I needed to drive 500km (return) this weekend, so I topped of the fuel tanks on my V12 and went merrily on my way last saturday. We arrived at our destination, parked the Jag in the underground parking and went to the hotel lobby for check in. After check in we went back to the car to get our stuff.
The parking garage smelled of fuel and a nice puddle of Shell V-Power 100 was building up underneath the car....imagine the horror....
the fuel was dripping down in the center of the rear axle, as far away from the exhaust as possible...

There wasn't much I could do at that moment, so I pretended to not have noticed anything and went back to the hotel. When we came back at the car yesterday, no more gas smell, no puddle of fuel, no dripping....I started the car, she fired up immediately and with no incontinence whatsoever ;-)....

On the way home, the penny finally fell:
I had overfilled the fuel tanks....made the 250km single trip on the left tank, with the right one basking in the sun and not being emptied....

At least I know now that the overflow system works like it should....

 

Unexpected fuel on the ground, never a good feeling

 

The penny hasn't dropped for me. I can't conjure up any reason or scenario where fuel dripping on the ground is a normal or expected thing.

"Overflow system"?

I can't think of what you're referring to....but I'm only two sips into my first cuppa coffee.

If you over filled the tanks the gasoline would've been dripping on the ground at the time you were filling them. Other than that all gasoline should be safely contained in the pipes and tanks....and not dripping on the ground, ever!

I'd be looking for a leak and/or a problem with the venting or change-over system.

Cheers
DD

 

At the rear of the filler neck, a hose is connected that is routed to the underside of the car, right next to the axle. I suspect we don't have carbon canisters or evaporators in Europe (at least not in the 80's)....

I have checked and double checked every fuel line, switch over valve and found everything to be pristine and in full working over. The fuel returns to the tank it should return to, not problems whatsoever...
Can't come up with another explanation than "overflow" tubes...

 

I'm not aware of any build configuration that provides overflow-to-the-ground and such an arrangement isn't shown in the parts or service manuals

But, there are lots of things I'm not aware of and Jaguar literature isn't always accurate!

Personally, I'd pursue it further but if you're happy, I'm happy


Cheers
DD

 

If the tanks were overfilled, there would be fuel above the anti-surge flaps in the filler neck. If the flaps are stuck partly open, or the seal on the filler cap wasn't sealing well, fuel could surge past this and into the filler cap well where the only way out is via the well drain tubes. These drains are there to drain water away.

However, there is another rubber tube that joins at the front of the fuel filler casting and disappears into the front of the rear wing. These are the breather tubes for the petrol tanks. Again, if the anti-surge flaps are not doing their job, fuel could end up going down these tubes too, but where it would end up I don't know.

 

Two theories:


1. A "normal" reaction in an atmosphere vented system. As was the case in the USA a long time ago. pre carbon canister, surge valves and the like. Tank filled to the neck! Long run heats fuel. Location of each just over the rear resonators. Expanded fuel dumps though the vent. No reoccurrence unless the same conditions recreated.


2. The changeover valve stuck. Only once. Fuel returned to the "wrong" tank. It overflowed through the atmospheric vent. may or may not ever happen again.


Carl

 

Hi,

Yes also Dutch models have the vaporator. That's just for the gasoline smell. It won't suck in and "dump" any fuel.

--
Denk dat er toch wel een probleem is met een vacuüm klep. Zie Nederlandse forum.

 

But mine is a German model.... ;-)
Thanks for the input though...
Bedoel je met het Nederlandse Forum dat van de JDCH?

I have successfully recreated the failure yesterday:

Fill both tanks to the brim and let it bake in the sun for a few hours.
The fuel level definitely rises above the filler neck and is drained through the water drain tubes.......

 

This is a good lesson for all of us. Back when I was a teenager (dinosaurs still roamed the earth) American cars did not have canisters, sealing gas caps, etc. If you filled your tank right to the brim and parked it and the weather turned hot, the gas would expand and flow out of the filler neck all over the back fender. If you had a car with the the tank neck under the back licence plate, it was even worse at overflowing (but, at least it didn't get on the fender paint). My Dad taught me to not fill it to the neck. I guess this is one of the few advantages of being old.

Jeff

 

And, still, I'm pretty sure it should have the expansion/vent system shown here:

https://www.jaguarclassicparts.com/u...ipes-and-hoses


In all my Jaguar literature there is no mention of this system being installed only for certain markets. But, ya never know with Jaguar...or me!

Hose #19 connects to the filler neck.

If your car has this system it'll be easy to see the pipes in the boot. Just look in the area under the package shelf, about where the underside of the shelf and the "C" pillar come together

I'm still not convinced that gasoline overflow onto the ground, due to expansion, was Jaguar's design intent. It just doesn't sound right!

Cheers
DD

 

To keep it in English (Sorry). I started a research thread in the Dutch forums to build back a LEFT GASOLINE TANK. There are a lot of vallued replies and photo's / Handbook / Schemes.

1. My Post: https://www.jaguarforum.nl/forum/top...comment-183448
2. Also with my trace down of the Gasoline smell in the interior while driving with the window open: https://www.jaguarforum.nl/forum/top...comment-182533 -> lots of info.
3. and also some replies at my post here on the forum, same thread as 2. but in English. : https://www.jaguarforums.com/forum/x...-200256/page2/

Maybe it helps understanding the full working EU 3 series gasoline system

 

I have overfilled Nix a couple times, forcing the nozzle past the automatic cut-off, and the only way I knew, because I was watching the pump and not the hose, was gas began running out on the ground.

Series 2 at least has an overflow hole just behind the filler on each side.

Overflow passes through a hose *Right* onto the ground by your feet. The capacity of this well makes a puddle 18 inches in diameter, Right under the car, and is a bit embarrassing.
(';')

 

Those are intended as rainwater drains....but any liquid will run thru 'em

According to the ROM, the Series III tanks cannot be overfilled (not sure how they accomplish that) and allow for 10% fuel expansion. Well, I'm sure they can overfilled if you try hard enough but I think they meant 'cannot be overfilled under normal circumstances', assuming typical fuel nozzle click-off.

In any case, providing a drain-off for an accidental over-fill isn't the same thing as intending, by design, for raw fuel to spill on the ground due to expansion on a hot day. I've never had that happen, nor expected it to, on any car I've owned, older or new-ish, even in Las Vegas in August !


Cheers
DD

 

That one's on me:

Having to drive 500Km with a V12, I filled both tanks right to the brim (way beyond auto click-off). I did this, because the prices of fuel in The Netherlands are reaching ridiculous levels at the moment.
We have to pay around € 1.75 for a litre nowadays...
Because I live near the German border, I always fill my vehicles in Germany, where the prices are 40 cents cheaper per litre.
I didn't want to risk having to tank in The Netherlands, so I put as much fuel into the tanks as possible.
Left tank was fine, because I drained that one on the outward trip.
The right tank though was not used and was exposed to full direct sunlight for several hours....

OH: and Series III also have the water drain holes, just like SII........

Starting to wonder now: is 500 km (310 miles) a normal distance to drain both tanks (80 liters) while running about 80 mph constantly?

 

Not a V-12, but just to see how far I could go on a *Full* load of gas, I once traveled over 425 miles on 24 gallons, and had a cushion of less than half a gallon left when I filled.

Obviously YMMV.
(';')