apparently a few gc8 rads have done the same recently,reaching the end of their life i guess, mine got an end tank split about 3 weeks after i got my new engine, one heart attack i didn't need, and i replaced it with an ebay alu one.All good so far, six month, mms did say it look very average/crap and didn't fit too well, but it in and works i will just keep my eye on it.