Fuel cap both sides??

[BFG TERRANO]

Sat waiting to fill up today and 1 run of pumps empty and a queue on the other side. No, the pumps weren't out of order but I guess people didn't want to beat their body work up pulling the hose across. Fair enough.

Got me thinking, like some old jags, why don't new cars have a fuel cap either side to enable fueling from either side? Is it just a cost thing?

[SS2.]

Didn't the Jags have two caps because they had two fuel tanks ?

[john2443]

SS2. said:

Didn't the Jags have two caps because they had two fuel tanks ?

[chrisxr2]

Classic mini the same, two flaps for two tanks, rare though.

[BFG TERRANO]

SS2. said:

Didn't the Jags have two caps because they had two fuel tanks ?

They did. But how convenient, to pull up at any free pump not just the one on the correct side.

[Dog Chops]

I seem to remember the Ford Corsair had the filler in the middle, behind the number plate.

[MagneticMeerkat]

It's to do with evaporative emissions. Fuel caps aren't fully sealed, in that petrol vapour escapes through them. Only a certain amount of vapour is permitted to escape as it is deemed a pollutant. Two caps would mean twice the pollution. So they wouldn't pass legislation.


Also on most cars the fuel tank isn't in the middle, it's over to one side. Thus to have another fuel filler would require a load more pipework going through the boot at a weird angle as tanks are filled using gravity. The filler has to point downwards.

Old Jags had a fuel tank on each side and a dashboard control to switch between the two, so the real answer is both legal and practical.

[kambites]

Surely the caps vent on purpose to avoid a pressure lock. I'd have thought you could easily seal one of the two if you wanted to (or have half the leakage from each).

[catso]

Triumph Spitfire had a single filler in the middle just in front of the boot lid...

[CO2000]

Original lotus Europa had 2 filler caps, 2 tanks but linked together so no switching (IIRC)

Edited by CO2000 on Thursday 6th March 19:26

[Axionknight]

chrisxr2 said:

Classic mini the same, two flaps for two tanks, rare though.

Ours has that, but we did it ourselves when we restored it, nightmare to make it look right compared to the original one too.

[BFG TERRANO]

Couldn't 2 caps that vented 50% less still vent the same amount as one?

[Blib]

Lancia Stratos. Two tanks, two caps.

[carinaman]

Dog Chops said:

I seem to remember the Ford Corsair had the filler in the middle, behind the number plate.

E3 too. Bit vulnerable in the event of a shunt.

[Mermaid]

Longer hose, as in German fuel stations.

[BFG TERRANO]

Mermaid said:

Longer hose, as in German fuel stations.

This! Or a support to enable the hose to swing over the car to get to the other side without beating the st out of your car.

[MagneticMeerkat]

BFG TERRANO said:

Couldn't 2 caps that vented 50% less still vent the same amount as one?

Errm... No

Think about it, both caps are the same size so both will have the same degree of sealing. Vapour will rise up both fillers in equal amounts and be vented out of both sides. Fuel caps can't be fully sealed as air has to be allowed into the fuel tank, otherwise the fuel pump would create a vacuum.

Plus there's still the obvious point of the offset tank. The fuel filler has to point downwards, so would end up set at a crazy angle to serve the other side.

[SmithyAG]

Surely the answer isn't to build every car with two fuel caps, but do as most Tesco petrol stations do and have really tall pumps and long hoses, so you can use both sides without having to reel out loads of fuel pump hose and then drape it across your car, adding muck and scratches in the process?

[Who me ?]

Two tanks - optional extra on Landrovers in the 70's .

[Fleckers]

must be me

but in my jag I am able to stop and fill from the wrong side by holding the hose clear of the boot and body work