Extra Landrover fuel tank won't fill

[popotla]

Landrover have just fitted to my Defender CSW the two extra fuel tanks I bought from Frontrunner, South Africa. One tank (60 litres) is "under-body", and the other (40 litres) fits under the rear fender.

My understanding is that during filling, (diesel) fuel will flow from the outlet in the fender tank, filling the under-body one. Finally, the fender tank fills, giving a total capacity of 175 litres. Later, by means of an electric pump, fuel is sent from the under-body tank to the fender tank, from where it flows - as needed and of its own accord - to the original tank.

The issue is that during fill-up, fuel is not flowing, apparently, to the under-body tank. Yesterday, on fill-up from almost empty (5 to 10 litres left in ??), I got in 121 litres, a slightly odd amount, given that the original tank is 75-litre capacity and the under fender tank 40 litres, as mentioned above.

I wondered if the problem might be due to an air lock in the piping. But wouldn't the breather tube(s) presumably fitted resolve any problem in that regard?

Please, any suggestions?

[Jojo]

Hi mate,
my first guess would be a clogged breather valve/hose as well. However, as it was recently installed, maybe not. From what I understand from your post the auxiliary tank is filled from the usual filler neck, correct? In that case there must be a T-piece somewhere in the filler neck and hose assembly. If I were you I'd check if the grease monkeys really did connect all the tubes and hoses correctly. Good luck!

Cheers

[popotla]

Thanks, Jojo.

From what I understand from your post the auxiliary tank is filled from the usual filler neck, correct?

Correct.

I'm going to have to leave it to Landrover to check. They did take a while to figure out how to do it, and I'm pretty sure it was the first time they've done the job.

[scrambler]

Maybe just me, but how do you know you only had 5-10L left? Do you have three fuel guages? If you do - what are they reading on the three tanks. If not, how do you know the underbody tank was empty? Based on what you've said, your fuel guage will only tell you what is the main tank, and you seem to be trusting that the electric transfer pump is working - might be worth checking that as well! What is the USABLE size of the tanks - (i.e. do the electric pumps leave a few L on the bottom of each tank?)

[popotla]

Hi Scrambler.

The set-up is new. I have only one gauge but the u-b tank has never been filled.

[foz.in.oz]

Are you sure the tank is 6o litres under the body? The website only mentions 45 litre tanks being available.

[nostromo]

(by the way, our electric pump is working)

[nostromo]

We have a defender 90 xtreme td5 (2003 model).
We've fitted an auxiliary tank: a sill tank sitting below the drivers side. Currently we fill it via a filler cap accessed via the rear wheel arch.
We are looking for a way to fill the original tank plus sill tank at existing filler location.

Thanks,

[Blknight.aus]

suitably modified the filler neck from a twin tanked 100 series cruiser works well, use the piping from the same

[Bundalene]

Here is our set-up. I hope to do the same in the Puma we are building up presently. I bought one of those fillers from a 100 Series Land Cruiser as Dave suggests but couldn't get enough head room to clear the top of the spring tower, but then I didn't cut the unit down to much.

http://www.aulro.com/afvb/projects-tutorials/76208-td5-defender-sill-tanks.html

Erich