In the early 1970's I lusted after the XJ6. I thought it was the most beautiful thing on wheels, but I worked in a filling station and these were rich guys' cars. The first time I noticed a customer filling up an XJ6, he seemed to take quite a long time to fill the tank and it came to quite a lot of money for the time but then I saw him go around the back of the car and he opened the other filling cap and started filling it again. This really impressed my teenage brain. Within a year, thanks to good fortune I bought my own. As soon as I could, I took it to a filling station and told the attendant to "fill her up - both sides". I loved that car.
One point about the system , on S3s at least, is that the fuel selection for the right tank requires the valve to be powered (ie working, no wiring faults or blown fuses. When the system is passive , fuel is drawn from the left tank. When I do long trips I draw down the right tank first (use it while you have access), then use the left. It can be a long way between gas stations where I live.
I was a bit baffled on my series 3 V12 as the fuel always returns to the right tank- now I know why. I did modify mine so that I have two pumps instead of just the one as my changeover valve had died and a new pump was cheaper!!! Now the relevant pump is selected and then ( of course ) the left pump was filling the right tank from the return. A big thank you for explaining all that. I shall delve into it in the next day or two.
Very interesting I just bought an S3 XJ6 and I am thinking of making a compartment for the pumps and valves to separate them from the trunk so your luggage has less interference with this and less chance it start to smell of fuel if a leak occurs
Hi Adam,..thanks for sharing and explaining how the twin fuel tanks work. About a month ago I bought a 1982 Jaguar XJ6 Series 3 and now I have a good idea on how those twin fuel tanks work. Thanks Adam. A hello from Boston, Massachusetts, U.S.A.
My father converted our 1979 series 2 xj6 to 1 pump system and the valve system was control by the dash switch he kept having issues with the two pump system so in 1981 he looked at his series 3 fuel injected system and made something similar for carb fed engine . Father is a great engineer he so skilled. Because he can draw up systems and make them where i can do the theory but not so good and the practical Other than rover and lancia jaguar xj6 are my fav cars. My dream is to convert one to an ev . But being colour blinds wires are an issue
Two tanks,great! Put diesel in my XJC by mistake in Hamburg.No problem,put petrol in the other tank and drained the diesel next day through the plug at the bottom of tank.
One of the things that has always interested me is crash safety and how it evolved. I usually drive American cars and I like 69-72 the best because they had the small bumpers, but also a modicum of safety equipment. I'm really surprised to see how the fuel tanks are setup on these jaguars! Especially since we had a big thing here on the states about chevy trucks from 73-87 having fuel tanks outside the frame rails that would rupture and catch fire in a side collision. Also 65-70 or so mustangs have a drop in fuel tank with no firewall on the rear seat so a rear end collision could rupture the tank, and slosh fuel into the entire interior of the car if the rear seat came loose in the collision. I'm surprised I never heard anything about how these Jaguars do in a rear end collision. The location is very vulnerable to an offset rear collsions and the pumps and electronics near the rear are ripe for a spark. I assume the relatively low production of these compared to my other two examples is why i have never heard of them. I can't even google a picture of a crashed xj6. Sounds like a fuel cell or foam racing style tank would be much safer. I had assumed the duel tanks were under the rear seat like more modern cars and they needed the dual tanks because the driveshaft was in the way.
twin fuel tanks in Jags started with the MK-X, then the S type then the 420, then the 420-G, then the Series 1, 2, and 3 XJ-6 and XJ-12 from 1968 to 1992.
It seems that the reason why there are twin fuel tanks is that the big spare wheel did not fit in the beautifully sloping boot, otherwise than laying horizontally on the boot bottom. The spare wheel thus took the place of one single tank. Then two smaller tanks were fitted in each wing to give the car sufficient range. I suppose it was a technical complication to have the twin tanks filled via only one filler cap.
It is obvious that it is critical to know how to tell if fuel is returning to the correct tank. I drove xj series 2 o a warm day. When I shut the engine off I smelled fuel at rear of the car. I opened the tank.door and high pressure vapor rushed out, taking over a minute Thor the pressure to normalize with atmospheric pressure. ( also my ac was not working.)
Hey! So I’m having issues with my series 3, every time I start it fuel spews out of the right fuel tank, I heard you can install a Tee tank kit but do you know what could be causing this? And what I should do to fix this? You’re my only hope!
hi buddy i have a xj12L 1975 had all new fuel lines new pumps carbs rebuilt i ran the car but stored it over winter i put gas additive in both tanks now i turn ovwr the new pumps working but no fuel to the carbs car wont start even the tanks each have $50 in each but my emergency cut off valve under dash at passenger side wires are of is this the problem please and thanks super videos by the way keep up the good work
I need to know if there's a third fuel pump on a 95 Jaguar xj12 I got the back too in the tank running but for some reason I'm sure not getting no fuel to the engine
Good video but not quite right re all series 3 xj6 have the fuel filter in the boot. I have an early series 3 and the filter is in the engine bay. Also the changeover switch says "fuel" not a picture of a pump as with later 3's.
The Series 3 I bought yesterday has right tank disconnected, the return switch has been removed, I'm guessing it failed & one tank was overflowing. I will investigate & get both tanks working, however, the car has barely been driven for years, other servicing, maintenance & cosmetics will take priority in coming weeks, it will be some time before both tanks are operating.
Hi Adam. I'm Neil in UK, and thinking of buying a nice condition XJ6 1986 4.2litre Jaguar. So I know it has two fuel tanks, but how can I check to see if the tanks are in good condition before I purchase the car, as I understand they can get quite rusty under those rear wings. The car has been stood for a few years, but runs. But it wont run smoothly, and cuts out when releasing the throttle. Seems to be running on all 6 cylinders ok. Any advice you could give me will be much appreciated. Thanks.....Neil
I really don't see the point of having 2 tanks. Has anybody ever tried to connect both tanks with a hose (bottom to bottom) so it can be used as one big 90L tank?
I am in the process of designing a dual tank fuel system for my Aston Martin DB5 replica project. I am using a 1966 Jaguar XK 4.2 engine from a 420. I am using a 1996 BMW Z3 unibody "chassis" for the suspension, steering, brakes and main structural substructure....wheelbase and trackwidth are fairly close. Since the XK engine is very heavy I think it is important to shift as much mass as possible to the rear to help balance the car for decent handling. Therefore rear "saddle" tanks behind the rear wheel wells very similar to the Jaguars make sense. Non A/C DB5s also used dual tanks for that reason. The Lotus Esprit also had dual tanks, but with a "balance tube" so that fuel could be filled from both sides ...as well as being burned equally. Is it possible to use a balance tube in a Jaguar fuel system, and have one pump and filter? Thank you.
@@LivingWithAClassic I’m fitting a new pump, filter, hoses today and going to try to crank up for the first time! Anything else I should be doing before I try to turn on the engine?
Hi adam Great explanation I own a series 2 6L The precious owner replaced the 2 fuel pumps for one electric pump When i started the car after the wintertime (4 months in the garage), no fuel was coming from one of the tanks. After checking the pump, I could not find anything After switching over manually to the other tank, fuel starting flowing and the car started without any issue Hearing to your explanation, could it be the valve is stuck? I deliberately moved over to using ecofriendly fuel (aspen based) before the wintertime in order to prevent these issues What is your guess the problem could be? PS both tanks were fullwhen parked for the winter
Thanks Adam.Greetings from Cape Town,S,Africa.Just discovered your channel and subscribed.Had a general idea how the twin tanks worked,but you filled in the blanks.Starting to restore fuel system of a '89 Double Six I bought recently which had been standing for years at the previous 2ownwers.Managed to drive it home 30km running on five cylinders.Got the Haynes &factory workshop manuals & even 1 showing how to install a Chevy V8,which is also quite popular here,but looking forward to viewing all your videos on especially on the V12's.Also have a properly runing '84 XJS-Cabrio 5.3HE and need all the tips and help I can get to keep them running.You have any experience on converting a V12 to a manual transmission?
Hi Adam I am attempting to return a 1978 Series 2 XJ6 barn find back to a daily driver. I have an issue with the tanks as the left just feeds the right. Sometimes it runs ok but eventually it runs dry by pumping into the right tank. I have a South African S2 which has intank pumps but with carbs. I do not see any valves in system nor an I see a return line. It appears to be one line from the right hand tank with a “Tee” accommodating the left hand tank fuel line. I know that these South African as well as New Zealand and Australia were basically left over parts models but I basically can only use one tank on this set up. I don’t think the Vehicle has been modified so any suggestions.
I have a series 1, and have a question regarding the upper tank hoses on each side. On the top of the tanks closest to the back of the boot, there is a metal outlet valve coming out of the circular hole in the body with a hose attached on each side. Mine are not connected to anything. When i fill up the tanks, the fuel smell is extremely strong. The question is what are those hoses supposed to be attached to and is that where the fuel smell emanates from?
Hi Adam Like you channel have you got your air intake for the heater (by the wipers) on backwards ? on you series 2 v12 ! As it is the opposite for British Jaguars
You mentioned you replaced the OE pump on your series two with a later Bosch from the HE system. Would you happen to have that Bosh part number? I think I found it as Bosch 69469, is that correct? I'm fixing a 76 Series II that was sitting at my local airport since 94. Only has 15k miles!
Great explanation, thanks! Recently purchased XJ6L. Note, it has a GM 350 conversion. I have never pushed the dash "Fuel" switch. At fuel stops I fill BOTH sides and they always have taken equal amounts to fill up. Was something changed in trunk? Am I missing something in explanation?
Brilliant! Question : On my 1981 XJ12 H.E. there is no swoosh sound when I open the filler caps, indicating there is no underpressure in the tanks. However, on my 1985 XJ-SC 3.6 TWR (with one tank only) there is a definite swoosh/underpressure sound. Can it be clogged ventilation or something else? Incidentally, my 1988 V12 Sovereign also had the swoosh sound. Aside from using air pressure etc to blow out ventilation pipes, is there an easy-fix in the filler cap area ?
Thank you, dear, for your good explanation .. I have Jaguar XJ-12 1979 neighborhood car I just bought .. There is a problem with it, which is that the right-hand tank is overflowing with petrol .. Is there any advice that you would give me to address this problem?
Does anyone have info over the "In Tank" pump versions or where they were available? Im removing the tanks today and the fuel system looks a little different than each of these??
Hello super nice videos. Has is xj6 from 1984. It starts to go bad when it's driven about 30 minutes, like it's running gas. Stutters and sets off. If I leave it for an hour, it can go again. There are new filters on it. Do you have any idea? Well, you can help me Vh Jesper lynge.
The switch is on the dash. But if you mean the tank switch in the rear like I showed on the V12, a series 1 doesn’t have one. It is two pumps just like the XJ6 I showed
Hi, this is very interesting thank you. I was wondering what fuel you use in your 75 series 2? Do you use unleaded and add the special additive? Your advice would be much appreciated as I’m getting conflicting advice regarding my 74 series 2 XJ6. Thanks in advance
Living With A Classic thank you so much, I did not realise that. I have just purchased my vehicle and I’ve so much to learn! I am very used to old British cars of the era but not of a Jaguar as they were way out of my reach at the time.
Love your videos. Im new to these beasts. I have a strong fuel smell its driving me nuts. I have noticed lines from the fuel tanks into a (something) that I assume is venting under the rear window. There also a plate in the rear parcel tray over the top of it. What is it?
The XJ6 only has return lines of its fuel injected. I've owned several and done all the work on them myself and also worked on other people's cars. It's become an obsession
Thanks for another great and informative video, I’m watching it now as I suspect that the DD6 I just bought needs a new pump! Hower, you mention the two types of fuel caps, the flush to the body one and the one that’s raised up. Do you know why they were different? On the S3s I’ve had: 1981 German spec - flush 1989 German spec - flush 1990 German spec - raised 1991 Japanese spec - flush I’m happy that the one I just purchased has a flush one, as the one I had before, it really bothered me to have it raised.
Because the flush fit ones were more inclined to let water in if the drain was plugged I think. I know my old series 2 did let water in but the series 3 seems a lot better.
That flapper will piss you off if you try to pour in gas from a gas can when you can't get to the gas station since the gas will fill up and all over the fender and trunk......I had to pour in a gallon at a time using a large screw driver to push that damn flapper down to hold it and then carefully pour in the gas a gallon at a time.........and when you have an old 1980 you will find that switch to switch the tanks will not have a light that works........THEN you look in the owners manual it says OUT for the right side........well if you have had many different cars in your life you will see people say the right is the passenger side OR the exact opposite by saying it is the opposite when you are under the hood and then the drivers side is the right side......of course they didn't have the stupidass dual tanks either.........now ever try working on the rear disc brakes?.........you won't be happy about that if you do and that is another Jaguar stupidass idea.
