Help! - can I replace 63 litre tank with 55 litre tank??

[Treeman612]

Can i fit a replacement 55 litre tank straight in to car, which has a leaking 63 litre tank?
GSF are currently back order for 63 litre tank. No idea when available.
Euro Car Parts have 55 litre tank available now, but no point buying it if I can't do straight swap for 63 litre tank.
Any good advice welcome - if I don't swap tank over, I'm gonna stub my ciggy out one day before I get in the car and BOOOOM!!!!

[Treeman612]

Please help, guys - someone out there must know if the 55 litre tank will bolt straight in to replace a 63 litre tank? - are all the sender fittings etc etc the same?

[Simon13]

i'm not 100% but i can't seeing the smaller tank not fitting as both came on the E30, i can't see them mounting in a different way either? just one is a bit smaller

[Brianmoooore]

Smaller tank will fit directly in place of the larger one, BUT you may have to replumb the return fuel line.
Some cars have the return line going to a stub pipe on the tank, others use a second connection on the fuel pump.

[Simon]

You will need to change the sender for the relevant tank size, for an accurate reading, the wiring connectors are also the same.

[Treeman612]

Many thanks, guys - makes sense. I have just looked on my ETK disc, and if I'm reading it right, the earlier 55 litre tank has only one hole in it, the 63 litre has two. (Presumably because early injected cars have external fuel pump, later ones in is integral in the tank.)
Surely if I fit a 55l tank, I'm going to be left with 'sending unit assy metal tank', part no. 16 14 1 179 720 with no hole in the tank to mount it??

[Brianmoooore]

If your original tank has two senders, and the new one doesn't have a place for the left hand one, then you will need to short together the wires that went to that sender. You might than have to swap the sender in the fuel pump for a single type as well to get sensible readings on the gauge.