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Siphoning tank on Mk2

Posted: Mon Mar 22, 2021 6:10 pm
by rosie
Has anyone successfully siphoned their tank please?

I’m getting a new custom exhaust made but the mechanic couldn’t do the welding because there’s a small leak from the tank’s filler hose and I’ve got half a tank of fuel left in there. He’s asked me to use up the fuel and take it back to him empty, at which point he’ll replace the faulty hose whilst making the exhaust.

I’ve not used up the fuel as quickly as expected so still have loads in there and thought it might be easiest to siphon it, rather than driving round in circles for two days trying to use it up.

Is it possible to get a a tube into the tank, and out again at the end of the process?

Re: Siphoning tank on Mk2

Posted: Mon Mar 22, 2021 7:17 pm
by C 20 CCO
It should be easy enough to siphon fuel using a decent fuel hose. I would try going in to the tank via the inspection cover under the back seat. This would help you monitor how much fuel is leaving the tank.


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Re: Siphoning tank on Mk2

Posted: Mon Mar 22, 2021 7:58 pm
by mark1gls
There is a flap on the tank to stop you poking in a tube from the filler neck so you will need to go in from underneath the back seat.
I’ve found if you are just above the red you can remove the fuel filler neck no problems but I’ve had my car up on axle stands so it’s at an slight angle.

Re: Siphoning tank on Mk2

Posted: Tue Mar 23, 2021 8:55 am
by Village Idiots
My understanding of the flap at the entrance to the tank is that it hinges forward to allow unrestricted fuel flow whilst filling the tank from a fuel pump but will not hinge backwards and thus stops fuel surging up the filler neck upon the car's 'fierce' acceleration. If that is the case you should be able to work a tube past to siphon fuel. You may, however, suffer the embarassment of the tube jamming as it may pull the flap back towards its closed position and having to drive to your mechanic's with it hanging out of the filler. Incidentally, how do you drive the car to your mechanic's if you've siphoned off all the fuel?
This post was written with a certain amount of tongue in cheek!

Re: Siphoning tank on Mk2

Posted: Tue Mar 23, 2021 10:32 am
by rosie
Thanks guys.
I didn’t realise there was another way into the tank, I was worried that even if I could get a tube into the tank that it would catch on the flap when I tried to pull it back out. I’ll investigate the inspection cover.

Apparently I have to drain it completely, then put in a thimbleful of fuel for a slightly stressful rush-hour drive to the garage through the city centre hoping I don’t run out halfway there. Exciting times!

Re: Siphoning tank on Mk2

Posted: Tue Mar 23, 2021 12:38 pm
by GT_II
C 20 CCO wrote: Mon Mar 22, 2021 7:17 pm It should be easy enough to siphon fuel using a decent fuel hose. I would try going in to the tank via the inspection cover under the back seat. This would help you monitor how much fuel is leaving the tank.
Would it be feasible to suck through the fuel pickup tube at the top of the sender unit to create a syphon without removing the sender - from other postings the sender units seem prone to breakage?

Re: Siphoning tank on Mk2

Posted: Tue Mar 23, 2021 1:32 pm
by C 20 CCO
Good shout.... I have read other posts where the units have broken. All depends whether your using a tool that straddles across the top, instead of only part way. But I would connect a rubber fuel pipe to the pickup and go from there 👍🏻

Re: Siphoning tank on Mk2

Posted: Tue Mar 23, 2021 11:52 pm
by mark1gls
Pull the fuel out of the tank via the fuel pick up underneath the back seat, I guess your car will have the plastic type fuel sender which are easily broken and expensive to replace.
The will be 2 pipes and an electrical connection.
If they lift the car at the back you can have just above the red on the gauge and no fuel will come out when removing the filter neck and rubber joining hose as I’ve done it when changing mine.

You are having an exhaust made, fit it up and weld it off the car away from the fuel if you are worried about it, lots of places and people have exhausts made all the time and most cars will have more than “a thimble of fuel “ in their tanks....