This is the second one this year. Any ideas what might be causing premature failure?

 

Crappy design and fabrication. Get a Forge or RMW/Canton one and be done with it. I bought a Forge tank the first year I got my Mini as a preventive maintenance item and I'm pretty happy with it.

 

There is a bad batch floating around out there too. We went through 3 until we got a good one a while back. You will notice the seam gap is somewhat larger on the bad new ones vs the good new ones. I suggest buying from a MINI dealer.
Reasons why MINI dealer and not mail order company...
#1 they sell a lot parts and most likely sold all the bad stock already
#2 Any part purchased at MINI has 2 year warranty that includes parts and labor. So you install it and it breaks. They fix it for free. Just keep all your receipts.

 

There is a parallel thread here where someone who bought the tank at a MINI dealer (MINI of Peabody), but installed it themselves, did not have it fully fixed for free upon failure. When the part failed within the two year period, they took it to a dealer (but not the dealer from whom they purchased the part). The repairing dealer only covered parts because of self-install...

https://www.northamericanmotoring.co...nk-lasted.html

 

You did not get this from me but this is right out of handbook.

 

That is a great piece of information right there. Thank you, or, er, umm, whomever provided that