[Antz]

As said above, it'll be one of the pumps dying that puts pressure on the other. Happens often in 240s now they are getting old. It'll put pressure on the other and they can eventually die leaving you stranded.

You'll need to find out which one is whining and replace it....but they arent cheap whichever one you do as usually the senders are rusty and once disturbed they will fall to pieces.

Its wise to buy a new sender unit, seal and lock ring if you are going into the tank to check that fuel pump or replace it with a new standard one.

The cheaper and more modern option that I have done loads of times is to remove the external pump completely and pipe between it then buy a Walbro 255 from Conceptua Tuning and fit that in the tank in place of the small in tank pump.....unfortunately you'll still need a new sender unit, seal and lock ring.

This is more than man enough to flow a 240 as they are designed for cars up to 400bhp.