I had another look at that 1098 with the brand new tank. Looked like a lot bigger gap on that. Should have taken some pics.
I bet. We were buying another house with a triple garage, but that went wrong last week. So now some dosh has been freed up .
They are made from Polyamide 6 - if wet and or 'moist' they will grow significantly from bone dry - it's inherent in the polymer structure as it is hygroscopic and swells as it draws moisture in. Use non Ethenol Fuel and it will remain stable. This doesn't mean it has broken down and became unserviceable. But it would be interesting to know what an 'original gap' was a new tank stood for a while would normalise to +2% in weight due to airborne water absorption.
I knew about the Ethenol, but finding a BP or Esso station with around a 100 mile tank range could be challenging. Same with the wet and dry Polyamide, not sure if stories about putting an affected tank in the airing cupboard work either?
If a 'dry' airing cupboard it will cause it to dry out, shrink back and loose weight as the moisture evaporates out - but to dry a single PA6 granule properly you need 80 degrees for 4 hours so you will need a few days in a dry environment at a much lower temperature. Question is: is an airing cupboard dry, or just warm? The additives are supposed to help but never looked into them...
How about drying the tank and sealing it, would that work? Should just add, I'm not sure if there was much if any fuel in that new tank.
Wait for a reasonably priced one and pounce - or get a bigger volume one and befit more. You can always swap it back when you sell so it's only a savings scheme
