steel tube poking straight down though the metal gutter floor into the boot. Onto this is afixed a rubber tube that takes water out of the gutter down to the outer wing bottom in the space OUTBOARD of the exhaust tunnel between that tunnel and the actual outer wing curved rear side wing. The LHS one has a Y fitment and also drains any spilt fuel out of the filler cavity.

Your description sounds a bit like it "Let me clarify the tube location. It comes out of the boot right side wall about six inches below the boot upper edge and a couple of inches back from the boot front wall and goes from there under the battery tray and out the floor." BUT I do not really understand the bit about 'boot right side wall". Is the the bottom of the gutter? if not A photo?

On this photo the gutter spigot I am trying to describe is about 2 inches to the right of the RHS hinge and the black rubber drain tube has a piece of white tape round it, and is fixed vertically to the metal spigot, which, if you look carefully, you can just see. The LHS drain hole is in a different place, so forget that for the time being. Your facelift may be different, but if it is a drain tube you have found, it will be fine to use for the battery vent as well.


Equally, your drain tube may go through the floor, whereas on my car the drains go out the bottom of the wing. Anyway, as the battery vent tubes are not there, if there is a vent tube spigot going downwards from the battery tray, no reason not to connect it via a tube to the boot floor using one of the holes already there. If you definitely find out the existing tube you have found IS a rain vent tube, no reason not to plumb into that. Detaching it from the floor and blowing into it should let you hear where it comes out.

As someone once said. USA and England, two nations divided by a common language!
Greg

 

Thanks Greg. There is no drain coming off the gutter. i have decided to punch a hole into a grommet and run the vent out the one inch hole under the battery. I can't get into trouble that way. I burned up one E-type putting in an electric fuel pump and I am a little shy about cutting into unknown tubes.
Your boot was fasinating. That one line looked liike it had a gas filter; did you bypass the original fuel pump and mount another in the trunk?
Just as an aside I had two four year tours in Europe. one in the London area and the othe in Metz. Still looking for a great cup of french coffee and those marvelous meal!
Cheers, my friend, and thank you for yor help

 

If you're talking about the "filter" device on the right side, that's the stock vacuum line running to the ECU, IIRC. My battery vent on my 86 runs through the hole in the boot under the battery.

 

A great pleasure. That red filter is the fuel filter, an aftermarket racing job from Sytec. I had endless trouble with the big Bosch cannister ones in a range Rover I had, so ditched it on the XJS. It has a renewable very fine screen in it, but thanks to the swirl tank sock filter under the battery on my model, the red filter hardly collects anything - so far at least!

The fuel pump is as standard on my car; it is tucked out of sight in the photo at the end of the RHS pipe coming from the red filter. The LHS exit goes down and out the RHS front bottom corner of the boot to the under car pressure feed pipe to the injectors. The thing in the middle of the tank is the fuel sender. Later cars (yours maybe) have an in-tank pump and no swirl tank, I believe. On my vintage the tank gravity feeds the swirl tank under the battery, and the pump is effectively gravity fed/sucks out of that small tank and pumps under pressure to the filter.

Good luck with the car, I am glad you enjoyed your time over this side.

Greg

 

Here's my vent on my 86...YMMV. I added the brass Tee as the napa had a vent on each side and their diagram showed the cells individualize venting per side (better safe then sorry)

 

Thanks, JTsmks. The only similarity with your car and mine is the battery stand, the battery, and the two battery cables. That is all that is in my car. Either Jaguar cleaned it up or the previous owner did. Watching Velocity TV channel (Dish246) the closer you get to stock the more valuable the car. This car is close, that's why I am working on this vent. The fix i mentioned above is only temporary for obvious reasons.
One of these days I will get to see a real Facelift Jag and know exactly how I stand (maybe).

 

mine is with the battery and a second one for the trunk gutter. I also think there is a line around the ECU to prevent moisture buildup, but could be making that up.